Transcript
USB4000 Data Sheet
Description
The Ocean Optics USB4000 Spectrometer is designed from the USB2000 Spectrometer to include an
advanced detector and powerful high-speed electronics to provide both an unusually high spectral
response and high optical resolution in a single package. The result is a compact, flexible system, with
no moving parts, that's easily integrated as an OEM component.
The USB4000 features a 16-bit A/D with autonulling (an enhanced electrical dark signal correction), 4
total triggering options, a dark-level correction during temperature changes, and a 22-pin connector
with 8 user-programmable GPIOs. The modular USB4000 is responsive from 200-1100 nm and can be
configured with various Ocean Optics optical bench accessories, light sources and sampling optics, to
create application-specific systems for thousands of absorbance, reflection and emission applications.
The USB4000 interfaces to a computer via USB 2.0 or RS-232 communications. Data unique to each
spectrometer is programmed into a memory chip on the USB4000; SpectraSuite Spectroscopy Crossplatform Operating Software reads these values for easy setup and hot swapping among computers,
whether they run on Linux, Mac or Windows operating systems. The USB4000 operates from the +5V
power, provided through the USB, or from a separate power supply and an RS-232 interface.
The detector used in the USB4000 spectrometer is a high-sensitivity 3648-element CCD array from
Toshiba, product number TCD1304AP. (For complete details on this detector, visit Toshiba’s web site
at www.toshiba.com. Ocean Optics applies a coating to all TCD1304AP detectors, so the optical
sensitivity could vary from that specified in the Toshiba datasheet).
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USB4000 Data Sheet
The USB4000 operates off of a single +5VDC supply and either a USB or RS-232 interface. It has a
22-pin external interface to easily integrate with Ocean Optics’ other modular components for an
entire system.
Features
TCD1304AP Detector
• High-sensitivity detector
• Readout rate: 1MHz
• Shutter mode
Responsive from 200 to 1100 nm, specific range and resolution depends on your grating and
entrance slit choices
An optical resolution of ~1.5 nm (FWHM)
A wide variety of optics available
• 14 gratings
• 6 slit widths
• 3 detector coatings
• 6 optical filters
Integration times from 10 µs* to 10 seconds
16-bit, 3MHz A/D Converter
Embedded microcontroller allows programmatic control of all operating parameters and
standalone operation
• USB 2.0 480Mbps (high speed) and 12Mbps (full speed)
• RS232 115K baud
• Multiple communication standards for digital accessories (SPI, I2C)
Onboard Pulse Generator
• 2 programmable strobe signals for triggering other devices
• Software control of nearly all pulse parameters
• Onboard GPIO – 8 user-programmable digital I/O
EEPROM storage for
• Wavelength Calibration Coefficients
• Linearity Correction Coefficients
• Absolute Irradiance Calibration (optional)
Low power consumption of only 250 mA @ 5 VDC
4 triggering modes
24-pin connector for interfacing to external products
Programmable for standalone operation
CE Certification
*10µs to 3.79ms integration times require the use of Shutter Mode.
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USB4000 Data Sheet
Specifications
Specifications
Criteria
Absolute Maximum Ratings:
VCC
Voltage on any pin
+ 5.5 VDC
Vcc
Physical Specifications:
Physical Dimensions
Weight
89.1 mm x 63.3 mm x 34.4 mm
190 g
Power:
Power requirement (master)
Supply voltage
Power-up time
230 mA at +5 VDC
4.5 – 5.5 V
~5s depending on code size
Spectrometer:
Design
Focal length (input)
Focal length (output)
Input Fiber Connector
Gratings
Entrance Slit
Detector
Filters
Asymmetric crossed Czerny-Turner
42mm
68mm (75, 83, and 90mm focal lengths are also available)
SMA 905
14 different gratings
5, 10, 25, 50, 100, or 200 μm slits. (Slits are optional. In the
absence of a slit, the fiber acts as the entrance slit.)
Toshiba TCD1304AP linear CCD array
nd
rd
2 and 3 order rejection, long pass (optional)
Spectroscopic:
Integration Time
Dynamic Range
Signal-to-Noise
Dark Noise
Resolution (FWHM)
Stray Light
Spectrometer Channels
10µs – 10 seconds
6
3.4 x 10 (system); 1300:1 for a single acquisition
300:1 (at full signal)
50 counts RMS
~1.5 nm
<0.05% at 600 nm; <0.10% at 435 nm
One
Environmental Conditions:
Temperature
Humidity
-30° to +70° C Storage & -10° to +50° C Operation
0% - 90% noncondensing
Interfaces:
USB
RS-232
USB 2.0, 480 Mbps
2-wire RS-232
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USB4000 Data Sheet
Mechanical Diagram
Figure 1: USB4000 Outer Dimensions
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USB4000 Data Sheet
Electrical Pinout
Listed below is the pin description for the USB4000 Accessory Connector located on the front vertical
wall of the unit. The connector is a Samtec part # IPT1-111-01-S-D-RA connector. The vertical mate
to this is part #IPS1-111-01-S-D-VS and the right angle PCB mount is part #IPS1-111-01-S-D-RA.
Pin
#
Function
Input/Output
Description
1
VCC, VUSB, or
5VIN
Input or
Output
Input power pin for USB4000 – When operating via USB, this
pin can power other peripherals – Ensure that peripherals
comply with USB specifications
2
RS232 Tx
Output
RS232 transmit signal – Communicates with a computer over
DB9 Pin 2
3
RS232 Rx
Input
RS232 receive signal – Communicates with a computer over
DB9 Pin 3
4
Lamp Enable
Output
TTL signal driven Active HIGH when the Lamp Enable
command is sent to the spectrometer
5
Continuous
Strobe
Output
TTL output signal used to pulse a strobe – Divided down from
the master clock signal
6
Ground
Input/Output
Ground
7
External
Trigger In
Input
TTL input trigger signal – See External Triggering Options
document for info
8
Single Strobe
Output
TTL output pulse used as a strobe signal – Has a programmable
delay relative to the beginning of the spectrometer integration
period
9
I C SCL
2
Input/Output
The I C clock signal for communications to other I C
peripherals.
10
I C SDA
2
Input/Output
The I C Data signal for communications to other I C peripherals.
11
MOSI
Output
SPI Master Out Slave In (MOSI) signal for communication to
other SPI peripherals
12
MISO
Input
SPI Master In Slave Out (MISO) signal for communication to
other SPI peripherals
13
GPIO-1(1P)*
Input/Output
General purpose software-programmable, digital input/output
(channel number)
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2
2
2
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USB4000 Data Sheet
Pin
#
Function
Input/Output
Description
14
GPIO-0(2P)*
Input/Output
General purpose software-programmable, digital input/output
(channel number)
15
GPIO-3(1N)*
Input/Output
General purpose software-programmable, digital input/output
(channel number)
16
GPIO-2(2N)*
Input/Output
General purpose software-programmable, digital input/output
(channel number)
17
GPIO-5(3P)*
Input/Output
General purpose software-programmable, digital input/output
(channel number)
18
GPIO-4(4P)*
Input/Output
General purpose software-programmable, digital input/output
(channel number)
19
GPIO-7(3N)*
Input/Output
General purpose software-programmable, digital input/output
(channel number)
20
GPIO-6(4N)*
Input/Output
General purpose software-programmable, digital input/output
(channel number)
A1
SPI_CLK
Output
SPI clock signal for communication to other SPI peripherals
A2
SPICS OUT
Output
The SPI Chip/Device Select signal for communications to other
SPI peripherals
NOTE: GPIO nP and nN are for future LVDS capability
CCD Overview
CCD Detector
The detector used for the USB4000 is a charge transfer device (CCD) that has a fixed well depth
(capacitor) associated with each photodetector (pixel).
Charge transfer, reset and readout initiation begin with the integration time clock going HIGH. At this
point, the remaining charge in the detector wells is transferred to a shift register for serial transfer. This
process is how the array is read.
The reset function recharges the photodetector wells to their full potential and allows for nearly
continuous integration of the light energy during the integration time, while the data is read out
through serial shift registers. At the end of an integration period, the process is repeated.
When a well is fully depleted by leakage through the back-biased photodetector, the detector is
considered saturated and provides the maximum output level. The CCD is a depletion device and thus
the output signal is inversely proportional to the input photons. The electronics in the USB4000 invert
and amplify this electrical signal.
