I have a custom sensor that returns an analog voltage. I'm planning on integrating it onboard the RTF via the ADC pins on an 80 pin I/O expansion connection that is hooked up to the compute board. Now I'm struggling on the software side: how do I access these sensor readings from the compute board?
Thank you for contacting Intel Customer Support.
Check out the link below and let me know if it is helpful for you.
if you have any further questions, don't hesitate to contact me.
Yes, I've been referencing that page of the wiki. I'm able to interact with the gpio pins in "/sys/class/gpio", however I can't find the analog pins -- there is no directory "/sys/class/analog". Where can this analog data be accessed?
The FPGA_ADC4 pin is the only ADC pin exposed on the 80-pin accessories cable. You will need to flash the FPGA with a different jam file than the standard one that routes the FPGA_ADC4 to the pin. I am currently checking if we have one available and will get back to you soon. Once the FPGA is configured, you can access the adc value with SPI calls as mentioned in the following document: https://github.com/intel-aero/meta-intel-aero/wiki/95-(References)-FPGA
Thank you for looking into the new JAM file.
Is there any other way that you would suggest getting sensor data onboard the drone so that it can be accessed via software (on the compute board OR flight controller)? Perhaps by converting the analog measurements to digital using an auxiliary chip and then routing the digital data into the "telemetry" pins? Any ideas are greatly appreciated!