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STM32F1: correct the read of timer master value

pull/3076/head
bcostm 2016-10-13 10:04:54 +02:00
parent 382cb9f57a
commit 8a570cce93
3 changed files with 20 additions and 14 deletions
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5
targets/TARGET_STM/TARGET_STM32F1/TARGET_BLUEPILL_F103C8/device/hal_tick.c
View File

@ -43,10 +43,9 @@ void set_compare(uint16_t count);
extern volatile uint32_t SlaveCounter;
extern volatile uint32_t oc_int_part;
extern volatile uint16_t oc_rem_part;
extern volatile uint16_t cnt_val;
void timer_irq_handler(void) {
cnt_val = TIM_MST->CNT;
uint16_t cval = TIM_MST->CNT;
TimMasterHandle.Instance = TIM_MST;
@ -68,7 +67,7 @@ void timer_irq_handler(void) {
} else {
if (oc_int_part > 0) {
set_compare(0xFFFF);
oc_rem_part = cnt_val; // To finish the counter loop the next time
oc_rem_part = cval; // To finish the counter loop the next time
oc_int_part--;
} else {
us_ticker_irq_handler();

5
targets/TARGET_STM/TARGET_STM32F1/TARGET_NUCLEO_F103RB/device/hal_tick.c
View File

@ -43,10 +43,9 @@ void set_compare(uint16_t count);
extern volatile uint32_t SlaveCounter;
extern volatile uint32_t oc_int_part;
extern volatile uint16_t oc_rem_part;
extern volatile uint16_t cnt_val;
void timer_irq_handler(void) {
cnt_val = TIM_MST->CNT;
uint16_t cval = TIM_MST->CNT;
TimMasterHandle.Instance = TIM_MST;
@ -68,7 +67,7 @@ void timer_irq_handler(void) {
} else {
if (oc_int_part > 0) {
set_compare(0xFFFF);
oc_rem_part = cnt_val; // To finish the counter loop the next time
oc_rem_part = cval; // To finish the counter loop the next time
oc_int_part--;
} else {
us_ticker_irq_handler();

24
targets/TARGET_STM/TARGET_STM32F1/us_ticker.c
View File

@ -38,7 +38,6 @@ static int us_ticker_inited = 0;
volatile uint32_t SlaveCounter = 0;
volatile uint32_t oc_int_part = 0;
volatile uint16_t oc_rem_part = 0;
volatile uint16_t cnt_val = 0;
void set_compare(uint16_t count)
{
@ -59,15 +58,24 @@ void us_ticker_init(void)
uint32_t us_ticker_read()
{
uint32_t counter;
uint32_t counter, counter2;
if (!us_ticker_inited) us_ticker_init();
//Current value of TIM_MST->CNT is stored in cnt_val and is
//updated in interrupt context
// A situation might appear when Master overflows right after Slave is read and before the
// new (overflowed) value of Master is read. Which would make the code below consider the
// previous (incorrect) value of Slave and the new value of Master, which would return a
// value in the past. Avoid this by computing consecutive values of the timer until they
// are properly ordered.
counter = (uint32_t)(SlaveCounter << 16);
counter += cnt_val;
return counter;
counter += TIM_MST->CNT;
while (1) {
counter2 = (uint32_t)(SlaveCounter << 16);
counter2 += TIM_MST->CNT;
if (counter2 > counter) {
break;
}
counter = counter2;
}
return counter2;
}
void us_ticker_set_interrupt(timestamp_t timestamp)