bissen21/Marlin_Firmware
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Fix timer comments

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This commit is contained in:
Scott Lahteine
2016-10-09 10:06:31 -05:00
parent a448cedbc5
commit 3752d9aca8
2 changed files with 39 additions and 10 deletions
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25
Marlin/temperature.cpp
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@ -1371,7 +1371,7 @@ void Temperature::set_current_temp_raw() {
* Timer 0 is shared with millies so don't change the prescaler.
*
* This ISR uses the compare method so it runs at the base
* frequency (16 MHz / 256 = 62500 Hz), but at the TCNT0 set
* frequency (16 MHz / 64 / 256 = 976.5625 Hz), but at the TCNT0 set
* in OCR0B above (128 or halfway between OVFs).
*
* - Manage PWM to all the heaters and fan
@ -1485,9 +1485,16 @@ void Temperature::isr() {
#endif
#endif
// 488.28 Hz (or 1:976.56, 2:1953.12, 3:3906.25, 4:7812.5, 5:7812.5 6:15625, 6:15625 7:31250)
// SOFT_PWM_SCALE to frequency:
//
// 0: 16000000/64/256/128 = 7.6294 Hz
// 1: / 64 = 15.2588 Hz
// 2: / 32 = 30.5176 Hz
// 3: / 16 = 61.0352 Hz
// 4: / 8 = 122.0703 Hz
// 5: / 4 = 244.1406 Hz
pwm_count += _BV(SOFT_PWM_SCALE);
pwm_count &= 0x7f;
pwm_count &= 0x7F;
#else // SLOW_PWM_HEATERS
@ -1586,10 +1593,18 @@ void Temperature::isr() {
#endif
#endif //FAN_SOFT_PWM
// SOFT_PWM_SCALE to frequency:
//
// 0: 16000000/64/256/128 = 7.6294 Hz
// 1: / 64 = 15.2588 Hz
// 2: / 32 = 30.5176 Hz
// 3: / 16 = 61.0352 Hz
// 4: / 8 = 122.0703 Hz
// 5: / 4 = 244.1406 Hz
pwm_count += _BV(SOFT_PWM_SCALE);
pwm_count &= 0x7f;
pwm_count &= 0x7F;
// increment slow_pwm_count only every 64 pwm_count circa 65.5ms
// increment slow_pwm_count only every 64 pwm_count (e.g., every 8s)
if ((pwm_count % 64) == 0) {
slow_pwm_count++;
slow_pwm_count &= 0x7f;