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USB4000 Data Sheet
CCD Detector Reset Operation
At the start of each integration period, the detector transfers the signal from each pixel to the readout
registers and resets the pixels. The total amount of time required to perform this operation is ~12µs.
The user needs to account for this time delay when the pixels are optically inactive, especially in the
external triggering modes.
Signal Averaging
Signal averaging is an important tool in the measurement of spectral structures. It increases the S:N
and the amplitude resolution of a set of samples. The types of signal averaging available in our
software are time-based and spatial-based.
When using the time-base type of signal averaging, the S:N increases by the square root of the number
of samples. Signal averaging by summing is used when spectra are fairly stable over the sample
period. Thus, a S:N of 3000:1 is readily achieved by averaging 100 spectra.
Spatial averaging or pixel boxcar averaging can be used to improve S:N when observed spectral
structures are broad. The traditional boxcar algorithm averages n pixel values on each side of a given
pixel.
Time-based and spatial-based algorithms are not correlated, so therefore the improvement in S:N is the
product of the two processes.
In review, large-well devices are far less sensitive than small-well devices and thus, require a longer
integration time for the same output. Large-well devices achieve a good S:N because they integrate out
photon noise. Small-well devices must use mathematical signal averaging to achieve the same results
as large-well devices, but small-well devices can achieve the results in the same period of time. This
kind of signal averaging was not possible in the past because analog-to-digital converters and
computers were too slow.
Large-well devices consume large amounts of power, resulting in the need to build thermoelectric coolers
to control temperature and reduce electronic noise. Then, even more power is required for the temperature
stabilization hardware. But, small-well devices only need to use signal averaging to achieve the same
results as large-well devices, and have the advantages of remaining cool and less noisy.
Internal Operation
Pixel Definition
A series of pixels in the beginning of the scan have been covered with an opaque material to
compensate for thermal induced drift of the baseline signal. As the USB4000 warms up, the baseline
signal will shift slowly downward a few counts depending on the external environment. The baseline
signal is set between 90 and 140 counts at the time of manufacture. If the baseline signal is manually
adjusted, it should be left high enough to allow for system drift. The following is a description of all of
the pixels via USB:
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USB4000 Data Sheet
Pixel
Description
1–5
Not usable
6–18
Optical black pixels
19–21
Transition pixels
22–3669
Optical active pixels
3670–3681
Not usable
In USB interface mode, Ocean Optics software displays 3648 pixels starting at pixel 1 above.
In RS232 interface mode, the USB4000 transmits out the first 3670 pixels.
Timing Signals
Strobe Signals
Single Strobe
The Single Strobe signal is a programmable TTL pulse that occurs at a user-determined time during
each integration period. This pulse has a user-defined High Transition Delay and Low Transition
Delay. The pulse width of the Single Strobe is the difference between these delays. It is only active if
the Lamp Enable command is active.
Synchronization of external devices to the spectrometer's integration period is accomplished with this
pulse. The Strobe Delay is specified by the Single Strobe High Transition Delay (SSHTD) and the
Pulse Width is specified by the Single Strobe Low Transition Delay (SSLTD) minus the Single Strobe
High Transition Delay ( PW = SSLTD – SSHTD). Both values are programmable in 500ns
increments for the range of 0 to 65,535 (32.7675ms).
The timing of the Single Strobe is based on the Start of Integration (SOI). SOI occurs on the rising
edge of φROG which is used to reset the Sony ILX511 detector. In all trigger modes using an External
Trigger, there is a fixed relationship between the trigger and the SOI. In the Normal mode and
Software Trigger mode, the SOI still marks the beginning of the Single Strobe, but due to the
nondeterministic timing of the software and computer operating system, this timing will change over
time and is not periodic. That is, at a constant integration time, the Single Strobe will not be periodic,
but it will indicate the start of the integration. The timing diagram for the Single Strobe in External
Hardware Trigger mode is shown below:
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USB4000 Data Sheet
External Trigger Input
φROG
Single Strobe
t_SOID+TD
t_SSHTD
t_SSLTD
SOI
t_SOID
t_TD
t_SSHTD
t_SSLTD
Start Of Integration Delay (8.2 - 8.5us)
Trigger Delay
Single Strobe High Transition Delay
Single Strobe Low Transition Delay
Single Strobe (External Hardware Trigger/External Synchronous Trigger Mode)
The Trigger Delay (TD) is another user programmable delay which specifies the time in 500ns
increments that the SOI will be delayed beyond the normal Start of Integration Delay (SOID).
An example calculation of the Single Strobe timing follows:
If the TD = 1ms, SSHTD = 50ms, and SSLTD = 70ms then, the rising edge of the Single Strobe will
occur approximately 51.82ms (1ms + 50ms + 8.2us) after the External Trigger Input goes high and the
Pulse Width will be 20ms (70ms – 50ms).
Continuous Strobe
The Continuous Strobe signal is a programmable frequency pulse-train with a 50% duty cycle. It is
programmed by specifying the desired period whose range is 2µs to 60s. This signal is continuous
once enabled, but is not synchronized to the Start of Integration or External Trigger Input. The
Continuous Strobe is only active if the Lamp Enable command is active.
CCD Timing
The USB4000 uses the Toshiba TCD1304AP CCD detector. When synchronizing the USB4000 to an
external trigger source and/or an external light source, especially if the application has strict timing
requirements, it is helpful to have an understanding of how the timing of the signals to the CCD work.
In addition to power and ground, the TCD1304 requires three signals for operation. These signals are
the Shutter (SH), the Integration Clear Gate (ICG) and the Master Clock (M). In normal operation
(i.e., when not using an external signal to trigger the spectrometer), all of these signals are provided
automatically based on the user-defined integration time set in the software. In external triggering
modes, these signals are also provided automatically, but are derived from the external trigger signal
provided by the user. Below is a timing diagram of these signals during normal operation (no external
trigger):
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USB4000 Data Sheet
Non-Shutter Mode
SH defines the integration time, ICG is used to reset the detector between integration periods, and M is
used to clock out the spectral data from the detector. In the diagram above, the detector is operating in
“non-shutter” mode. Non-shutter mode is used whenever the integration time (tINT) is greater than or
equal to 3800us. 3800us is the time it takes for the spectrometer to read out all of the data from the
CCD. Integration times of less than 3800us can be achieved, though the time between integration
periods must remain at least 3800us in order for the spectrometer to have enough time to read out all
of the data from the CCD. This is achieved by using the “shutter-mode” feature of the TCD1304AP as
shown below:
Shutter Mode
Again, these signals are provided automatically by the USB4000, but when trying to synchronize the
spectrometer to an external device, understanding these signals is helpful.
Operational Modes
The USB4000 supports three free-run modes and two triggering modes of operation. They are
described in the following sections. All Trigger Modes require the use of the TCD1304’s Shutter
Mode to minimize trigger latency. For more information on triggering modes, refer to the External
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USB4000 Data Sheet
Triggering Options document for Firmware Versions 3.0 and above located on our website at
http://www.oceanoptics.com/technical/External-Triggering2.pdf. The following paragraphs
describe these modes. For firmware version below 3.0, see
http://www.oceanoptics.com/technical/External-Triggering.pdf.
Also reference the Engineering Note HR4000 and USB4000 Shutter Mode Performance in Hardware
Trigger Mode which is applicable to any operation using the TCD1304 Shutter Mode.
A detailed description of each triggering mode follows.
Normal Mode
In the Normal (Free-run) mode, the spectrometer will acquire back-to-back spectra based on the
integration period specified. After the Integration Cycle completes, the data is read out of the detector
and written into an internal FIFO where it is available for reading. In parallel to this read/write
operation, another integration is occurring. If the data from the FIFO is completely read before the
parallel integration completes, a back-to-back operation will occur. If the data is not read (FIFO
Empty) in this time period, the FPGA will generate an Idle Cycle which is equivalent to one
integration period and the data from the detector is discarded. After the Idle Cycle has completed, the
FIFO Empty status is checked. If the FIFO is empty and a new spectrum is requested by the software,
a new acquisition will begin. If either condition is false, additional Idle Cycles will be generated until
both conditions are true.
Shutter Mode
Shutter Mode is always invoked when the specified integration period is less than 3800 microseconds.
