Blocking & Non-Blocking operations on TWI

Question

Hello, 
 
 I am using nRF52832, SDK_15.3.0, S132 SoftDevice and Segger for flashing the image. I am using ‘ble_app_blinky’. 
 
 I connected my sensor to nRF52832 DK over TWI. When ‘twi_scanner’ example code loaded I received the address of the slave device. 
 Just to crosscheck I ported ‘twi_scanner’ as is into ‘ble_app_blinky’. Even here it worked fine. 
 
 1) But later I have gone through ‘twi_senor’ example and changed 
 From : nrf_drv_twi_init(&m_twi, &twi_config, NULL , NULL); 
 To : nrf_drv_twi_init(&m_twi, &twi_config, twi_handler , NULL); 
 When ‘twi_handler’ added, I get success for all 127 address. I am not sure why this happened. 
 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) Under ‘ nrf_drv_twi_init ’ for event handler it is mentioned as “If NULL, blocking mode is enabled”. What does it mean. 
 
 Thanks & Regards 
 Vishnu Beema

Øyvind · Accepted Answer

beemavishnu said: Yes, in ble_app_blinky, I mixed both 'twi_scanner' to read the address and 'twi_sensor' to add twi handler. 
 Ok, thanks! 
 beemavishnu said: If 'twi_scanner' example is blocking mode, then can I assume 'twi_sensor' as non-blocking mode. But still due to 'while (m_xfer_done == false)' whether 'twi_sensor' code will behave as a blocking mode. Please correct me if I am wrong. 
 TWI_sensor is considered as a non-blocking example since it uses a twi_handler, at least the twi driver is configured as non-blocking. However, I agree that the example is confusing when adding the flag m_xfer_done , when polling this flag the example could potentially be blocking. 
 Hope this clears some confusion. Kind regards, Øyvind

Blocking & Non-Blocking operations on TWI

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