Hi Jack,
According to your using AFE5809EVM and controlling SPI using different test board.
We tested AFE5809EVM and measured the EVM converting USB bus to 8-pin data to control SPI and other signals.
These 8-pin data (from USB on EVM) are: SEN, SCLK, SDATA, SPI_DIG_EN, PDN_ADC, PDN_VCA, PDN_GLOBAL and CDCM_LE
Here are our connections using Oscilloscope:
SEN (connected to Scope CH1)
SCLK (connected to Scope CH2)
SDATA (connected to Scope CH3)
The following plots keep CH1, CH2 and CH3 connections without any change.
Only CH4 is connected to different signal pin as below:
SPI_DIG_EN (connected to Scope CH4) = HI, please see the following
RESET (connected to Scope CH4) = LO, please see the following
PDN_ADC (connected to Scope CH4) = LO, please see the following
PDN_VCA (connected to Scope CH4) = LO, please see the following
PDN_GLOBAL (connected to Scope CH4) = LO, please see the following
CDCM_LE (connected to Scope CH4) = HI, please see the following
Please check if you can see the SPI data from your test board works similarly.
Thank you!
Best Regards,
Chen