Commit 899ce952 authored by Jan Kasprzak's avatar Jan Kasprzak
Browse files

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.
parent 280768d8

projects/step-up/lights.h

+2 −2
Original line number Original line Diff line number Diff line
@@ -4,7 +4,7 @@ 
#define TESTING_FW 1

#define TESTING_FW 1





#define N_LEDS 7

#define N_LEDS 7

#define N_PWMLEDS 3

#define N_PWMLEDS 2

#define N_PWMLED_MODES 4

#define N_PWMLED_MODES 4





#define N_BUTTONS 2

#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

 * 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

 * 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 init_pwm();

void susp_pwm();

void susp_pwm();

void pwm_off(unsigned char n);

void pwm_off(unsigned char n);

projects/step-up/pwm.c

+13 −36
Original line number Original line Diff line number Diff line
@@ -7,7 +7,7 @@ 




#define PWM_STEP_SHIFT 2 /* sub-LSB precision */

#define PWM_STEP_SHIFT 2 /* sub-LSB precision */

#define PWM_TOP (((PWM_MAX) + (4 << (PWM_STEP_SHIFT))) >> (PWM_STEP_SHIFT))

#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

#error PWM_TOP too high

#endif

#endif
@@ -37,26 +37,17 @@ void init_pwm() 




	enable_pll();

	enable_pll();





	// PWM channel D is inverted, ...

	TCCR1 = _BV(CTC1) | _BV(CS10);	// no clock prescaling

	TCCR1C = _BV(COM1D1) | _BV(COM1D0) | _BV(PWM1D);

	GTCCR = _BV(COM1A1) | _BV(COM1B1) | _BV(PWM1A) | _BV(PWM1B);

	// PWM channels A and B are not

	TCCR1A = _BV(COM1A1) | _BV(COM1B1) | _BV(PWM1A) | _BV(PWM1B);

	TCCR1D = 0;

	TCCR1B = _BV(CS10); 			// no clock prescaling





	TC1H = PWM_TOP >> 8;

	OCR1C = PWM_TOP;

	OCR1C = PWM_TOP & 0xFF;				// TOP value

	OCR1A = OCR1B = 0;		// initial stride is 0





	TC1H = PWM_TOP >> 8;		// PWM3 is inverted

	DDRB  &= ~(_BV( PB1 ) | _BV( PB4 )); // tristate it

	OCR1D = PWM_TOP & 0xFF;

	PORTB &= ~(_BV( PB1 ) | _BV( PB4 )); // set to zero



	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

}

}





#if 0

void susp_pwm()

void susp_pwm()

{

{

	unsigned char i;

	unsigned char i;
@@ -71,6 +62,7 @@ void susp_pwm() 




	PLLCSR &= ~(_BV(PLLE) | _BV(PCKE));

	PLLCSR &= ~(_BV(PLLE) | _BV(PCKE));

}

}

#endif





void pwm_off(unsigned char n)

void pwm_off(unsigned char n)

{

{
@@ -79,35 +71,21 @@ void pwm_off(unsigned char n) 




		switch (n) {

		switch (n) {

		case 0: DDRB &= ~_BV(PB1); break;

		case 0: DDRB &= ~_BV(PB1); break;

		case 1: DDRB &= ~_BV(PB3); break;

		case 1: DDRB &= ~_BV(PB4); break;

		case 2: DDRB &= ~_BV(PB5); break;

		}

		}

	}

	}

}

}





static void pwm_update_hw(unsigned char n)

static void pwm_update_hw(unsigned char n)

{

{

	unsigned char hi, lo;

	uint16_t stride = (pwm[n] + step) >> PWM_STEP_SHIFT;

	uint16_t stride = (pwm[n] + step) >> PWM_STEP_SHIFT;





	if (n == 2)

		stride = PWM_TOP - stride;



	hi = stride >> 8;

	lo = stride & 0xFF;



	switch (n) {

	switch (n) {

	case 0:

	case 0:

		TC1H = hi;

		OCR1A = stride;

		OCR1A = lo;

		break;

		break;

	case 1:

	case 1:

		TC1H = hi;

		OCR1B = stride;

		OCR1B = lo;

		break;

	case 2:

		TC1H = hi;

		OCR1D = lo;

		break;

		break;

	}

	}

}

}
@@ -124,8 +102,7 @@ void pwm_set(unsigned char n, uint16_t stride) 




		switch(n) {

		switch(n) {

		case 0: DDRB |= _BV(PB1); break;

		case 0: DDRB |= _BV(PB1); break;

		case 1: DDRB |= _BV(PB3); break;

		case 1: DDRB |= _BV(PB4); break;

		case 2: DDRB |= _BV(PB5); break;

		}

		}

	}

	}

}

}