Back-to-back operations are not permitted in this mode because the parallel use of the shutter
operation would corrupt the detector data as it is being read. Once the data is retrieved and written
into the FIFO, a complete Idle Cycle is executed. As in the Normal Mode, the FIFO Empty and the
spectrum request are evaluated to determine what occurs next. Due to the steps required for each
acquisition, the minimum time per acquisition will be approximately three times the minimum detector
cycle time (3 x 3800 us).
Normal (Shutter) Mode
Normal (Shutter) Mode is a hybrid operation which combines the Normal Mode Integration Cycle
with the Detector Reset Cycle that is used in all Trigger Modes. This combination allows the
spectrometer to exhibit the same behavior in a Free-Run mode as it does in the Trigger Modes. In
actuality, the Normal (Shutter) Mode is the equivalent of the External Hardware Level Trigger Mode
with the trigger input stuck high (logic ‘1’).
External Hardware Level Trigger Mode
In the External Hardware Level Trigger mode, a rising edge detected by the FPGA from the External
Trigger input starts the Integration Cycle specified through the software interface. After the Integration
Cycle completes, the spectrum is retrieved and written to the FIFO in the FPGA. As long as the trigger
level remains active in a logic one state, continuous acquisitions will occur with the following
exception. Each subsequent acquisition must wait until a minimum CCD Reset Cycle completes.
This Reset Cycle insures that the CCD performance uniform on a scan-to-scan basis. The time
duration for this reset cycle is relative to the Integration Cycle time and will change if the integration
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USB4000 Data Sheet
period is changed. So the timing sequence is Trigger, Trigger Delay, Integration Cycle, Read/Write
Cycle, Reset Cycle, Idle Cycle(s), and Integration Cycle (if trigger is still high). The Idle Cycle will
on last 2 µs if the trigger remains high and the FIFO is empty and a spectrum request is active,
otherwise the Idle Cycle will continue until all 3 conditions are satisfied.
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USB4000 Data Sheet
External Hardware Edge Trigger Mode
In the External Hardware Edge Trigger mode, a rising edge detected by the FPGA from the External
Trigger input starts the Integration Cycle specified through the software interface. After the Integration
Cycle completes, the spectrum is retrieved and written to the FIFO in the FPGA followed by a CCD
Reset Cycle. Only one acquisition will be performed for each External Trigger pulse, no matter what
the pulse’s duration is. The Reset Cycle insures that the CCD performance uniform on a scan-to-scan
basis. The time duration for this reset cycle is relative to the Integration Cycle time and will change if
the integration period is changed. So the timing sequence is Trigger, Trigger Delay, Integration Cycle,
Read/Write Cycle, Reset Cycle, and Idle Cycle(s). The Idle Cycle will until the next trigger occurs.
Strobe Signals
Single Strobe
The Single Strobe signal is a programmable TTL pulse that occurs at a user determined time during
each integration period. This pulse has a user defined High Transition Delay and Low Transition
Delay. The pulse width of the Single Strobe is the difference between these delays. It is only active if
the Lamp Enable command is active.
Synchronization of external devices to the spectrometer's integration period is accomplished with this
pulse. The Single Strobe High Transition Delay (SSHTD) is a 16 bit value that defines the time period
from the SOI until the Single Strobe pulse transitions high. The Single Strobe Low Transition Delay
(SSLTD) is a 16 bit value that defines the time period from the SOI until the Single Strobe pulse
transitions low. Thus the Pulse Width of the Single Strobe can be calculated using the following
equation:
PW = SSLTD – SSHTD
Both delay values are programmable in 500ns increments for the range of 0 to 65,535 (32.7675ms).
The timing of the Single Strobe is based on the Start of Integration (SOI). SOI occurs on the rising
edge of φROG which is used to reset the Sony ILX511 detector. In all Trigger Modes using an
External Trigger, there is a fixed relationship between the trigger and the SOI. In the Normal Mode
and Software Trigger Mode, the SOI still marks the beginning of the Single Strobe, but due to the
nondeterministic timing of the software and computer Operating System, this timing will change over
time and is not periodic. This is to say that at a constant integration time, the Single Strobe will not be
periodic, but it will indicate the start of the integration.
The timing diagram for the Single Strobe is shown below:
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USB4000 Data Sheet
Single Strobe Timing Diagram
The Trigger Delay (TD) is another user programmable delay which specifies the time in 500ns
increments that the SOI will be delayed beyond the normal Start of Integration Delay (SOID).
An example calculation of the Single Strobe timing follows. If the TD = 1ms, SSHTD = 50ms, and
SSLTD = 70ms then, the rising edge of the Single Strobe will occur approximately 51.82ms (1ms +
50ms + 8.2us) after the External Trigger Input goes high and the Pulse Width will be 20ms (70ms –
50ms).
Continuous Strobe
The Continuous Strobe signal is a programmable frequency pulse-train with a 50% duty cycle. It is
programmed by specifying the desired period whose range is 2us to 60s. This signal is continuous
once enabled, but is not synchronized to the Start of Integration or External Trigger Input. The
Continuous Strobe is only active if the Lamp Enable command is active.
Digital Inputs & Outputs
General Purpose Inputs/Outputs (GPIO)
The USB4000 has 8 2.5V user-programmable digital Input/Output pins, which can be accessed at the
22-pin accessory connector. Through software, the state of these I/O pins can be defined and used for
multi-purpose applications such as communications buses, sending digital values to an LCD/LED
display, or even implementing complex feedback systems.
GPIO Recommended Operating Levels:
VIH(min) = 1.7V
VIL(max) = 0.7V
IOL = 24mA
IOH = -24mA
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USB4000 Data Sheet
GPIO Absolute Maximum Ratings are as follows:
VIN(min) = -0.5V
VIN(max) = 3.0V
Communication and Interface
USB 2.0
480-Mbit Universal Serial Bus allows for ultra fast data transfer. This is the main communication
standard for PC users. The USB BUS also provides power as well as communications over a single
cord, thereby allowing the USB4000 to operate anywhere you can take a laptop computer without any
bulky external power supplies.
RS-232
Also known as serial port communication, RS232 is a standard in PC and industrial device
communications. Using transmit and receive signals this option allows the USB4000 to be a
standalone device, which can output data to other logic devices/controllers such as a PLC or
microcontroller. The USB4000 requires an external 5-Volt power source when operating in RS-232
mode.
USB4000 USB Port Interface Communications
and Control Information
Overview
The USB4000 is a microcontroller-based Miniature Fiber Optic Spectrometer that can communicate
via the Universal Serial Bus or RS-232. This section contains the necessary command information for
controlling the USB200 via the USB interface. This information is only pertinent to users who do not
want to use Ocean Optics’ 32-bit driver to interface to the USB4000. Only experienced USB
programmers should attempt to interface to the USB4000 via these methods.
Hardware Description
The USB4000 uses a Cypress CY7C68013 microcontroller that has a high speed 8051 combined with
an USB2.0 ASIC. Program code and data coefficients are stored in external E2PROM that are loaded
at boot-up via the I2C bus. The microcontroller has 8K of internal SRAM and 64K of external SRAM.
Maximum throughput for spectral data is achieved when data flows directly from the external FIFO’s
directly across the USB bus. In this mode the 8051 does not have access to the data and thus no
manipulation of the data is possible.
USB Information
Ocean Optics Vendor ID number is 2457 and the product ID is 0x1022.
