LSM6DSV on STEVAL MKI239A with Nucleo board via SPI not working

[Eddess]

hello

I've been trying to use the LSM6DSV on it's steval-mki239a board with a nucleo board (nucleo-l476rg) via SPI and the lsm6dsv is not answering whatever the configuration of my SPI is.

The sensor is fine since it work with the steval-mki109v3 board ans the MEMS studio

I checked the SPI signal on the steval mki109v3 with a logical analyzer and found several odd things but the sensor is answering

I don't know if it is my analyzer but the MISO line is always stuck at 1 and the level of MOSI are strange but the sensor understand the message and answer with the right value (WHO_AM_I register:  MOSI should send 0x0F and MISO answer 0x70)

On the other end I tried to recreate the same configuration on my nucleo board but the sensor doesn't answer any command

I tried:

full duplex master CPOL=1 CPHA=1

with external pull up on MISO

full duplex master CPOL=1 CPHA=0

with external pull up on MISO

I tried in master half duplex

with external pull up on MISO

I tried master half duplex with CPHA =0 (1 edge)

with external pull up on MISO

I've been trying to make this work for more than a week now and tried all possible configuration but nothing works. what could be wrong? did I miss something?

I'm using the LSM6DSV library found here https://github.com/STMicroelectronics/lsm6dsv-pid/tree/7b98628713090244cf14f54d9059938cb00342fd that I adapted following the readme file

I attached my complete project

[gab · Accepted solution]

Hi @Eddess,

Your problem here is in the implementation you made of the function platform_read.

Your implementation must first send the register you want to read and then receive a response but if you want the lsm6dsv to know that you want a response you must set the MSB of the register to 1 as stated in documentation.

Exemple :

static int32_t platform_read(void *handle, uint8_t reg, uint8_t *bufp, uint16_t len){
  reg |= 0x80; // Don't forget this line !
  HAL_GPIO_WritePin(CS_up_GPIO_Port, CS_up_Pin, GPIO_PIN_RESET);
  HAL_SPI_Transmit(handle, &reg, 1, 1000);
  HAL_SPI_Receive(handle, bufp, len, 1000);
  HAL_GPIO_WritePin(CS_up_GPIO_Port, CS_up_Pin, GPIO_PIN_SET);
  return 0;
}