Logic Analyzer and I2C | LabJack
 

Logic Analyzer and I2C

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MrBobot
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Logic Analyzer and I2C

Problem:

I got a logic analyzer to log and decode the I2C transactions.  The odd thing is that the analyzer cannot decode the I2C data if Labjack is the master.

I tried it with a Beaglebone, and it "decoded" everything correctly. See attached screenshots.

The timings from the two samples are also different.  I have no idea why.

My Question:

What settings do I need to play with (either with Labjack on some LA setting) so that the logic analyzer can decode the Labjack I2C transactions?

Additional info:

T7 with the latest firmware.

SDA and SCL are on FIO3 and FIO2 respectively. 

Pull up resistors are in place on the SCL and SDA lines.

Using the I2C function on labjack, the settings are as follows:

ljm.eWriteName(handle, "I2C_SPEED_THROTTLE", 0)

ljm.eWriteName(handle, "I2C_OPTIONS",0 )

What I did was point to slave device on address 0x28, set register 0x38 to 0x00.

Decoder is set to decode 7 bit (address bit only). (8 bit with read/write bit produces similar results)

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MrBobot
MrBobot's picture
I am not sure why the

I am not sure why the recommendations were gone, but switching to EIO fixed the issue.

LabJack Support
labjack support's picture
I'm glad to hear it is

I'm glad to hear it is working for you.

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