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USB4000 Data Sheet
Instruction Set
Command Syntax
The list of the commands is shown in the following table followed by a detailed description of each
command. The length of the data depends on the command. All commands are sent to the USB4000
through End Point 1 Out (EP1). All spectra data is acquired through End Point 2 and 6 In and all other
queries are retrieved through End Point 1 In (EP1). The endpoints enabled and their order is:
Pipe #
Description
Type
Hi Speed Size
(Bytes)
Full Speed Size
(Bytes)
Endpoint
Address
0
End Point 1 Out
Bulk
64
64
0x01
1
End Point 2 In
Bulk
512
64
0x82
2
End Point 6 In
Bulk
512
64
0x86
3
End Point 1 In
Bulk
64
64
0x81
USB Command Summary
16
EP2 Command
Byte Value
Description
Version
0x01
Initialize USB4000
0.90.0
0x02
Set Integration Time
0.90.0
0x03
Set Strobe Enable Status
0.90.0
0x05
Query Information
0.90.0
0x06
Write Information
0.90.0
0x09
Request Spectra
0.90.0
0x0A
Set Trigger Mode
0.90.0
0x0B
Query number of Plug-in Accessories Present
0.90.0
0x0C
Query Plug-in Identifiers
0.90.0
0x0D
Detect Plug-ins
0.90.0
0x60
General I C Read
0x61
2
0.90.0
General I C Write
2
0.90.0
0x62
General SPI I/O
0.90.0
0x68
PSOC Read
0.90.0
0x69
PSOC Write
0.90.0
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USB4000 Data Sheet
EP2 Command
Byte Value
Description
Version
0x6A
Write Register Information
0.90.0
0x6B
Read Register Information
0.90.0
0x6C
Read PCB Temperature
0.90.0
0x6D
Read Irradiance Calibration Factors
0.90.0
0x6E
Write Irradiance Calibration Factors
0.90.0
0xFE
Query Information
0.90.0
USB Command Descriptions
A detailed description of all USB4000 commands follows. While all commands are sent to EP1 over
the USB port, the byte sequence is command dependent. The general format is the first byte is the
command value and the additional bytes are command specific values.
Byte 0
Byte 1
Byte 2
…
Byte n-1
Command
Byte
Command
Specific
Command
Specific
…
Command
Specific
Initialize USB4000
Description: Initializes certain parameters on the USB4000 and sets internal variables based on the
USB communication speed the device is operating at. This command should be called at the start of
every session however if the user does not call it, it will be executed on the first Request Scan
command. The default vales are set as follows:
Parameter
Default Value
Trigger Mode
0 – Normal Trigger
Byte Format
Byte 0
0x01
Set Integration Time
Description: Sets the USB4000 integration time in microseconds. The value is a 32-bit value whose
acceptable range is 10 – 65,535,000 µs. If the value is outside this range the value is unchanged. For
integration times less than 3800 µs, the integration counter has a resolution of 1µs. For integration
times greater than this, the integration counter has a resolution of 10 µs.
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USB4000 Data Sheet
Byte Format
Byte 0
Byte 1
Byte 2
Byte 3
Byte 4
0x02
LSW-LSB
LSW-MSB
MSW-LSB
MSW-LSB
MSW & LSW: Most/Least Significant Word
MSB & LSB: Most/Least Significant Byte
Set Strobe Enable Status
Description: Sets the USB4000 Lamp Enable line (J2 pin 4) as follows. The Single Strobe and
Continuous Strobe signals are enabled/disabled by this Lamp Enable Signal.
Data Byte = 0 Lamp Enable Low/Off
Data Byte = 1 Lamp Enable HIGH/On
Byte Format
Byte 0
Byte 1
Byte 2
0x03
Data byte LSB
Data Byte MSB
Query Information
Description: Queries any of the 31 stored spectrometer configuration variables. The Query command
is sent to End Point 1 Out and the data is retrieved through End Point 1 In. The 31 configuration
variables are indexed as follows:
18
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USB4000 Data Sheet
Data Byte - Description
0 – Serial Number
th
1 – 0 order Wavelength Calibration Coefficient
st
2 – 1 order Wavelength Calibration Coefficient
nd
3 – 2 order Wavelength Calibration Coefficient
rd
4 – 3 order Wavelength Calibration Coefficient
5 – Stray light constant
th
6 – 0 order non-linearity correction coefficient
st
7 – 1 order non-linearity correction coefficient
nd
8 – 2 order non-linearity correction coefficient
rd
9 – 3 order non-linearity correction coefficient
th
10 – 4 order non-linearity correction coefficient
th
11 – 5 order non-linearity correction coefficient
th
12 – 6 order non-linearity correction coefficient
th
13 – 7 order non-linearity correction coefficient
14 – Polynomial order of non-linearity calibration
15 – Optical bench configuration: gg fff sss
gg – Grating #, fff – filter wavelength, sss – slit size
16 – USB4000 configuration: AWL V
A – Array coating Mfg, W – Array wavelength (VIS, UV, OFLV), L – L2 lens
installed, V – CPLD Version
17 – Autonulling information
18 – Power-up baud rate value
19-30 – User-configured
Byte Format
Byte 0
Byte 1
0x05
Data byte
Return Format (EP1)
The data is returned in ASCII format and read in by the host through End Point 1.
Byte 0
Byte 1
Byte 2
Byte 3
…
0x05
Configuration
Index
ASCII byte 0
ASCII byte 1
…
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USB4000 Data Sheet
Write Information
Description: Writes any of the 31 stored spectrometer configuration variables to EEPROM. The 31
configuration variables are indexed as described in the Query Information. The information to be
written is transferred as ASCII information.
Byte Format
Byte 0
Byte 1
Byte 2
Byte 3
…
Byte 17
0x06
Configuration
Index
ASCII byte 0
ASCII byte 1
…
ASCII byte 15
Request Spectra
Description: Initiates a spectra acquisition. The USB4000 will acquire a complete spectra (3840 pixel
values). The data is returned in bulk transfer mode through EP2 and EP6 depending on the USB
Communication Speed. The table below provides the pixel orderint overview for the 2 different
speeds. The pixel values are decoded as described below.
Byte Format
Byte 0
0x09
Return Format
The format for the returned spectral data is dependant upon the USB communication speed. The
format for both High Speed (480 Mbps) and Full Speed (12Mbps) is shown below. All pixel values are
16 bit values which are organized in LSB | MSB order. There is an additional packet containing one
value that is used as a flag to insure proper synchronization between the PC and USB4000.
USB High Speed (480Mbps) Packet Format
In this mode, the first 2K worth of data is read from EP6In and the rest is read from EP2In. The packet
format is described below.
Packet #
End Point
# Bytes
Pixels
0
EP6In
512
0-255
1
EP6In
512
256-511
2
EP6In
512
512-767
3
EP6In
512
768-1023
4
EP2In
512
1024-1279
5
EP2In
512
1280-1535
…
EP2In
512
14
EP2In
512
3584–3840
15
EP2In
1
Sync Packet
The format for the first packet is as follows (all other packets except the synch packet has a similar
format except the pixel numbers are incremented by 256 pixels for each packet).
20
211-00000-000-05-201210
USB4000 Data Sheet
Packet 0
Byte 0
Byte 1
Byte 2
Byte 3
Pixel 0 LSB
Pixel 0 MSB
Pixel 1 LSB
Pixel 2 MSB
Byte 510
Byte 511
Pixel 255 LSB
Pixel 255 MSB
…
Packet 15 – Synchronization Packet (1 byte)
Byte 0
0x69
USB Full Speed (12Mbps) Packet Format
In this mode all data is read from EP2In. The pixel and packet format is shown below.
Packet #
End Point
# Bytes
Pixels
0
EP2In
64
0-31
1
EP2In
64
32-63
2
EP2In
64
64-95
…
EP2In
64
119
EP2In
64
3808–3839
120
EP2In
1
Sync Packet
Packet 0
Byte 0
Byte 1
Byte 2
Byte 3
Pixel 0 LSB
Pixel 0 MSB
Pixel 1 LSB
Pixel 2 MSB
Byte 62
Byte 63
Pixel 31 LSB
Pixel 31 MSB
…
Packet 120 – Synchronization Packet (1 byte)
Byte 0
0x69
Set Trigger Mode
Description: Sets the USB4000 Trigger mode to one of four states. If an unacceptable value is passed,
then the trigger state is unchanged.
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21
USB4000 Data Sheet
Data Value = 0 Normal (Free running) Mode
Data Value = 1 Software Trigger Mode
Data Value = 2 External Synchronization Trigger Mode
Data Value = 3 External Hardware Trigger Mode
Byte Format
Byte 0
Byte 1
Byte 2
0x0A
Data Value LSB
Data Value MSB
Query Number of Plug-in Accessories
Description: Query’s the number of Plug-in accessories preset. This is determined at power up and
whenever the Plug-in Detect command is issued
Byte Format
Byte 0
0x0B
Return Format
The data is returned in Binary format and read in by the host through End Point 7.
