Hi,
I'm using the nRF51 dongle with nRF SDK 12.3.0 and the S130 2.0.1 SoftDevice to implement a BLE central. The dongle repeatedly connects to a BLE peripheral, performs some tests, then disconnects.
I am using the app_timer module to delay some actions in the tests to test different scenarios. In total I have three single-shot timers, for which I call app_timer_create at startup, and then app_timer_start/app_timer_stop repeatedly. During a test run, I do not always use all three of them, but at the end I call app_timer_stop on all of them.
err_code = app_timer_create(&m_timer1, APP_TIMER_MODE_SINGLE_SHOT, timer1_handler);
APP_ERROR_CHECK(err_code);
err_code = app_timer_create(&m_timer2, APP_TIMER_MODE_SINGLE_SHOT, timer2_handler);
APP_ERROR_CHECK(err_code);
err_code = app_timer_create(&m_timer3, APP_TIMER_MODE_SINGLE_SHOT, timer3_handler);
APP_ERROR_CHECK(err_code);
... later ...
NRF_LOG_DEBUG("Will wait %d ms before doing xxx\n", m_xxx_delay_ms);
err_code = app_timer_start(m_timer2,
APP_TIMER_TICKS(m_xxx_delay_ms, APP_TIMER_PRESCALER), ctx);
APP_ERROR_CHECK(err_code);
For some reason, the timing is completely off. The timers take way too long to fire, in the order of seconds. I am new to nRF5 development, and started off using the heart rate sample. The app_timer module is initialized like so:
APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_OP_QUEUE_SIZE, NULL);
with APP_TIMER_OP_QUEUE_SIZE set to 5. Not sure if this is the right value. I saw that there was an config macro for profiling, but I am unsure what it does and how it would help me. At least I don't see any NRF_LOG output when I activate it.
Another thing I am observing and believe that it's probably related, is the following: i use app_timer_cnt_get() and app_timer_cnt_diff_compute() to compute the elapsed time since the BLE connection was established:
static int elapsed_ms_since_connected() {
uint32_t ticks_since_connected;
app_timer_cnt_diff_compute(app_timer_cnt_get(), m_connection_established_ticks, &ticks_since_connected);
return (ticks_since_connected * 1000) / APP_TIMER_CLOCK_FREQ;
}
m_connection_established_ticks is set using app_timer_cnt_get() when the BLE_GAP_EVT_CONNECTED event is received. I then print these values out over NRF_LOG, and they are completely wrong too.
Have I misconfigured the timer somehow? How do I go about debugging this issue?
Many thanks in advance, Alex
