Hello, I'm having troubles using the ADC.
I'm measuring current values via a shunt and an amplificator (INA126U) which gives me an output between 0 and 1.5V (equivalent to 0 to 10A). That is the input of the ADC.
There are 2 ADC and 2 temp sensor on the SPI bus and is managed by an FPGA which as an old software written by someone I don't know.
What I see is that the output value is often doubled on the SPI whereas I know that the measure should not be (I measure it with an oscilloscope).
I'm joinning some screens from the digital analyser (picoscope) of the SPI. I would like to know if those values come from a bad SPI timing (the data is changing of the falling edge of the clock and to me, that's wrong) or something.
Or could this be from the sensor itself ?
On the screen we can see that the bit seems to be "shifted" to the left (for the one on the right).
And on this screen, we can see a "half bit".
I also noticed that when the ground of the electrical board is connected to the ground of the computer (via the picoscope), it seems to reduce this problem. Do you think the problem could be comming from EMC issue ?
Thank you in advance.
Justine