Byte 0
Value (BYTE)
Query Plug-in Identifiers
Description: Queries the Plug-in accessories identifiers. This command returns 7 bytes with the last
byte always being zero at this point. Each of the first 6 bytes correspond to Ocean Optics compatible
devices which responded appropriately for I2C addresses 2 through 7 respectively. The I2C address are
reserved for various categories of devices and the value for each category is shown below.
I2Caddresses 0-1 are reserved for loading program code from EEPROMS.
Byte Format
Byte 0
0x0C
Return Format
The data is returned in Binary format and read in by the host through End Point 7.
Byte 0
Byte 1
2
Value @ I C
address 2
22
2
Value @ I C
address 3
…
Byte 5
Byte 6
…
Value @ I C
address 7
2
0x00
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USB4000 Data Sheet
Detect Plug-ins
Description: Reads all of the plug-in accessories that are plugged into the I2C bus. No data values are
returned.
Byte Format
Byte 0
0x0D
General I2C Read
Description: Performs a general purpose read on the I2C pins for interfacing to attached peripherals.
The time to complete the command is determined by the amount of data transferred and the response
time of the peripheral. The I2C bus runs at 400KHz. The maximum number of bytes that can be read is
61.
Command Byte Format
Byte 0
Byte 1
Byte 2
0x60
I C Address
2
Bytes to Read
Return Byte Format
Byte 0
2
I C Results
Byte 1
2
I C Address
Byte 2
Byte 3
…
Byte N+3
Bytes to Read
Data Byte 0
…
Data byte N
I2C Result Value
Description
0
I C bus Idle
1
I C bus Sending Data
2
I C bus Receiving Data
3
I C bus Receiving first byte of string
5
I C bus in waiting for STOP condition
6
I C experienced Bit Error
7
I C experience a Not Acknowledge (NAK) Condition
8
I C experienced successful transfer
9
I C bus timed out
2
2
2
2
2
2
2
2
2
General I2C Write
Description: Performs a general purpose write on the I2C pins for interfacing to attached peripherals.
The time to complete the command is determined by the amount of data transferred and the response
time of the peripheral. The I2C bus runs at 400KHz. The results codes are described above.
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23
USB4000 Data Sheet
Command Byte Format
Byte 0
Byte 1
2
I C Address
0x61
Byte 2
Byte 3
…
Byte N+3
Bytes to Write
Data
Byte 0
…
Data byte N
Return Byte Format
Byte 0
2
I C Results
General SPI Input/Output
Description: Performs a general-purpose write and read on the SPI bus for interfacing to attached
peripherals. The time to complete the command is determined by the amount of data transferred and
the response time of the peripheral. The SPI bus runs at ~25KHz Clock. The maximum number of
bytes that can be written or read is 61. During this transfer the SPI Chip Select signal is driven to an
active LOW TTL level. Data is transmitted out the MOSI (Master Out Slave In) line on the rising edge
of the clock signal. Data is also latched in the from the MISO line on the falling edge of the clock
signal.
Command Byte Format
Byte 0
Byte 1
Byte 2
Byte 3
…
Byte N+2
0x62
# of Bytes (N)
Write Byte 0
Write Byte 1
…
Write Byte N
Return Byte Format
Byte 0
Byte 1
Byte 2
Byte 3
…
Byte N+1
# of Bytes (N)
Read Byte 0
Read Byte 1
Read Byte 2
…
Read Byte N
Write Register Information
Description: Most all of the controllable parameters for the USB4000 are accessible through this
command (e.g., GPIO, strobe parameters, etc). A complete list of these parameters with the associate
register information is shown in the table below. Commands are written to End Point 1 Out typically
with 4 bytes (some commands may require more data bytes). All data values are 16 bit values
transferred in MSB | LSB order. This command requires 100µs to complete; the calling program needs
to delay for this length of time before issuing another command. In some instances, other commands
will also write to these registers (i.e., integration time), in these cases the user has the options of
setting the parameters through 2 different methods.
Byte Format
24
Byte 0
Byte 1
Byte 2
Byte 3
0x6A
Register Value
Data Byte LSB
Data Byte MSB
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USB4000 Data Sheet
Register
Address
Description
Default
Value
Min
Valu
e
Max Value
24
1
0xFFFF
Time Base
0x00
Master Clock
Counter Divisor
0x04
FPGA Firmware
Version (Read Only)
0x08
Continuous Strobe
Timer Interval
Divisor
48000
0
0xFFFF
Continuous Strobe
Base Clock
(see Register 0x0C)
0x0C
Continuous Strobe
Base Clock Divisor
4800
0
0xFFFF
48MHz
0x0C
Continuous Strobe
LSB Register
4800
0
0xFFFF
48MHz
0x10
Integration Period
Base Clock Divisor
480
0
0xFFFF
48MHz
0x10*
Integration Period
LSB Register
480
0
0xFFFF
1KHz
0x14
Set base_clk or
base_clkx2
0: base_clk
1: base_clkx2
*
*
0x18
Integration Clock
Timer Divisor
0x18*
Integration Period
MSB Register
0x20
Reserved
0x28
Hardware Trigger
Delay – Number of
Master Clock cycles
to delay when in
External Hardware
Trigger mode before
the start of the
integration period
0x28
Hardware Trigger
Delay – Delay the
start of integration
from the rising edge
of the trigger in
500ns increments
*
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48MHz
Version
1.00.0
1.00.0
1.00.0
1.00.0
3.00.0
1.00.0
3.00.0
1.00.0
0
600
0
0
1
N/A
0xFFFF
Integration Period
Base Clock
(see Register 0x10)
1.00.0
3.00.0
1.00.0
0
0
0xFFFF
2MHz
3.00.0
0
0
0xFFFF
25
USB4000 Data Sheet
Register
Address
0x2C
0x2C
&*
&*
Description
Trigger Mode
0 = Free Running
1 = Software
2 = External
Synchronization
3 = External
Hardware Trigger
Trigger Mode
0 = Free Running
1 = Software
2 = External
Hardware Level
Trigger
3 = Normal (Shutter)
4 = External
Hardware Edge
Trigger
Default
Value
Min
Valu
e
Max Value
Time Base
Version
1.00.0
0
0
2
N/A
3.00.0
0
0
2
N/A
0x30
Reserved
0x38
Single Strobe High
Clock Transition
Delay Count
1
0
0xFFFF
2MHz
0x3C
Single Strobe Low
Clock Transition
Delay Count
5
0
0xFFFF
2MHz
0x40
Lamp Enable
0
0
1
N/A
0x48
GPIO Mux Register
0: pin is GPIO pin
1: pin is alternate
function
0x50
GPIO Output Enable
1: pin is output
0: pin is input
0x54
GPIO Data Register
For Ouput: Write
value of signal
For Input: Read
current GPIO state
0x58
Reserved
1.00.0
0x5C
Reserved
1.00.0
26
1.00.0
1.00.0
1.00.0
1.00.0
1.00.0
0
0
0x03FF
N/A
1.00.0
0
0
0x03FF
N/A
1.00.0
0
0
0x03FF
N/A
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USB4000 Data Sheet
Register
Address
0x74
0x78
Description
Default
Value
Min
Valu
e
Offset Value
0
0
Offset Control
Bit 0 = Enable AutoNulling
Max Value
0xFFFF
Time Base
N/A
Version
1.00.0
1.00.0
0
0
0xFFFF
N/A
Bit 1 = Enable AutoNulling Saturation
0x7C
FPGA Programmed
(Read Only)
0x5501
N/A
N/A
N/A
0x80
Maximum Saturation
Level
0x55F0
0
0xFFFF
N/A
0xD4
ADC Convert Delay
0x002E
0
0xFFFF
N/A
0XD8
1.00.0
1.00.0
3.00.0
ADC Convert Width
0x0010 0
0xFFFF
N/A
3.00.0
Notes: * - User should not change these values because spectrometer performance can be affected.
This information is included just for completeness
& - These values are controlled by other command interfaces to the USB4000 (i.e , Set
integration time command).
Read Register Information
Description: Read the values from any of the registers above. This command is sent to End Point 1
Out and the data is retrieved through End Point 1 In.
