Hello all, I am following up on a previous question i had while using the AD7124-8 to measure multiple RTDs. Now my question is concerning the process of internal gain and offset calibration. When doing the calibration, the offset and gain registers never get updated.
1. First i enable the channel I am trying to calibrate. In this case, it is channel 0. I can read the all channels back and this is the only one enabled now.
2. I write a value of 0x800000 to the offset register (OFFSET_2 in this case since i am using SETUP 2)
3. I configure the ADC control register with the value of 0x25B (Internal Full scale calibration mode, external clock, CS_EN high, Mid power mode).
4. I have a while loop that waits for DOUT/RDY pin to go to low. Does a dummy read of the data register to bring data ready pin low.
5. I set a delay for 4 settling periods for full scale (at 10Hz, this is 1200ms)
6. I set the mode to ZS cal mode (write a 0x257 to include all the above mentioned bits and also change the mode to 0101)
7. I use the same while loop and timer.
Then i read the offset and gain registers. The gain register is all 0's and the offset register reads 0x800000. I am thinking that i am doing the calibration wrong and it doesn't write anything at all to the gain and offset registers. When i comment out my self-cal code, the ADC gets good measurements from the RTDs, albeit a little off. Does anyone have an idea on what this issue could be?