How to set timer delay for each of data for sending from nrf52840 to android apps ?

Question

I have followed this tutorial from this link but cannot get it work. 
 
 do
 {
 
 int i;
 
 char buf[42];
 for (i = 0; i < 3; i++) {
 snprintf(buf,42, "A%dBBCCDDEEAABBCCDDEEAABBCCDDEEAABBCCDDXX", i); 
 // puts string into buffer
 printf("%s
", buf); // outputs so you can see it

 APP_TIMER_DEF(buf);
 
 app_timer_create(&buf,APP_TIMER_MODE_REPEATED, uart_event_handle);
 app_timer_start(buf, APP_TIMER_TICKS(1000), NULL);

 
 uint16_t length2 = sizeof(buf);
 
 err_code = ble_nus_data_send(&m_nus,buf, &length2, m_conn_handle);
 


 }
 
 if ((err_code != NRF_ERROR_INVALID_STATE) &&
 (err_code != NRF_ERROR_RESOURCES) &&
 (err_code != NRF_ERROR_NOT_FOUND))
 {
 APP_ERROR_CHECK(err_code);
 }
 } while (err_code == NRF_ERROR_RESOURCES);
 
 I have 3 loop. For the first loop of sending data it will have a delay about 1s and until 2 finish. But there is no delay and it does not work.

Edvin · Accepted Answer

Hello, 
 The timer setup you use is something you haven't found in your link, right? 
 I don't know what you expect, but I suspect that you expect the app_timer_create() and app_timer_start() to delay your application for 1 sec. Unfortunately it does not. Besides, you should check the return values from the functions that return values, such as app_timer_create() and app_timer_start. You will see that these will probably not return NRF_SUCCESS, at least not the second time. 
 
 If you want to send a notification every 1000ms, you can trigger this from the interrupt handler in the timer, which looks like the uart_event_handle. You should create a separate event handler, not share it with the uart_event_handle. 
 The point of the APP_TIMER_MODE_REPEATED is that it will reset once you get the timeout event, so you should only start it once. 
 
 Look at how the app_timer is used in the ble_app_hrs example. It uses this timer to send a new battery status notification on every timeout.

ox00 · Answer

nrf_delay_ms(); Using this function solve all my problem. It sequence is in order.Both sending & receiving data get complete data.

How to set timer delay for each of data for sending from nrf52840 to android apps ?

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