Byte Format
Byte 0
Byte 1
0x6B
Register
Value
Return Format (EP1In)
Byte 0
Byte 1
Byte 2
Register Value
Value MSB
Value LSB
Read PCB Temperature
Description: Read the Printed Circuit Board Temperature. The USB4000 contains a DS1721
temperature sensor chip which is mounted to the under side of the PCB. This command is sent to End
Point 1 Out and the data is retrieved through End Point 1 In. The value returned is a signed 16-bit A/D
conversion value, which is equated to temperature by:
Temperature (oC) = .003906 * ADC Value
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27
USB4000 Data Sheet
Byte Format
Byte 0
0x6C
Return Format (EP1In)
Byte 0
Byte 1
Byte 2
Read Result
ADC Value LSB
ADC Value MSB
If the operation was successful, the Read Result byte value will be 0x08. All other values indicate the
operation was unsuccessful.
Read Irradiance Factors
Description: Reads 60 bytes of data, which is utilized for Irradiance Calibration information from the
desired EEPROM memory address.
Byte Format
Byte 0
Byte 1
Byte 2
0x6D
EEPROM Address LSB
EEPROM Address MSB
Return Byte Format
Byte 0
Byte 1
…
Byte 59
Byte 0
Byte 1
…
Byte 59
Write Irradiance Factors
Description: Write 60 bytes of data, which is used for Irradiance Calibration information to the desired
EEPROM memory address.
Byte Format
Byte 0
Byte 1
Byte 2
Byte 3
…
Byte 62
EEPROM
Address LSB
EEPROM
Address
MSB
Byte 0
…
Byte 59
0x6E
Query Status
Description: Returns a packet of information, which contains the current operating information. The
structure of the status packet is given below
Byte Format
Byte 0
0xFE
28
211-00000-000-05-201210
USB4000 Data Sheet
Return Format
The data is returned in Binary format and read in by the host through End Point 1 In. The structure for
the return information is as follows
Byte
Description
Comments
0-1
Number of Pixels WORD
LSB | MSB order
Integration Time - WORD
Integration time in µs – LSW | MSW.
Within each word order is LSB | MSB
Lamp Enable
0 – Signal LOW
1 – Signal HIGH
2-5
6
7
Trigger Mode Value
8
Spectral Acquisition
Status
9
10
11
Packets In Spectra
Returns the number of Packets in a
Request Spectra Command.
Power Down Flag
0 – Circuit is powered down
1 – Circuit is powered up
Packet Count
Number of packets that have been
loaded into End Point Memory
12
Reserved
13
Reserved
14
USB Communications
Speed
15
Reserved
211-00000-000-05-201210
0 – Full Speed (12Mbs)
0x80 – High Speed (480 Mbps)
29
USB4000 Data Sheet
Appendix A: USB4000 Serial Port Interface
Communications and Control Information
Overview
The USB4000 is a microcontroller-based Miniature Fiber Optic, which can communicate via the
Universal Serial Bus or RS-232. This document contains the necessary command information for
controlling the USB4000 via the RS-232 interface.
Hardware Description
The USB4000 utilizes a Cypress FX2 microcontroller, which has a high speed 8051, combined with
an USB ASIC. Program code and data coefficients are stored in external E2PROM, which are loaded
at boot-up via the I2C bus.
Spectral Memory Storage
The USB4000 can store a single spectrum in the spectral data section. While spectra is being
accumulated, it is being co-added to the existing spectra in memory. With this approach it is capable to
accumulate any number of spectra (previous limit was 4).
Instruction Set
Command Syntax
The list of the command is shown in the following table along with the microcode version number
they were introduced with. All commands consist of an ASCII character passed over the serial port,
followed by some data. The length of the data depends on the command. The format for the data is
either ASCII or binary (default). The ASCII mode is set with the “a” command and the binary mode
with the “b” command. To insure accurate communications, all commands respond with an ACK
(ASCII 6) for an acceptable command or a NAK (ASCII 21) for an unacceptable command (i.e. data
value specified out of range).
In the ASCII data value mode, the USB4000 “echoes” the command back out the RS-232 port. In
binary mode all data, except where noted, passes as 16-bit unsigned integers (WORDs) with the MSB
followed by the LSB. By issuing the “v command” (Version number query), the data mode can be
determined by viewing the response (ASCII or binary).
In a typical data acquisition session, the user sends commands to implement the desired spectral
acquisition parameters (integration time, etc.). Then the user sends commands to acquire spectra (S
command) with the previously set parameters. If necessary, the baud rate can be changed at the
beginning of this sequence to speed up the data transmission process.
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USB4000 Data Sheet
Upgrading from USB2000
The following is a summary of the changes that may be required if you are upgrading from a
USB2000 to USB4000
•
•
•
Baud rates
• The startup baud rate is programmable through the EEPROM Calibration Entry
#18
• The unit operates at 115.2K Baud, but does not run at 57.6K Baud
Operating Parameters
• The I (upper case) command will set the integration time in milliseconds
• To take advantage of the microsecond integration time capability, use the i (lower
case) command
• Most new operating parameters are set through the FPGA (W command)
Spectral Data
• If only one spectra is “Accumulated”, then data is returned in 16 bit format
• If additional spectra is “Accumulated”, then data is returned in 32 bit format
• The limitation of “Accumulating” 15 spectra is eliminated
Command Summary
Letter
Description
Version
A
Adds scans
1.00.0
B
Set Pixel Boxcar
1.00.0
Set Data Compression
1.00.0
I
Sets integration time (ms increments)
1.00.0
J
Sets Lamp Enable Signal
1.00.0
K
Changes baud rate
1.00.0
L
Clear Memory
C
D
E
F
G
H
M
N
O
P
Partial Pixel Mode
1.00.0
Q
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USB4000 Data Sheet
Letter
Description
Version
S
Starts spectral acquisition with previously set parameters
1.00.0
T
Sets trigger mode
1.00.0
Set FPGA Register Information
1.00.0
Z
Read out Scan from memory
1.00.0
A
Set ASCII mode for data values
1.00.0
b
Set binary mode for data values
1.00.0
i
Set integration value (32-bit value and us increments)
1.00.0
k
Sets Checksum mode
1.00.0
v
Provides microcode version #
1.00.0
x
Sets calibration coefficients
1.00.0
?
Queries parameter values
1.00.0
+
Reads the plugged-in accessories
1.00.0
R
U
V
W
X
Y
Command Descriptions
A detailed description of all USB4000 commands follows. The {} indicates a data value which is
interpreted as either ASCII or binary (default). The default value indicates the value of the parameter
upon power up.
Add Scans
Description: Sets the number of discrete spectra to be summed together. Since the USB4000 has the
ability to return 32 bit values, overflow of the raw 16-bit ADC value is not a concern.
Command Syntax:
A{DATA WORD}
Response:
ACK or NAK
Range:
1-5000
Default value:
1
Pixel Boxcar Width
Description: Sets the number of pixels to be averaged together. A value of n specifies the averaging of
n pixels to the right and n pixels to the left. This routine uses 32-bit integers so that intermediate
overflow will not occur; however, the result is truncated to a 16-bit integer prior to transmission of the
data. This math is performed just prior to each pixel value being transmitted out. Values greater than
~3 will exceed the idle time between values and slow down the overall transfer process.
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USB4000 Data Sheet
Command Syntax:
B{DATA WORD}
Response:
ACK or NAK
Range:
0-15
Default value:
0
Set Data Compression
Description: Specifies whether the data transmitted from the USB4000 should be compressed to speed
data transfer rates. For more information on USB4000 Data Compression, see Technical Note 1.
Command Syntax:
G{DATA WORD}
Response:
ACK or NAK
Range:
0 – Compression off
!0 – Compression on
Default value:
0
Integration Time (16 Bit)
Description: Sets the USB4000’s integration time, in milliseconds, to the value specified. This
command accepts just a 16-bit value and is expressed in ms for backward compatibility with the
USB2000. Use the “i” command for full 32-bit functionality.
Command Syntax:
I{16 bit DATA WORD}
Response:
ACK or NAK
Range:
1 – 65,000,000
Default value:
6ms
Integration Time (32 Bit)
Description: Sets the USB4000’s integration time, in microseconds, to the value specified.
Command Syntax:
i{32-bit DATA DWORD}
Response:
ACK or NAK
Range:
10 – 65,000,000
Default value:
6,000
Lamp Enable
Description: Sets the USB4000’s Lamp Enable line to the value specified
Command Syntax:
J{DATA WORD}
Value:
0 = Light source/strobe off—Lamp Enable low
1 = Light source/strobe on—Lamp Enable high
Response:
ACK or NAK
Default value:
0
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33
USB4000 Data Sheet
Baud Rate
Description: Sets the USB4000’s baud rate.
