SPI_CR1_CPOL not working on STM32F427

[becafuel]

Hello,

I have a board that is using a F427ZIT and I want to read data from the MCP3204 chip (this is an ADC). This chip is using mode (1,1).
So, I configure my config this way :

Code: Select all

uint16_t CR1 = SPI_CR1_BR_2 | SPI_CR1_SSI | SPI_CR1_MSTR | SPI_CR1_SPE | SPI_CR1_CPOL | SPI_CR1_CPHA;
  SPIConfig spi2_cfg =
  {
     NULL,
     GPIOE,                                          /*   port of CS on Socket #2   */
     GPIOE_CS2,                                      /*   pin of CS    */
     CR1,
    0
  };

Unfortunately, here is what I get :


And here is what I should get (got this using NETMF) :


Is there something I am doing wrong ? With the SPI_CR1_CPOL bit set, the clock line should be high, to me. Here it is low.
If I try Mode (0,0) then I get values back but those are wrong.


Regards,
________
Christophe

[becafuel]

Nobody has any clue ?

[Giovanni]

You are initializing a field of a presumably constant structure using a variable.

Giovanni

[becafuel]

What is the point ? I do not understand what can go wrong with this ?

The same exact code does work on a F429 iDiscovery and if I set the value directly in the struct it does not work either on the F427 :

Code: Select all

SPIConfig spi5_cfg =
  {
     NULL,
     GPIOE,                                          /*   port of CS on Socket #2   */
     GPIOE_CS2,                                      /*   pin of CS    */
     SPI_CR1_SSI | SPI_CR1_MSTR | SPI_CR1_SPE | SPI_CR1_CPOL | SPI_CR1_CPHA,
    0
  };

[Giovanni]

Hi,

Remove this:

SPI_CR1_SSI | SPI_CR1_MSTR | SPI_CR1_SPE

The driver handles those bits internally.

Giovanni

[becafuel]

Unfortunately, this does not change anything
The clock line is still held low.

[Giovanni]

You should verify that:

1) Registers are setup as expected after spiStart().
2) That the behavior is not the expected one from the STM32 Reference Manual.

Giovanni