Issue with reading WHO AM I Register of ICM20948 over SPI with nRF52832 and Zephyr

RE: Issue with reading WHO AM I Register of ICM20948 over SPI with nRF52832 and Zephyr

Håkon Alseth — Mon, 02 Sep 2024 07:05:13 GMT

Hi,

I'm glad to hear that you got the communication up and running!

Kind regards,

Håkon

RE: Issue with reading WHO AM I Register of ICM20948 over SPI with nRF52832 and Zephyr

vimok — Sat, 31 Aug 2024 22:21:06 GMT

I made the following change and the code is working now.

Thank you for the suggestions.

void read_register(uint8_t reg, uint8_t *data, uint32_t size)
{
    int ret;

    struct spi_buf tx_buf = {
        .buf = &reg,
        .len = 1,
    };

    struct spi_buf rx_buf[] = {
        {.buf = NULL, .len = 1},
        {.buf = data, .len = size},
    };

    struct spi_buf_set tx = {.buffers = &tx_buf, .count = 1};
    struct spi_buf_set rx = {.buffers = &rx_buf, .count = ARRAY_SIZE(rx_buf)};

    ret = spi_transceive(spi_dev, &spi_cfg, &tx, &rx);
    if (ret) {
        printk("SPI read failed with error code %d\n", ret);
        return;
    }
}

RE: Issue with reading WHO AM I Register of ICM20948 over SPI with nRF52832 and Zephyr

Håkon Alseth — Thu, 30 May 2024 13:34:46 GMT

Hi,

Don't take away the sensor. Scope the pins with the sensor connected, and trace from reboot.

PS: What is your sampling rate in your logic analyzer? It looks to be 800 Hz, which is way to low of a sampling rate. You should have atleast 8 MHz (preferably 4*Fs, ie. 16 MHz)

Kind regards,

Håkon

RE: Issue with reading WHO AM I Register of ICM20948 over SPI with nRF52832 and Zephyr

vimok — Thu, 30 May 2024 12:47:18 GMT

I removed the sensor and connected the pins on logic analyser and am finding issues.

1. There is no clock signal

2. CS pin is getting high too soon

Will try to probe more and see what is going on.

RE: Issue with reading WHO AM I Register of ICM20948 over SPI with nRF52832 and Zephyr

Håkon Alseth — Wed, 29 May 2024 12:36:43 GMT

Hi,

Have you scoped the SPI signals to see how the pins behave, and if they behave as expected?

If yes, can you share the result here?

Kind regards,

Håkon