Command Syntax:
K{DATA WORD}
Value:
0=2400 1=4800 2=9600 3=19200
5=Not Supported
6=115,200
Response:
See below
Default value:
2
4=38400
7=230,400
When changing baud rates, the following sequence must be followed:
1. Controlling program sends K with desired baud rate, communicating at the old baud rate.
2. A/D responds with ACK at old baud rate, otherwise it responds with NAK and the process is
aborted.
3. Controlling program waits longer than 50 milliseconds.
4. Controlling program sends K with desired baud rate, communicating at the new baud rate.
5. A/D responds with ACK at new baud rate, otherwise it responds with NAK and old baud rate
is used.
Notes
If a deviation occurs at any step, the previous baud rate is used.
The power-up Baud rate can be set by setting the EEPROM Memory slot to the
desired value (i.e., 6 for a value of 115,200 Baud)
Pixel Mode
Description: Specifies which pixels are transmitted. While all pixels are acquired on every scan, this
parameter determines which pixels will be transmitted out the serial port.
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211-00000-000-05-201210
USB4000 Data Sheet
Command Syntax:
P{DATA WORD}
Description
0 = all 3870 pixels
th
1 = every n pixel with no averaging
2 = N/A
3 = pixel x through y every n pixels
4 = up to 10 randomly selected pixels
between 0 and 2047 (denoted p1, p2,
… p10)
Value:
Response:
ACK or NAK
Default value:
0
Example
P 0 (spaces for clarity
only)
P 1
N
P 2 N/A
P3
x
y
n
P 4
n
p1
p2
p3 …
p10
Note
Since most applications only require a subset of the spectrum, this mode can greatly
reduce the amount of time required to transmit a spectrum while still providing all of
the desired data. This mode is helpful when interfacing to PLCs or other processing
equipment.
Spectral Acquisition
Description: Acquires spectra with the current set of operating parameters. When executed, this
command determines the amount of memory required. If sufficient memory does not exist, an ETX
(ASCII 3) is immediately returned and no spectra are acquired. An STX (ASCII 2) is sent once the
data is acquired and stored. If the Data Storage Mode value is 0, then the data is transmitted
immediately. If the Scans to Accululate is 1, then the data is returned as WORDs. However, if it is
greater than 1, then the data is returned as DWORDs to avoid overflow.
Command Syntax:
S
Response:
If successful, STX followed by data
If unsuccessful, ETX
The format of returned spectra includes a header to indicate scan number, channel number, pixel
mode, etc. The format is as follows:
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USB4000 Data Sheet
WORD 0xFFFF – start of spectrum
WORD Data size flag (0=Data is WORDs, 1=Data is DWORDs)
WORD Number of Scans Accumulated
WORD Integration time in milliseconds
WORD FPGA Established Baseline value (MSW)
WORD FPGA Established Baseline value (MSW)
WORD pixel mode
WORDs if pixel mode not 0, indicates parameters passed to the Pixel Mode command (P)
(D)WORDs spectral data depending on Data size flag
WORD 0xFFFD – end of spectrum
Trigger Mode
Description: Sets the USB4000’s external trigger mode to the value specified.
Command Syntax:
T{DATA WORD}
Value:
0 = Normal – Continuously scanning
1 = Software trigger
2 = External Hardware Level Trigger
3 = Normal (Shutter)
4 = External Hardware Edge Trigger
Response:
ACK or NAK
Default value:
0
ASCII Data Mode
Description: Sets the mode in which data values are interpreted to be ASCII. Only unsigned integer
values (0 – 65535) are allowed in this mode and the data values are terminated with a carriage return
(ASCII 13) or linefeed (ASCII 10). In this mode the USB4000 “echoes” the command and data values
back out the RS-232 port.
Command Syntax:
aA
Response:
ACK or NAK
Default value
N/A
Note
The command requires that the string “aA” be sent without any CR or LF. This is an
attempt to insure that this mode is not entered inadvertently.
A legible response to the Version number query (v command) indicates the USB4000
is in the ASCII data mode.
36
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USB4000 Data Sheet
Binary Data Mode
Description: Sets the mode in which data values are interpreted to be binary. Only 16 bit unsigned
integer values (0 – 65535) are allowed in this mode with the MSB followed by the LSB.
Command Syntax:
bB
Response:
ACK or NAK
Default value
Default at power up – not changed by Q command
Note
The command requires that the string “bB” be sent without any CR or LF. This is an
attempt to insure that this mode is not entered inadvertently.
Checksum Mode
Description: Specifies whether the USB4000 will generate and transmit a 16-bit checksum of the
spectral data. This checksum can be used to test the validity of the spectral dat, and its use is
recommended when reliable data scans are required. See Technical Note 2 for more information on
checksum calculation.
Command Syntax:
k{DATA WORD}
Value:
0 = Do not transmit checksum value
!0 = transmit checksum value at end of scan
Response:
ACK or NAK
Default value:
0
Version Number Query
Description: Returns the version number of the code running on the microcontroller. A returned value
of 1000 is interpreted as 1.00.0
Command Syntax:
v
Response:
ACK followed by {DATA WORD}
Default value
N/A
Set FPGA Register Value
Description: Sets the appropriate register within the FPGA. The list of register setting is in the USB
command set information. This command requires two data values, one to specify the register and the
next to specify the value.
Command Syntax:
W{DATA WORD 1}{DATA WORD 2}
Value:
Data Word 1 – FPGA Register address
Data Word 2 – FPGA Register Value
Response:
ACK or NAK
Default value:
N/A
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USB4000 Data Sheet
ASCII Data Mode
Description: Sets the mode in which data values are interpreted to be ASCII. Only unsigned integer
values (0 – 65535) are allowed in this mode and the data values are terminated with a carriage return
(ASCII 13) or linefeed (ASCII 10). In this mode the USB4000 “echoes” the command and data values
back out the RS-232 port.
Command Syntax:
aA
Response:
ACK or NAK
Default value
N/A
Note
This command requires that the string “aA” be sent without any CR or LF. This is an
attempt to ensure that this mode is not entered inadvertently. A legible response to the
version number query (v command) indicates the USB4000 is in the ASCII data
mode.
Binary Data Mode
Description: Sets the mode in which data values are interpreted to be binary. Only 16 bit unsigned
integer values (0 – 65535) are allowed in this mode with the MSB followed by the LSB.
Command Syntax:
bB
Response:
ACK or NAK
Default value
Default at power up – not changed by Q command
Note
The command requires that the string “bB” be sent without any CR or LF. This is an
attempt to insure that this mode is not entered inadvertently.
Checksum Mode
Description: Specifies whether the USB4000 will generate and transmit a 16-bit checksum of the
spectral data. This checksum can be used to test the validity of the spectral data, and its use is
recommended when reliable data scans are required. See Technical Note 2 for more information on
checksum calculation.
38
Command Syntax:
k{DATA WORD}
Value:
0 = Do not transmit checksum value
!0 = transmit checksum value at end of scan
Response:
ACK or NAK
Default value:
0
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USB4000 Data Sheet
Version Number Query
Description: Returns the version number of the code running on the microcontroller. A returned value
of 1000 is interpreted as 1.00.0
Command Syntax:
v
Response:
ACK followed by {DATA WORD}
Default value
N/A
Calibration Constants
Description: Writes one of the 32 possible calibration constant to EEPROM. The calibration constant
is specified by the first DATA WORD which follows the x. The calibration constant is stored as an
ASCII string with a max length of 15 characters. The string is not check to see if it makes sense.
