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Eddess
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April 1, 2025
Solved

LSM6DSV on STEVAL MKI239A with Nucleo board via SPI not working

  • April 1, 2025
  • 1 reply
  • 455 views

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

Eddess_0-1743493087888.png

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

Eddess_1-1743495078971.pngEddess_2-1743495176541.png

with external pull up on MISO

Eddess_5-1743495442778.png

full duplex master CPOL=1 CPHA=0

Eddess_3-1743495266676.png

with external pull up on MISO

Eddess_4-1743495321463.png

I tried in master half duplex

Eddess_7-1743495608417.pngEddess_6-1743495560968.png

with external pull up on MISO

Eddess_8-1743495684008.png

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

Eddess_9-1743495806423.png

with external pull up on MISO

Eddess_10-1743495867881.png

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

    This topic has been closed for replies.
    Best answer by gab

    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;
}

     

    1 reply

    G
    gabAnswer
    Visitor II
    April 3, 2025

    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;
}

     

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