Slave address read unexpectedly in TWI

RE: Slave address read unexpectedly in TWI

alex kim — Tue, 22 Oct 2019 07:40:48 GMT

Sorry.

There was a hardware mistake.

RE: Slave address read unexpectedly in TWI

Einar Thorsrud — Mon, 05 Aug 2019 06:17:31 GMT

Hi,

I am having a bit of problem seeing how you do things in the second (non-working) case, where you use non-blocking transfers. Where do you print the "TWI device detected at address xx" in that case? The code you have posted is just for the first case (which is working as expected from what I understand).

RE: Slave address read unexpectedly in TWI

alex kim — Fri, 02 Aug 2019 00:54:44 GMT

#include <stdint.h>
#include <string.h>
#include "nordic_common.h"
#include "nrf.h"
#include "ble_hci.h"
#include "ble_advdata.h"
#include "ble_advertising.h"
#include "ble_conn_params.h"
#include "nrf_sdh.h"
#include "nrf_sdh_soc.h"
#include "nrf_sdh_ble.h"
#include "nrf_ble_gatt.h"
#include "nrf_ble_qwr.h"
#include "app_timer.h"
#include "ble_nus.h"
#include "app_uart.h"
#include "app_util_platform.h"
#include "bsp_btn_ble.h"
#include "nrf_pwr_mgmt.h"

#if defined (UART_PRESENT)
#include "nrf_uart.h"
#endif
#if defined (UARTE_PRESENT)
#include "nrf_uarte.h"
#endif

#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"

#include "nrf_drv_saadc.h"
#include "nrf_drv_twi.h"

void twi_handler(nrf_drv_twi_evt_t const * p_event, void * p_context)
{
    switch (p_event->type)
    {
        case NRF_DRV_TWI_EVT_DONE:
            if (p_event->xfer_desc.type == NRF_DRV_TWI_XFER_RX)
            {
//                data_handler(m_sample);
            }
            m_xfer_done = true;
            break;
        default:
            break;
    }
}

/**
 * @brief TWI initialization.
 */
void twi_init (void)
{
    ret_code_t err_code;

    const nrf_drv_twi_config_t twi_config = {
       .scl                = 16,		//ARDUINO_SCL_PIN,
       .sda                = 17,		//ARDUINO_SDA_PIN,
       .frequency          = NRF_DRV_TWI_FREQ_400K,
       .interrupt_priority = APP_IRQ_PRIORITY_HIGH,
       .clear_bus_init     = false
    };

    err_code = nrf_drv_twi_init(&m_twi, &twi_config, NULL, NULL);
//    err_code = nrf_drv_twi_init(&m_twi, &twi_config, twi_handler, NULL);	
    APP_ERROR_CHECK(err_code);

    nrf_drv_twi_enable(&m_twi);
}

int main(void)
{
    bool erase_bonds;

    // Initialize.
     uart_init();
	
    log_init();
    timers_init();
	cat_timers_init();
	saadc_init();
	
    twi_init();
	
	#define TWI_ADDRESSES	127
	ret_code_t err_code;
	uint8_t detected_device = 0;
	uint8_t sample_data;
    for (uint8_t address = 1; address <= TWI_ADDRESSES; address++)
    {
        err_code = nrf_drv_twi_rx(&m_twi, address, &sample_data, sizeof(sample_data));
        if (err_code == NRF_SUCCESS)
        {
            detected_device = true;
            NRF_LOG_INFO("TWI device detected at address 0x%x.", address);
        }
        NRF_LOG_FLUSH();
    }

    if (!detected_device)
    {
        NRF_LOG_INFO("No device was found.");
        NRF_LOG_FLUSH();
    }
    ICM20602_whoAmI();
	ICM20602_init();
	
    buttons_leds_init(&erase_bonds);
	gpio_led_init();	
    power_management_init();
    ble_stack_init();
    gap_params_init();
    gatt_init();
    services_init();
    advertising_init();
    conn_params_init();

    // Start execution.
    NRF_LOG_INFO("Debug logging for UART over RTT started.");
    advertising_start();
	cat_timers_start();
	
    // Enter main loop.
    for (;;)
    {
        idle_state_handle();
    }
}

RE: Slave address read unexpectedly in TWI

awneil — Thu, 01 Aug 2019 09:41:57 GMT

RE: Slave address read unexpectedly in TWI

alex kim — Thu, 01 Aug 2019 01:01:34 GMT

Hi, awneil

1. I used the following code to detect the TWI address of the Slave

for (address = 1; address <= TWI_ADDRESSES; address++)
{
err_code = nrf_drv_twi_rx(&m_twi, address, &sample_data, sizeof(sample_data));
if (err_code == NRF_SUCCESS)
{
detected_device = true;
NRF_LOG_INFO("TWI device detected at address 0x%x.", address);
}
NRF_LOG_FLUSH();
}

2. my scl and sda were connected to p16 and p17

3. twi_init()

1) ret_code_t ret = nrf_drv_twi_init(&m_twi, &twi_config, NULL, NULL);

The slave address is detected as 0x68. It is normal.

2) ret_code_t ret = nrf_drv_twi_init(&m_twi, &twi_config, twi_handler, NULL);

void twi_handler(nrf_drv_twi_evt_t const * p_event, void * p_context)
{
switch (p_event->type)
{
case NRF_DRV_TWI_EVT_DONE:
if (p_event->xfer_desc.type == NRF_DRV_TWI_XFER_RX)
{
data_handler(m_sample);
}
m_xfer_done = true;
break;
default:
break;
}
}

0> <info> app: TWI device detected at address 0x1.
 0> <info> app: TWI device detected at address 0x5.
 0> <info> app: TWI device detected at address 0x8.
 0> <info> app: TWI device detected at address 0xB.
 0> <info> app: TWI device detected at address 0xE.
 0> <info> app: TWI device detected at address 0x12.
 0> <info> app: TWI device detected at address 0x15.
 0> <info> app: TWI device detected at address 0x18.
 0> <info> app: TWI device detected at address 0x1B.
 0> <info> app: TWI device detected at address 0x1E.

A strange slave address is detected.
0x68 is not visible

Best Regards,

Alex

RE: Slave address read unexpectedly in TWI

awneil — Wed, 31 Jul 2019 11:47:29 GMT

[quote userid="69031" url="~/f/nordic-q-a/50442/slave-address-read-unexpectedly-in-twi"]read the slave address in TWI[/quote]

That doesn't make sense!

You don't read the Slave Address in I2C (aka TWI).

You send the Slave address to identify which slave should respond.

I think you need to review how I2C works:

Here is the I2C Specification: https://www.nxp.com/docs/en/user-guide/UM10204.pdf

https://en.wikipedia.org/wiki/I%C2%B2C

etc, ...