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introduced timer divider

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This commit is contained in:
john stone 2013-09-05 21:56:20 +02:00
parent 26bdfdd5f7
commit f57a24af06
1 changed files with 15 additions and 23 deletions
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38
firmware/lib/hal.c
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@ -10,11 +10,13 @@
static volatile uint8_t ir_active = 0; static volatile uint8_t ir_active = 0;
static volatile int16_t wait_time = 0; static volatile int16_t wait_time = 0;
static uint8_t timerdivider;
static uint8_t button_count[2]; static uint8_t button_count[2];
static uint8_t button_pressed[2]; static uint8_t button_pressed[2];
// interrupt for button handling, every 10ms // interrupt for button handling, every 10ms
ISR(TIMER2_COMPA_vect) { ISR(TIMER2_COMPA_vect,ISR_NOBLOCK) {
uint8_t i = 0; uint8_t i = 0;
for(i = 0; i < 2; ++i) { for(i = 0; i < 2; ++i) {
@ -40,15 +42,20 @@ ISR(TIMER2_COMPA_vect) {
} }
ISR(TIMER0_COMPA_vect) { ISR(TIMER0_COMPA_vect) {
// generate 38kHz signal // (2*38)kHz ISR
//
//generate 38kHz signal:
if(ir_active) { if(ir_active) {
PORTD ^= 1 << 2; PORTD ^= 1 << 2;
} }
timerdivider ++;
//quaterdivider for wait_ms
if(!(timerdivider & 0x03)) {
--wait_time;
}
// tell wait_ms() that 1/38 ms has passed
--wait_time;
} }
void init_hw(void) { void init_hw(void) {
@ -211,25 +218,10 @@ void buzzer_off(void) {
PORTC &= ~(1 << 0); PORTC &= ~(1 << 0);
} }
// uses the 76k ISR dividet by 4 -> 4 * 19 == 76
void wait_ms(uint16_t ms) { void wait_ms(uint16_t ms) {
// TODO: this function seems to be ~10% too fast wait_time = ms * (int16_t) 19;
int32_t cycles = ms * (int32_t) 76;
// wait_time is int16_t for performance reasons, so we have to wait multiple times
while(cycles >= INT16_MAX) {
cycles -= INT16_MAX;
wait_time = INT16_MAX;
while(wait_time > 0) {
test_stop_app();
}
}
// wait the odd time left
wait_time = cycles;
while(wait_time > 0) { while(wait_time > 0) {
test_stop_app(); test_stop_app();
} }