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No Response to WHO_AM_I read request on IIS328DQ

Question asked by beaster.michael on May 16, 2016

I'm trying to use a Cypress CY8C4247 microcontroller to communicate with an ST Accelerometer (IIS328DQ) and getting nowhere. I have the SPI configured for 1MHz communication, standard Motorola SPI with data captured on rising edge of clock. I've verified and re-verified my wiring between the Cypress eval board and the STEVAL-MKI170V1 (essentially just a breakout board of said device). I'm transmitting one byte of data = 0x8F (1 0 0 0 1 1 1 1) to read the 0x0F (WHO_AM_I) register. I see the data going out on the MOSI line but nothing coming back on the MISO line. I also tried configuring the CTRL_REG_1 register first to force the part to stay awake but that had no effect. In the attached screenshot, yellow is the SS, green is the CLK, red is the MOSI, and purple is the MISO. Everything looks right to me but maybe I'm missing something simple.

The only thing I noticed is that the clock is running at ~980kHz (2% error) but I wouldn't expect that to cause issues.