nRF52832 SPI Master read results in "zeros"

[leey]

Update 1/27/2016

  Just reviewing again the pins + schematic; I am using the following pins:

         SCK     P0.07
         CS       P0.08
         MOSI   P0.06

         MISO    P0.05/AIN3


  Looing at the MISO pin, it seems this is the only one that is "different" than the other 3 pins

  Is there something else that I need to do in order to use MISO pin on P0.05/AIN3; maybe because the pin can also be used as Analog Input ?


  Thanks.

Lee

Hi,

I am interfacing nRF52832 to an ADC chip; very simple SPI interface.

I am re-using the SPI examples from SDK 12.2.0; and the SPI runs without any problem.

I can see the correct signals being generated on the SPI pins(CS, SCK, MOSI and MISO); in regards to MISO pins, I can see the ADC is sending the right bits(using a scope).

The SPI protocol requires: 1x TX byte and will receive 3 bytes of RX data.

On the scope, I can see a total of 32 SCK bits and the correct MISO data.

BUT in the output of the SPI interface APIs, the data read is all "zeros"; so 3 bytes of "0" values.

I have been double checking the codes and can't find any obvious error.

Any suggestion ?

I am attaching the scopes of the 2 pins: SCK and MISO.

Thanks for the help.

scope_3.png

Lee

[Sigurd]

As seen here, Pin P0.05 to P0.08 are by default used by the UART. Please check if you are using the UART module. If you are able to, you should also try switch to different pins to check if that solves the problem.