/**@brief Function for updating the Capture Compare register.
*/
static void compare_reg_update(app_timer_id_t timer_id_head_old)
{
// Setup the timeout for timers on the head of the list
if (m_timer_id_head != TIMER_NULL)
{
uint32_t ticks_to_expire = mp_nodes[m_timer_id_head].ticks_to_expire;
uint32_t counter = rtc1_counter_get();
uint32_t cc = m_ticks_latest;
uint32_t ticks_elapsed = ticks_diff_get(counter, cc) + RTC_COMPARE_OFFSET_MIN;
if (timer_id_head_old == TIMER_NULL)
{
// No timers were already running, start RTC
rtc1_start();
}
cc += (ticks_elapsed < ticks_to_expire) ? ticks_to_expire : ticks_elapsed;
cc &= MAX_RTC_CNT;
rtc1_compare0_set(cc);
if (ticks_diff_get(rtc1_counter_get(), counter) > ticks_diff_get(cc, counter))
{
timer_timeouts_check_sched();
}
}
else
{
// No timers are running, stop RTC
rtc1_stop();
}
}
void us_ticker_init(void)
{
if (us_ticker_inited) {
return;
}
rtc1_start();
us_ticker_inited = true;
}
/**@brief Function for updating the Capture Compare register.
*/
static void compare_reg_update(timer_node_t * p_timer_id_head_old)
{
// Setup the timeout for timers on the head of the list
if (mp_timer_id_head != NULL)
{
uint32_t ticks_to_expire = mp_timer_id_head->ticks_to_expire;
uint32_t pre_counter_val = rtc1_counter_get();
uint32_t cc = m_ticks_latest;
uint32_t ticks_elapsed = ticks_diff_get(pre_counter_val, cc) + RTC_COMPARE_OFFSET_MIN;
if (!m_rtc1_running)
{
// No timers were already running, start RTC
rtc1_start();
}
cc += (ticks_elapsed < ticks_to_expire) ? ticks_to_expire : ticks_elapsed;
cc &= MAX_RTC_COUNTER_VAL;
rtc1_compare0_set(cc);
uint32_t post_counter_val = rtc1_counter_get();
if (
(ticks_diff_get(post_counter_val, pre_counter_val) + RTC_COMPARE_OFFSET_MIN)
>
ticks_diff_get(cc, pre_counter_val)
)
{
// When this happens the COMPARE event may not be triggered by the RTC.
// The nRF51 Series User Specification states that if the COUNTER value is N
// (i.e post_counter_val = N), writing N or N + 1 to a CC register may not trigger a
// COMPARE event. Hence the RTC interrupt is forcefully pended by calling the following
// function.
rtc1_compare0_set(rtc1_counter_get()); // this should prevent CC to fire again in the background while the code is in RTC-ISR
nrf_delay_us(MAX_RTC_TASKS_DELAY);
timer_timeouts_check_sched();
}
}
else
{
#if (APP_TIMER_KEEPS_RTC_ACTIVE == 0)
// No timers are running, stop RTC
rtc1_stop();
#endif //(APP_TIMER_KEEPS_RTC_ACTIVE == 0)
}
}
/**@brief Function for updating the Capture Compare register.
*/
static void compare_reg_update(app_timer_id_t timer_id_head_old)
{
// Setup the timeout for timers on the head of the list
if (m_timer_id_head != TIMER_NULL)
{
uint32_t ticks_to_expire = mp_nodes[m_timer_id_head].ticks_to_expire;
uint32_t pre_counter_val = rtc1_counter_get();
uint32_t cc = m_ticks_latest;
uint32_t ticks_elapsed = ticks_diff_get(pre_counter_val, cc) + RTC_COMPARE_OFFSET_MIN;
if (timer_id_head_old == TIMER_NULL)
{
// No timers were already running, start RTC
rtc1_start();
}
cc += (ticks_elapsed < ticks_to_expire) ? ticks_to_expire : ticks_elapsed;
cc &= MAX_RTC_COUNTER_VAL;
rtc1_compare0_set(cc);
uint32_t post_counter_val = rtc1_counter_get();
if (
(ticks_diff_get(post_counter_val, pre_counter_val) + RTC_COMPARE_OFFSET_MIN)
>
ticks_diff_get(cc, pre_counter_val)
)
{
// When this happens the COMPARE event may not be triggered by the RTC.
// The nRF51 Series User Specification states that if the COUNTER value is N
// (i.e post_counter_val = N), writing N or N+1 to a CC register may not trigger a
// COMPARE event. Hence the RTC interrupt is forcefully pended by calling the following
// function.
timer_timeouts_check_sched();
}
}
else
{
// No timers are running, stop RTC
rtc1_stop();
}
}
uint32_t app_timer_init(uint32_t prescaler,
uint8_t max_timers,
uint8_t op_queues_size,
void * p_buffer,
app_timer_evt_schedule_func_t evt_schedule_func)
{
int i;
// Check that buffer is correctly aligned
if (!is_word_aligned(p_buffer))
{
return NRF_ERROR_INVALID_PARAM;
}
// Check for NULL buffer
if (p_buffer == NULL)
{
return NRF_ERROR_INVALID_PARAM;
}
// Stop RTC to prevent any running timers from expiring (in case of reinitialization)
rtc1_stop();
m_evt_schedule_func = evt_schedule_func;
// Initialize timer node array
m_node_array_size = max_timers;
mp_nodes = (timer_node_t *) p_buffer;
for (i = 0; i < max_timers; i++)
{
mp_nodes[i].state = STATE_FREE;
mp_nodes[i].is_running = false;
}
// Skip timer node array
p_buffer = &((uint8_t *)p_buffer)[max_timers * sizeof(timer_node_t)];
// Initialize users array
m_user_array_size = APP_TIMER_INT_LEVELS;
mp_users = (timer_user_t *) p_buffer;
// Skip user array
p_buffer = &((uint8_t *)p_buffer)[APP_TIMER_INT_LEVELS * sizeof(timer_user_t)];
// Initialize operation queues
for (i = 0; i < APP_TIMER_INT_LEVELS; i++)
{
timer_user_t * p_user = &mp_users[i];
p_user->first = 0;
p_user->last = 0;
p_user->user_op_queue_size = op_queues_size;
p_user->p_user_op_queue = (timer_user_op_t *) p_buffer;
// Skip operation queue
p_buffer = &((uint8_t *)p_buffer)[op_queues_size * sizeof(timer_user_op_t)];
}
m_timer_id_head = TIMER_NULL;
m_ticks_elapsed_q_read_ind = 0;
m_ticks_elapsed_q_write_ind = 0;
NVIC_ClearPendingIRQ(SWI0_IRQn);
NVIC_SetPriority(SWI0_IRQn, SWI0_IRQ_PRI);
NVIC_EnableIRQ(SWI0_IRQn);
rtc1_init(prescaler);
rtc1_start();
m_ticks_latest = rtc1_counter_get();
return NRF_SUCCESS;
}