ADS7038Q1EVM-PDK: SPI Issue

Hi Nick,

I recently worked on the ADS7038-Q1 Example C Code and I recall with no inputs connected to the ADC that I would often read all zeros due to there being no noise in the conversion results.

For a quick test to see if your SPI communication is working correctly, you might try setting the FIX_PAT bit to 1b in the DATA_CFG register. When this bit is enabled the ADC should return a fixed pattern of 0xA5A when reading data.

Best regards,
Chris

Chris, 

I am trying to read the System Status and General Cfg registers. The system status register should return 1 on a rx request. I will enable this bit in the register tomorrow when I am back in the lab to see if that is the fix. In the mean time could you confirm electrical pin out and if there is anything I am missing from the comment above? 

Thank you for the promt response, 

Nick

Hi Nick,

OK, that makes sense...

I think you may need to connect a 3.3V supply to DVDD. On the EVM, AVDD and DVDD are come from two different supplies on the PAMB board. You can share the U1 output with DVDD by connecting a wire from TP1 to TP2.

Best regards,
Chris

Not sure what you mean by TP1 and TP2. The only schematic I see is attached. Can you give a more detailed electrical connection points based on schematic below 

www.ti.com/.../sbau279.pdf

Hi Nick,

This is what I meant...

Connect the AVDD (TP1) testpoint to the DVDD (TP2) testpoint.

...Otherwise, provide a separate 3.3V supply for DVDD.

Best regards,
Chris

Okay, I will try this first thing tomorrow and let you know how it goes.