From: Jan "Yenya" Kasprzak Date: Thu, 25 Apr 2013 14:24:31 +0000 (+0200) Subject: pwm.c: modified for ATtiny45/step-up X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?a=commitdiff_plain;h=899ce95294ad696dbd04e2f5722fbbc00f9dec2e;p=tinyboard.git pwm.c: modified for ATtiny45/step-up So far two PWM channels OC1A/OC1B with sub-LSB resolution possible (but unused yet) using timer IRQ. TODO: get rid of OCR1C register and let it count to 255. --- diff --git a/projects/step-up/lights.h b/projects/step-up/lights.h index 772613a..986ffcb 100644 --- a/projects/step-up/lights.h +++ b/projects/step-up/lights.h @@ -4,7 +4,7 @@ #define TESTING_FW 1 #define N_LEDS 7 -#define N_PWMLEDS 3 +#define N_PWMLEDS 2 #define N_PWMLED_MODES 4 #define N_BUTTONS 2 @@ -36,7 +36,7 @@ void timer_start_slow_adcs(); * A/D converter frequency (125 kHz). Note that this is not the Top * value of T/C 1, it is shifted by PWM_STEP_SHIFT as described in pwm.c */ -#define PWM_MAX 0x780 +#define PWM_MAX 0x340 void init_pwm(); void susp_pwm(); void pwm_off(unsigned char n); diff --git a/projects/step-up/pwm.c b/projects/step-up/pwm.c index b472273..85d6c68 100644 --- a/projects/step-up/pwm.c +++ b/projects/step-up/pwm.c @@ -7,7 +7,7 @@ #define PWM_STEP_SHIFT 2 /* sub-LSB precision */ #define PWM_TOP (((PWM_MAX) + (4 << (PWM_STEP_SHIFT))) >> (PWM_STEP_SHIFT)) -#if PWM_TOP > 0x3FF +#if PWM_TOP > 0x0FF #error PWM_TOP too high #endif @@ -37,26 +37,17 @@ void init_pwm() enable_pll(); - // PWM channel D is inverted, ... - TCCR1C = _BV(COM1D1) | _BV(COM1D0) | _BV(PWM1D); - // PWM channels A and B are not - TCCR1A = _BV(COM1A1) | _BV(COM1B1) | _BV(PWM1A) | _BV(PWM1B); - TCCR1D = 0; - TCCR1B = _BV(CS10); // no clock prescaling + TCCR1 = _BV(CTC1) | _BV(CS10); // no clock prescaling + GTCCR = _BV(COM1A1) | _BV(COM1B1) | _BV(PWM1A) | _BV(PWM1B); - TC1H = PWM_TOP >> 8; - OCR1C = PWM_TOP & 0xFF; // TOP value + OCR1C = PWM_TOP; + OCR1A = OCR1B = 0; // initial stride is 0 - TC1H = PWM_TOP >> 8; // PWM3 is inverted - OCR1D = PWM_TOP & 0xFF; - - TC1H = 0x00; - OCR1B = OCR1A = 0; // initial stride is 0 - - DDRB &= ~(_BV( PB1 ) | _BV( PB3 ) | _BV( PB5 )); // tristate it - PORTB &= ~(_BV( PB1 ) | _BV( PB3 ) | _BV( PB5 )); // set to zero + DDRB &= ~(_BV( PB1 ) | _BV( PB4 )); // tristate it + PORTB &= ~(_BV( PB1 ) | _BV( PB4 )); // set to zero } +#if 0 void susp_pwm() { unsigned char i; @@ -71,6 +62,7 @@ void susp_pwm() PLLCSR &= ~(_BV(PLLE) | _BV(PCKE)); } +#endif void pwm_off(unsigned char n) { @@ -79,35 +71,21 @@ void pwm_off(unsigned char n) switch (n) { case 0: DDRB &= ~_BV(PB1); break; - case 1: DDRB &= ~_BV(PB3); break; - case 2: DDRB &= ~_BV(PB5); break; + case 1: DDRB &= ~_BV(PB4); break; } } } static void pwm_update_hw(unsigned char n) { - unsigned char hi, lo; uint16_t stride = (pwm[n] + step) >> PWM_STEP_SHIFT; - if (n == 2) - stride = PWM_TOP - stride; - - hi = stride >> 8; - lo = stride & 0xFF; - switch (n) { case 0: - TC1H = hi; - OCR1A = lo; + OCR1A = stride; break; case 1: - TC1H = hi; - OCR1B = lo; - break; - case 2: - TC1H = hi; - OCR1D = lo; + OCR1B = stride; break; } } @@ -124,8 +102,7 @@ void pwm_set(unsigned char n, uint16_t stride) switch(n) { case 0: DDRB |= _BV(PB1); break; - case 1: DDRB |= _BV(PB3); break; - case 2: DDRB |= _BV(PB5); break; + case 1: DDRB |= _BV(PB4); break; } } }