I'm using a custom board designed around this nRF52832 module. Testing the twi_scanner from examples of `nRF5_SDK_17.0.2_d674dde`. Built and flashed the firmware successfully (with Black Magic Probe debugger).
Problem is, the firmware doesn't log the address of the I2C device (BNO055) or *any* I2C device. Even when the slot is not populated, it does not show that "no I2C device has been found".
Here is main.c:
/** @file
* @defgroup tw_scanner main.c
* @{
* @ingroup nrf_twi_example
* @brief TWI Sensor Example main file.
*
* This file contains the source code for a sample application using TWI.
*
*/
#include <stdio.h>
#include "app_error.h"
#include "app_util_platform.h"
#include "boards.h"
#include "nrf_drv_twi.h"
#include "nrf_log.h"
#include "nrf_log_ctrl.h"
#include "nrf_log_default_backends.h"
/* TWI instance ID. */
#if TWI0_ENABLED
#define TWI_INSTANCE_ID 0
#elif TWI1_ENABLED
#define TWI_INSTANCE_ID 1
#endif
/* Number of possible TWI addresses. */
#define TWI_ADDRESSES 127
#define BOARD_CUSTOM 1
/* TWI instance. */
static const nrf_drv_twi_t m_twi = NRF_DRV_TWI_INSTANCE(TWI_INSTANCE_ID);
/**
* @brief TWI initialization.
*/
void twi_init(void) {
ret_code_t err_code;
const nrf_drv_twi_config_t twi_config = {
.scl = 11,
.sda = 10,
.frequency = NRF_DRV_TWI_FREQ_100K,
.interrupt_priority = APP_IRQ_PRIORITY_HIGH,
.clear_bus_init = false};
err_code = nrf_drv_twi_init(&m_twi, &twi_config, NULL, NULL);
APP_ERROR_CHECK(err_code);
nrf_drv_twi_enable(&m_twi);
}
/**
* @brief Function for main application entry.
*/
int main(void) {
ret_code_t err_code;
uint8_t address;
uint8_t sample_data;
bool detected_device = false;
APP_ERROR_CHECK(NRF_LOG_INIT(NULL));
NRF_LOG_DEFAULT_BACKENDS_INIT();
NRF_LOG_INFO("TWI scanner started.");
NRF_LOG_FLUSH();
twi_init();
for (address = 1; address <= TWI_ADDRESSES; address++) {
NRF_LOG_INFO("%d\n", (uint32_t) 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();
}
while (true) {
/* Empty loop. */
}
}
/** @} */
I've disabled deferred (`#define NRF_LOG_DEFERRED 0`) in config.
The code hangs specifically at this function :
err_code = nrf_drv_twi_rx(&m_twi, address, &sample_data, sizeof(sample_data));
Or more specifically, it never exits this block:
else
{
bool transmission_finished = false;
do {
if (nrf_twim_event_check(p_twim, NRF_TWIM_EVENT_SUSPENDED))
{
NRFX_LOG_DEBUG("TWIM: Event: %s.", EVT_TO_STR_TWIM(NRF_TWIM_EVENT_SUSPENDED));
transmission_finished = true;
}
if (nrf_twim_event_check(p_twim, NRF_TWIM_EVENT_STOPPED))
{
nrf_twim_event_clear(p_twim, NRF_TWIM_EVENT_STOPPED);
NRFX_LOG_DEBUG("TWIM: Event: %s.", EVT_TO_STR_TWIM(NRF_TWIM_EVENT_STOPPED));
transmission_finished = true;
}
if (nrf_twim_event_check(p_twim, NRF_TWIM_EVENT_ERROR))
{
nrf_twim_event_clear(p_twim, NRF_TWIM_EVENT_ERROR);
NRFX_LOG_DEBUG("TWIM: Event: %s.", EVT_TO_STR_TWIM(NRF_TWIM_EVENT_ERROR));
bool lasttx_triggered = nrf_twim_event_check(p_twim, NRF_TWIM_EVENT_LASTTX);
uint32_t shorts_mask = nrf_twim_shorts_get(p_twim);
if (!(lasttx_triggered && (shorts_mask & NRF_TWIM_SHORT_LASTTX_STOP_MASK)))
{
// Unless LASTTX event arrived and LASTTX_STOP shortcut is active,
// triggering of STOP task in case of error has to be done manually.
nrf_twim_task_trigger(p_twim, NRF_TWIM_TASK_RESUME);
nrf_twim_task_trigger(p_twim, NRF_TWIM_TASK_STOP);
// Mark transmission as not finished yet,
// as STOPPED event is expected to arrive.
// If LASTTX_SUSPENDED shortcut is active,
// NACK has been received on last byte sent
// and SUSPENDED event happened to be checked before ERROR,
// transmission will be marked as finished.
// In such case this flag has to be overwritten.
transmission_finished = false;
}
if (lasttx_triggered && (shorts_mask & NRF_TWIM_SHORT_LASTTX_SUSPEND_MASK))
{
// When STOP task was triggered just before SUSPEND task has taken effect,
// SUSPENDED event may not arrive.
// However if SUSPENDED arrives it always arrives after ERROR.
// Therefore SUSPENDED has to be cleared
// so it does not cause premature termination of busy loop
// waiting for STOPPED event to arrive.
nrf_twim_event_clear(p_twim, NRF_TWIM_EVENT_SUSPENDED);
// Mark transmission as not finished yet,
// for same reasons as above.
transmission_finished = false;
}
}
} while (!transmission_finished);
There are 4k7 pull-up resistors on the i2c device. I've checked with a logic analyzer. Both SDA/SCL are always high no matter what. The i2c_scanner of arduino nano detects the address.
