Posted on December 15, 2016 at 20:52Got an old code for STM8L151 related to delay implementation, in case it gives some clues...
////////////////////////////////////////////////////
// These functions use TIM3 to measure elapsed time
#define TIME_CHUNK 1000
void NOPs(u16 loop) {
while(loop--) _asm('nop\n');
}
void Wait_us(u32 time_us) {
// the max time_us is 1000, if more than this, we slice it in 1000 pieces
u32 delay;
while(time_us) {
if(time_us<5)
time_us = 5; // smallest delay time allowed
if(time_us>TIME_CHUNK)
delay = TIME_CHUNK;
else
delay = time_us;
Set_Countdown(delay);
while(!Countdown_Over()) ;
time_us = time_us - delay;
}
return;
// Set_Countdown(time_us);
// while(!Countdown_Over()) ;
}
void Wait_ms(u16 time_ms)
{
while(time_ms--)
Wait_us(1000);
}
//~~~~ function body
void Init_Countdown(void) {
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CLK_PeripheralClockConfig(CLK_Peripheral_TIM3, ENABLE);
TIM3_TimeBaseInit(TIM3_Prescaler_16,TIM3_CounterMode_Up, 65535 ); // make a 1us clock unit for timer
TIM3_OC1Init(TIM3_OCMode_Timing,TIM3_OutputState_Disable,0x0000,TIM3_OCPolarity_High,TIM3_OCIdleState_Reset);
// the second one is to measure in 50 msec unit
TIM3_OC2Init(TIM3_OCMode_Timing,TIM3_OutputState_Disable,0x0000,TIM3_OCPolarity_High,TIM3_OCIdleState_Reset);
TIM3_Cmd(ENABLE);
Set_Countdown2(50000); // to start later the first tick
}
void Set_Countdown(u32 time_us) {
u16 capture;
//disableInterrupts();
TIM3_ClearFlag(TIM3_FLAG_CC1);
// start the timer and main loop will wait for flag
capture = TIM3_GetCounter();
// here put the conversion from us to timer_ticks
TIM3_SetCompare1(capture + time_us);
//enableInterrupts();
}
u8 Countdown_Over(void) {
if (TIM3_GetFlagStatus(TIM3_FLAG_CC1) != RESET)
{
TIM3_ClearFlag(TIM3_FLAG_CC1);
return TRUE;
};
return FALSE;
}
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 50 msec version
void Set_Countdown2(u32 time_us) {
u16 capture;
// Timer countdown is 'duration'
if(time_us==0)
return;
// convert us to timer count : 1 us = 64 counts ==>
time_us = time_us * 1; //64; // before PLL was x16, now PLL is x9 (slowed down clock speed)
// overflow at 65536 <=> 932 us, so we break down the total time by 500 us blocks
TIM3_ClearFlag(TIM3_FLAG_CC2);
// start the timer and main loop will wait for flag
capture = TIM3_GetCounter();
// here put the conversion from us to timer_ticks
TIM3_SetCompare2(capture + time_us);
}
u8 Countdown2_Over(void) {
if (TIM3_GetFlagStatus(TIM3_FLAG_CC2) != RESET)
{
TIM3_ClearFlag(TIM3_FLAG_CC2);
return TRUE;
};
return FALSE;
}
u8 Poll_For_50msec_elapsed(void) {
if(Countdown2_Over()==TRUE)
{
Set_Countdown2(50000); // 50 msec
return TRUE;
}
return FALSE;
}
