TWI slowdown with bus busy

RE: TWI slowdown with bus busy

Kazi Afroza Sultana — Fri, 08 Jul 2022 09:44:22 GMT

Hello,

Looking at your code snippet, I can not find any timeouts mechanism in the driver. Can you check the logic traces of SDA and SCL pin?

Thanks.

Best Regards,

Kazi Afroza Sultana

RE: TWI slowdown with bus busy

Stefano1984 — Tue, 28 Jun 2022 07:54:06 GMT

Hello,

The version of the SDK is 17.1.0. I use the following code to initialize the device:

void ext_twi_init(void)
{
    ret_code_t err_code;

    const nrf_drv_twi_config_t twi_config = {
       .scl                = EXT_SCL_PIN,
       .sda                = EXT_SDA_PIN,
       .frequency          = 0x00520000UL,
       .interrupt_priority = APP_IRQ_PRIORITY_HIGH,
       .clear_bus_init     = false
    };

    err_code = nrf_drv_twi_init(&m_ext_twi, &twi_config, NULL, NULL);
    APP_ERROR_CHECK(err_code);

    nrf_drv_twi_enable(&m_ext_twi);
}

then use the following functions to transmit and receive data:

uint32_t TwiTx(uint8_t address, uint8_t const * p_data, uint8_t length)
{
    ret_code_t err_code = nrf_drv_twi_tx(&m_ext_twi, address, p_data, length, false);
    APP_ERROR_CHECK(err_code);

    return err_code;
}

uint32_t ExtTwiRx(uint8_t address, uint8_t * p_data, uint8_t length)
{
    ret_code_t err_code = nrf_drv_twi_rx(&m_ext_twi, address, p_data, length);
    APP_ERROR_CHECK(err_code);

    return err_code;
}

Thanks.

Best Regards,

RE: TWI slowdown with bus busy

Kazi Afroza Sultana — Mon, 27 Jun 2022 22:28:28 GMT

Hello,

Which SDK version you are using and the code you call from the application? We also prefer to have the information of the logic trace of the pins.

Thanks.

Best Regards,

Kazi Afroza Sultana

RE: TWI slowdown with bus busy

Stefano1984 — Fri, 24 Jun 2022 07:55:47 GMT

Hello,

is it possible to reduce the timeout period?

RE: TWI slowdown with bus busy

Kazi Afroza Sultana — Fri, 24 Jun 2022 06:19:06 GMT

Hello,

TWI (M) peripheral depends on the STOP condition that should be present on the BUS in order to generate the STOPPED event for both read and write condition and to complete the transfer.
When SDA is tied to Ground (GND), it is not possible to generate the STOP condition on the bus. Therefore it causes peripheral to wait for this condition and probable outcome is timeout.

Thanks.

Best Regards,

Kazi Afroza Sultana