nrf_delay_ms not working?

[Robin]

Hello Nordic Pros,

Doing some debugging using RTT Viewer and an nRF51822 under SDK12.3.  Here is the code lines of interest:

...
    NRF_LOG_INFO("IPHONE 'PPM' RECEIVED @ %d mS\r\n", m_life_count_msec);
    nrf_delay_ms(2000);
    NRF_LOG_INFO("ID QUERY '?' SENT AT: %d\r\n", m_life_count_msec);
...

And here are the log messages:

iDrink::INFO:IPHONE 'PPM' RECEIVED @ 683250 mS
iDrink::INFO:ID QUERY '?' SENT AT: 683250

m_life_count_msec is a copy of an app timer count in mSec that is set up to inc ~ every 50 mSec.

Here is the timer setup code:

...
  app_timer_create(&m_app_timer_id, APP_TIMER_MODE_REPEATED, timeout_handler);  //create and start timer...
  app_timer_start(m_app_timer_id, APP_TIMER_TIMEOUT_TICKS, (void*) 0);
...

And here is the timeout code showing the assignment to m_life_count_msec:

...
void timeout_handler(void * context)
{
...
  m_life_count_msec   += APP_TIMER_MS_COUNT;
...

Obviously the questions is, why is there not a 2000 mSec delay between the two log messages?

Does nrf_delay_ms() suspend m_app_timer while it is counting?

Help, please!

Robin @ TL

[Robin]

Hello again, Kenneth, Nguyen,

So, I have made the variable "volatile"

...
static volatile uint32_t m_life_count_msec = 0;
...

I access it in a function called by the timeout handler:

...
void timeout_handler(void * context)
{
  connect_chk_count += APP_TIMER_MS_COUNT;
  board_life_chk_count += APP_TIMER_MS_COUNT;
  m_timer_msec        += APP_TIMER_MS_COUNT;
  m_counter_msec      += APP_TIMER_MS_COUNT;
  m_life_count_msec   += APP_TIMER_MS_COUNT;
  
  if (board_life_chk_count >= BOARD_LIFE_CHK_PERIOD)
  {
    board_life_chk_count = 0;
    board_life_chk();
  }
  switch (m_app_mode)
  {
    case APP_CONNECT_CHK:
      if (connect_chk_count >= 500)
      {
        connect_chk_count = 0;
        connect_check();
      }
    break;
...

I then print the variable before and after the delay using RTT Viewer:

...
void connect_check(void)
{
//    sprintf(message_buffer, "?");
//    m_send_string(message_buffer);
  static uint8_t check_count = 0;
  
  if (iphone_connect)
  {
    NRF_LOG_INFO("DELAY TEST 1: %d mSec\r\n", m_life_count_msec);
    nrf_delay_ms(2000);
    NRF_LOG_INFO("DELAY TEST 2: %d mSec\r\n", m_life_count_msec);
    NRF_LOG_INFO("IPHONE CONNECT @ %d mSec\r\n", m_life_count_msec);
    NRF_LOG_INFO("CHECK COUNT = %d\r\n", check_count);
...

Yet still, the variable is not updated while the delay is happening, (and it does appear to be happening if I manually time between the two prints:

iDrink::INFO:DELAY TEST 1: 272600 mSec
iDrink::INFO:DELAY TEST 2: 272600 mSec

So it appears that this delay function does suspend any app delay functionality while it runs.

Do you know of a way to use both functions successfully?

Thanks

Robin @ TL

[RK]

"So it appears that this delay function does suspend any app delay functionality while it runs."

No it doesn't. nrf_delay_ms() is just a dumb power wasting loop. Hence your problem lies elsewhere. 

Where are you calling connect_check() from? I'm going with Kenneth here that it's likely to be in an interrupt context, stick in a breakpoint, look at the stack, where are you, what do the CPU registers say about your context?