Other Parts Discussed in Thread: ADS1299
I have 2 ADS1299's connected to the same SPI lines, except for chip select pin. I have modified the first ADS's CONFIG1 register so it outputs a clock signal via CLK pin, and this chip's CLK_SEL pin is tied to DVDD with a 10k resistor.
The second ADS has does not have a DRDY pin, and no START pin either and it's CLK_SEL pin is tied to ground via a 10k resistor. after outputting the clock signal from the first ADS, I am trying to read registers from the second ADS, but it's not giving back correct values. I have tried turning the clock from the first ADS on and off and reading from the second ADS, which shows no difference either, except for sometime rather than showing just 0's it shows some random 1's as well.
I checked the clock and it's at 1.78 MHz, which is below what the internal oscillator should be making, but still is within the range of the required CLK frequency according to the datasheet.
I follow the process that is:
- turning device 1 CS low;
- modifying CONFIG1 so CLK is connected to device 1's oscillator;
- turning device 1 CS high;
- turning device 2 CS low;
- reading registers.
Am I missing something fundamental here?