I am trying out the MCP3911 (SSOP-20 version) as a analog front end for my Teensy 3 in power measurements and the code i am using is based on the Arduino IDE. So far, I am struggling with getting the chip to even acknowledge SPI communications, so I wanted to ask a couple of questions to help me with the diagnostics... Thank you in advance for any help!
1) Is the SPI interface de-coupled from the main system clock? The reason I ask is that I am using the maximum allowable clock crystal speed (16MHz) and wonder if that could be leading to an issue, even if the teensy can run SPI fine at 16MHz (clockdiv4 @ 48MHz CPU frequency).
2) The MCP3911 MCLK crystal has a 18pF load capacitance requirement and I am using a pair of 33pF capacitors, does that seem reasonable? (i.e. 2CL-3pF)
I would attach you the datasheet of MCP3911 http://www.kynix.com/uploadfiles/pdf2286/MCP3911A0-E2fML_70919.pdf