razzor
/
dmx8chan
1
0
Fork 0
Code Issues Pull Requests Releases Activity

precalc outputvalues

This commit is contained in:
Olaf Rempel 2006-05-28 14:14:13 +02:00
parent 02b6e08279
commit 18612d804c
1 changed files with 24 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

45
dmx8chan.c
View File

@ -27,53 +27,56 @@
// channel values // channel values
volatile uint8_t chan[8] = { 0xFF, 0xFE, 0x80, 0x40, 0x20, 0x10, 0x01, 0x00 }; volatile uint8_t chan[8] = { 0xFF, 0xFE, 0x80, 0x40, 0x20, 0x10, 0x01, 0x00 };
// rx variables // rx receive variables
static uint16_t rx_chan; static uint16_t rx_chan;
static uint16_t my_base; static uint16_t my_base;
// next OCR1 value // timer variables
static uint8_t cnt; static uint8_t cnt;
static uint16_t pwm_load; static uint16_t pwm_next;
static uint8_t out_next;
/* /* Timer 1 Overflow (every 10ms) */
* Timer 1 Overflow (every 10ms)
* - reload 10ms
* - schedule compare match in 40us
*/
ISR(SIG_OVERFLOW1) ISR(SIG_OVERFLOW1)
{ {
TCNT1 = TIMER1_RELOAD; TCNT1 = TIMER1_RELOAD;
OCR1A = (TIMER1_RELOAD + TIMER1_STEP); OCR1A = (TIMER1_RELOAD + TIMER1_STEP);
pwm_load = (TIMER1_RELOAD + (TIMER1_STEP * 2));
pwm_next = (TIMER1_RELOAD + (TIMER1_STEP * 2));
cnt = 0x00; cnt = 0x00;
} }
/* /*
* Timer 1 Compare Match (every 40us) * Timer 1 Compare Match (every 40us)
* - schedule next compare match in 40us * asap:
* - set PWM Outputs (PORTB) * - schedule next compare match
* - set PWM Outputs
* interruptible:
* - calc next compare match
* - calc next output values
*/ */
ISR(SIG_OUTPUT_COMPARE1A) ISR(SIG_OUTPUT_COMPARE1A)
{ {
OCR1A = pwm_load; OCR1A = pwm_next;
pwm_load += TIMER1_STEP; PORTB = out_next;
/* rest can be interrupted by DMX receive */
sei();
pwm_next += TIMER1_STEP;
if (cnt == 0x00)
out_next = 0x00;
cnt--; cnt--;
uint8_t out = PORTB;
if (cnt == 0xFF)
out = 0x00;
uint8_t i, shift = 1; uint8_t i, shift = 1;
uint8_t *tmp = chan; volatile uint8_t *tmp = chan;
for (i = 0; i < 8; i++) { for (i = 0; i < 8; i++) {
if (*tmp++ >= cnt) if (*tmp++ >= cnt)
out |= shift; out_next |= shift;
shift <<= 1; shift <<= 1;
} }
PORTB = out;
} }
/* /*