Command Syntax:
x{DATA WORD}{ASCII STRING}
Value:
DATA WORD Index description
0 – Serial Number
th
1 – 0 order Wavelength Calibration Coefficient
st
2 – 1 order Wavelength Calibration Coefficient
nd
3 – 2 order Wavelength Calibration Coefficient
rd
4 – 3 order Wavelength Calibration Coefficient
5 – Stray light constant
th
6 – 0 order non-linearity correction coefficient
st
7 – 1 order non-linearity correction coefficient
nd
8 – 2 order non-linearity correction coefficient
rd
9 – 3 order non-linearity correction coefficient
th
10 – 4 order non-linearity correction coefficient
th
11 – 5 order non-linearity correction coefficient
th
12 – 6 order non-linearity correction coefficient
th
13 – 7 order non-linearity correction coefficient
14 – Polynomial order of non-linearity calibration
15 – Optical bench configuration: gg fff sss
gg – Grating #, fff – filter wavelength, sss – slit size
16 – USB4000 configuration: AWL V
A – Array coating Mfg, W – Array wavelength (VIS, UV, OFLV), L – L2
lens installed, V – CPLD Version
17 – Auto-nulling configuration information
18 – Startup Baud rate entry
19-30 – Reserved
Response:
ACK or NAK
Default value:
N/A
To query the constants, use the ?x{DATA WORD} format to specify the desired constant.
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USB4000 Data Sheet
Query Variable
Description: Returns the current value of the parameter specified. The syntax of this command
requires two ASCII characters. The second ASCII character corresponds to the command character
which sets the parameter of interest (acceptable values are B, A, I, K, T, J, y). A special case of this
command is ?x (lower case) and ?W, which requires an additional data word be passed to indicate
which calibration constant is to be queried.
Command Syntax:
?{ASCII character}
Response:
ACK followed by {DATA WORD}
Default value:
N/A
Examples
Below are examples on how to use some of the commands. Commands are in BOLD and descriptions
are in parentheses. For clarity, the commands are shown in the ASCII mode (a command) instead of
the default binary mode. In ASCII mode, the USB4000 transmits the prompt “> “, which is shown.
The desired operating conditions are: acquire spectra with a 200ms integration time, set number of
scan to add to 5, transmit back every 4th pixel and operate at 115,200 Baud.
aA
(Set ASCII Data Mode)
K6
(Start baud rate change to 115,200)
Wait for ACK, change to 115200, wait for 20ms
K6
(Verify command, communicate at 115200)
A2
(Add 5 spectra)
I200
(Set integration time to 200ms)
P1
(Set to acquire every 4th pixel)
4
S
(Acquire spectra)
…
Repeat as necessary
Application Tips
•
•
•
40
During the software development phase of a project, the operating parameters of the USB4000
may become out-of-synch with the controlling program. It is good practice to cycle power on
the USB4000 when errors occur.
If you question the state of the USB4000, you can transmit a space (or another non-command)
using a terminal emulator. If you receive a NAK, the USB4000 is awaiting a command;
otherwise, it is still completing the previous command.
For Windows users, use HyperTerminal as a terminal emulator after selecting the following:
1.
Select File | Properties.
2.
Under Connect using, select Direct to Com x.
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USB4000 Data Sheet
3.
Click Configure and match the following Port Settings:
Bits per second (Baud rate): Set to desired rate
Data bits: 8
Parity: None
Stop bits: 1
Flow control: None
4.
Click OK in Port Settings and in Properties dialog boxes.
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USB4000 Data Sheet
Technical Note 1: USB4000 Data Compression
Transmission of spectral data over the serial port is a relatively slow process. Even at 115,200 baud,
the transmission of a complete 3840 point spectrum takes around 600 msec. The USB4000
implements a data compression routine that minimizes the amount of data that needs to be transferred
over the RS-232 connection. Using the “G” command (Compressed Mode) and passing it a parameter
of 1 enables the data compression. Every scan transmitted by the USB4000 will then be compressed.
The compression algorithm is as follows:
1. The first pixel (a 16-bit unsigned integer) is always transmitted uncompressed.
2. The next byte is compared to 0x80.
•
•
If the byte is equal to 0x80, the next two bytes are taken as the pixel value (16-bit
unsigned integer).
If the byte is not equal to 0x80, the value of this byte is taken as the difference in
intensity from the previous pixel. This difference is interpreted as an 8-bit signed
integer.
3. Repeat step 2 until all pixels have been read.
Using this data compression algorithm greatly increases the data transfer speed of the USB4000.
Compression rates of 35-48% can easily be achieved with this algorithm.
The following shows a section of a spectral line source spectrum and the results of the data
compression algorithm.
42
Pixel Value
Value
Difference
Transmitted Bytes
185
0
0x80 0x00 0xB9
2151
1966
0x80 0x08 0x67
836
-1315
0x80 0x03 0x44
453
-383
0x80 0x01 0xC5
210
-243
0x80 0x00 0xD2
118
-92
0xA4
90
-28
0xE4
89
-1
0xFF
87
-2
0xFE
89
2
0x02
86
-3
0xFD
88
2
0x02
98
10
0x0A
121
23
0x17
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USB4000 Data Sheet
Pixel Value
Value
Difference
Transmitted Bytes
383
262
0x80 0x01 0x7F
1162
779
0x80 0x04 0x8A
634
-528
0x80 0x02 0x7A
356
-278
0x80 0x01 0x64
211
-145
0x80 0x00 0xD3
132
-79
0xB1
88
-44
0xD4
83
-5
0xFB
86
3
0x03
82
-4
0xFC
91
9
0x09
92
1
0x01
81
-11
0xF5
80
-1
0xFF
84
4
0x04
84
0
0x00
85
1
0x01
83
-2
0xFE
80
-3
0xFD
80
0
0x00
88
8
0x08
94
6
0x06
90
-4
0xFC
103
13
0x0D
111
8
0x08
138
27
0x1B
In this example, spectral data for 40 pixels is transmitted using only 60 bytes. If the same data set
were transmitted using uncompressed data, it would require 80 bytes.
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USB4000 Data Sheet
Technical Note 2: USB4000 Checksum
Calculation
For all uncompressed pixel modes, the checksum is simply the unsigned 16-bit sum (ignoring
overflows) of all transmitted spectral points. For example, if the following 10 pixels are transferred,
the calculation of the checksum would be as follows:
Pixel Number
Data
(decimal)
Data (hex)
0
15
0x000F
1
23
0x0017
2
46
0x002E
3
98
0x0062
4
231
0x00E7
5
509
0x01FD
6
1023
0x03FF
7
2432
0x0980
8
3245
0x0CAD
9
1984
0x07C0
Checksum value: 0x2586
When using a data compression mode, the checksum becomes a bit more complicated. A compressed
pixel is treated as a 16-bit unsigned integer, with the most significant byte set to 0. Using the same
data set used in Technical Note 1, the following shows a section of a spectral line source spectrum and
the results of the data compression algorithm.
44
Data Value Value Difference
Transmitted Bytes
Value added to Checksum
185
0
0x80 0x00 0xB9
0x0139
2151
1966
0x80 0x08 0x67
0x08E7
836
-1315
0x80 0x03 0x44
0x03C4
453
-383
0x80 0x01 0xC5
0x0245
210
-243
0x80 0x00 0xD2
0x0152
118
-92
0xA4
0x00A4
90
-28
0xE4
0x00E4
89
-1
0xFF
0x00FF
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USB4000 Data Sheet
Data Value Value Difference
Transmitted Bytes
Value added to Checksum
87
-2
0xFE
0x00FE
89
2
0x02
0x0002
86
-3
0xFD
0x00FD
88
2
0x02
0x0002
98
10
0x0A
0x000A
121
23
0x17
0x0017
383
262
0x80 0x01 0x7F
0x01FF
1162
779
0x80 0x04 0x8A
0x050A
634
-528
0x80 0x02 0x7A
0x02FA
356
-278
0x80 0x01 0x64
0x01E4
211
-145
0x80 0x00 0xD3
0x0153
132
-79
0xB1
0x00B1
88
-44
0xD4
0x00D4
83
-5
0xFB
0x00FB
86
3
0x03
0x0003
82
-4
0xFC
0x00FC
91
9
0x09
0x0009
92
1
0x01
0x0001
81
-11
0xF5
0x00F5
80
-1
0xFF
0x00FF
84
4
0x04
0x0004
84
0
0x00
0x0000
85
1
0x01
0x0001
83
-2
0xFE
0x00FE
80
-3
0xFD
0x00FD
80
0
0x00
0x0000
88
8
0x08
0x0008
94
6
0x06
0x0006
90
-4
0xFC
0x00FC
103
13
0x0D
0x000D
111
8
0x08
0x0008
138
27
0x1B
0x001B
The checksum value is simply the sum of all entries in the last column, and evaluates to 0x2C13.
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USB4000 Data Sheet
46
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