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App Notes

Software & Driver


U6 Firmware Revision History

Firmware is available on the U6 Firmware page.

U6 Firmware Overview

These firmware files require LJSelfUpgrade V1.21 or higher in order to upgrade the U6, which is included with the labjack installer.

Change Log

1.45: Fixed a bug that was causing ALL_STATE_WRITE to affect EIOs when not masked to do so. Fixed a potential roll issue when reading the high and low 32-bits of the system timer.

Click to Expand Change Log

1.43: Fixed a bug that was causing AINs to use the settling time for the next higher resolution.

1.42: Slight improvement to timer/counter performance while simultaneously measuring AINs.

1.40: Stream will now allow differential settings on certain channels greater than sixteen.

1.39: Modified U6_Stream_ReadSample to handle extended channels. Added a function to load more than 25 stream channels. Using the LED IO type will now disable automatic LED operations. The L2L interrupt for timer 1 will no longer disable TMR3.

1.35: Analog channels 64 and above will now set the MIO lines properly. Changed the way digital IO are updated to prevent 2-10us output-high blips during startup. Added an idle check to I2C. Fixed a timing problem with 1-wire reads. Changed stream auto recover to cease operation when there is less than 1 packet worth of data in the buffer, was previously 2 packets. Added modbus feedback function (for internal testing), added modbus I2C. Attempted to eliminate errors while reading the system timer through stream. I2C will now return ACK information when only reading. Only one ack for the address will be reported, even when the address needs to be transmitted twice. Improved timer reads in stream mode.

1.26: Fixed a problem that could cause random command-response time variances. Fixed a problem that was causing the extended muxing system to control MIO lines when using special channels.

1.24: Enabled special channels though feedback IO_Type 1. Fixed a problem that was causing the analog multiplexers to not be set correctly after reading a special channel when using a resolution of 1 or above. Fixed a problem that was causing the U6 to use resolution settings one higher then requested, only affected pro resolutions (9 and above).

1.22: On startup the U6 will now clear the watchdog if invalid settings are detected. Added z-phase support to quadrature timer modes. Changed minimum watchdog timeout period to 1s. Modbus reads from 7100 will now return the timer values from timer 0 instead of timer 1. Writes to modbus addresses 6100-6122 are now supported. Added special stream channels 230-233, 240 and 241. The All state write IO type will no longer set unmasked pins to output. Added counter with debounce timer mode. Added Line-to-Line timer mode. When configuring stream for differential readings on extended channels the firmware will throw an error when the specified channel does not map to an even channel on the U6. That is, 24-31, 40-47, 56-63 etc. are invalid. Added 1-wire support. Added modbus data format check. Fixed an issue that was corrupting some data returned by modbus. The I2C function will now send the address even when no data bytes are written or read. Feedback will now throw and error when an AIN is read while stream is active. Added functions that will attempt to prevent the high-speed ADC from becoming improperly biased when the high-res converter is read. Added an option to the SPI function that allows the number of bits in the final byte transferred to be specified. Enabling a TimerClock with a divisor will now force most of the Counter0 settings off to prevent Counter0 from interfering with the USB system. None of the disabled features are needed by the TimerClock.

1.13: Disabled Auto-ranging. Added special channel support (193 etc.) to command-response functions. Extra settling will no longer be added to streams with only one channel. Fixed a problem that could cause UART to not respond to the TC pin offset. Added DSP IO_Type with functions 1-4. Fixed a problem that was causing the I2C speed parameter to not respond properly to the I2C command. When passing stream config with zero for settling delay and only one channel in the scan, settling delay will no longer be decremented to 255. Modbus related: Added out of bounds checks for DAC float conversions, using the negative channel addresses can now set differential mode, ranges above 3 will now be set to 0, improve normal converter calibration application. Changed temperature offset (see section 2.6.4) from -2.5K to -3K.

1.04: Extend analog input channel addressing has been changed to match the documentation. The upper 3 bits of the channel number were being placed on the MIO lines, instead of the lower 3 as documented.

1.03: New settling options. Added device name string. Added extended watchdog function. Added extended AIN channel support. Improved AIN reading when switching between channels. Autosettling has been updated. Upgrading to this firmware will reset the startup defaults. Stream will now determine the minimum required settling when the settling parameter is set to zero.

0.95: Feedback will now throw an error when reading counters that have not been enabled. Fixed an issue that would occasionally cause stream to incorrectly report a scan overlap. Stream start will now throw an error if the stream table is invalid or a stream is already active. Stream stop will now throw an error if stream is not running. Stream stop will now clear the USB FIFO for the stream endpoint.

0.92: Stream resolution index has been shifted to match non-streaming indices. USB has been updated to improve compatibility with Linux kernels prior to 2.6.28. Improved timer and counter functionality to run quicker. Specs pending. Added Initial Modbus support. Feedback will now allow multiple auto-range IO types per packet.

0.80: Added the new startup defaults system.




using DFe 5.84 reading LJ U6 chan 14 (internal temp sensor) at 2 sec interval average 15 w/ latest UD driver get readings of 20.5 spiking frequently to 22.0 +- C at ~20.5 C w/ firmware 1.24.

Down grading the U6 to fw 1.13 (my previous version) get straight 20.5 C +- a couple of hundreths.

conversion straight subtraction K to C.

normally run settling of 4 for this app, tried 0, etc....  Still temperature spikes all settling settings.

U6 internal ground (chan 15) (w/ fw 1.24) now doing odd things when changing settling times.


running fw 1.22...... works fine.

USB is NOT usb 2, but 1.  Hub is 2, but not on a USB 2 port on mb.

everything sent yesterday (19 Apr 2011)

fw 1.24 tried various settling times---  None corrected problem.

Have NOT changed resolution from 8.


This was resolved via email. Turned out that firmware 1.24 had several issues. Switching to firmware 1.26 solved the problem.