From 95910b32fa2a4b43f8ab9a0c0c0bdb8d2560bb6a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?King=20K=C3=A9vin?= <kingkevin@cuvoodoo.info>
Date: Tue, 15 Oct 2013 13:20:49 +0200
Subject: [PATCH] task scheduler and handlers implemented (basics)

---
 src/main.c | 138 +++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 108 insertions(+), 30 deletions(-)

diff --git a/src/main.c b/src/main.c
index ef17547..4a80470 100644
--- a/src/main.c
+++ b/src/main.c
@@ -18,19 +18,33 @@ volatile uint8_t input_i = 0; /* user input index */
 volatile uint8_t pwr_ok; /* is power ok */
 volatile uint8_t fan; /* fan signal state, to measure tachometer */
 volatile uint8_t timer2_ovf = 0; /* to measure fan speed using timer 2 */
-static const uint16_t TIMER2_PRESCALE[8] = {0,1,8,32,64,128,256,1024}; /* timer 2 CS2[2:0] values */
+uint16_t TIMER2_PRESCALE[8] = {0,1,8,32,64,128,256,1024}; /* timer 2 CS2[2:0] values */
 volatile uint16_t tachometer = 0; /* the tachometer time (from timer) */
 volatile uint8_t ir; /* IR signal state, to measure IR code */
-static const uint16_t TIMER1_PRESCALE[8] = {0,1,8,64,256,1024,0,0}; /* timer 1 CS1[2:0] values */
+uint16_t TIMER1_PRESCALE[8] = {0,1,8,64,256,1024,0,0}; /* timer 1 CS1[2:0] values */
 volatile uint16_t ir_tick; /* number of counter ticks per millisecond */
 volatile uint8_t pulse = 0; /* pulse index within the burst */
 #define PULSE_MAX 128 /* maximum number of pulses to save */
 uint16_t burst[PULSE_MAX]; /* pulse times forming a burst (from timer) */
 
+/* channel variables */
+#define LEVELS 10 /* the number of PWM levels */
+uint8_t ch_tick = 0; /* the tick counter for the channel PWM */
+#define OUTPUTS_1 5 /* the number of outputs for channel 1 */
+#define OUTPUTS_2 5 /* the number of outputs for channel 2 */
+volatile uint8_t* PORTS_1[OUTPUTS_1] = {&PORTC,&PORTC,&PORTC,&PORTC,&PORTC}; /* channel 1 output ports */
+volatile uint8_t* PORTS_2[OUTPUTS_2] = {&PORTD,&PORTD,&PORTD,&PORTD,&PORTD}; /* channel 2 output ports */
+uint8_t BITS_1[OUTPUTS_1] = {PC0,PC1,PC2,PC3,PC4}; /* channel 1 output bits */
+uint8_t BITS_2[OUTPUTS_2] = {PD2,PD3,PD4,PD5,PD7}; /* channel 2 output bits */
+uint8_t ch_1[OUTPUTS_1]; /* the level value for the channel 1 outputs */
+uint8_t ch_2[OUTPUTS_2]; /* the level value for the channel 2 outputs */
+
 /* flags, set in the interrupts and handled in the main program */
-volatile bool input_flag = false;
-volatile bool power_flag = false;
-volatile bool ir_flag = false;
+volatile bool uart_flag = false; /* an incoming activity on the UART */
+volatile bool power_flag = false; /* a change in the power or fan */
+volatile bool ir_flag = false; /* to process a burst */
+volatile bool pwm_flag = false; /* to trigger a PWM tick */
+volatile bool channel_flag = false; /* indicate a change in the channel PWM values */
 
 /* UART receive interrupt */
 ISR(USART_RX_vect) {
@@ -39,7 +53,7 @@ ISR(USART_RX_vect) {
 	if (input_i<INPUT_MAX) { /* next character, if space is available */
 		input_i++;
 	}
-	input_flag = true; /* set flag */
+	uart_flag = true; /* set flag */
 }
 
 /* power ok interrupt */
@@ -92,6 +106,12 @@ ISR(TIMER1_COMPA_vect) { /* timer 1 OCR1A match interrupt vector */
 	}
 }
 
+/* timer 0 interrupt used generate a PWM for the channels */
+ISR(TIMER0_COMPA_vect) { /* timer 0 OCR0A match interrupt vector */
+	ch_tick = (ch_tick+1)%LEVELS;
+	pwm_flag = true;
+}
+
 static void ioinit(void)
 {
 	/* configure power */
@@ -105,18 +125,7 @@ static void ioinit(void)
 
 	/* configure LED (on PD6/OC0A) */
 	DDRD |= (1<<LED); /* LED is output */
-	/* use timer 1 to produce a PWM */
-	/* use phase correct PWM mode (because fast PWM is always on for at least 1 cycle) */
-	TCCR0A &= ~(1<<WGM01);
-	TCCR0A |= (1<<WGM00);
-	TCCR0B &= ~(1<<WGM02);
-	/* /64 prescale timer */
-	TCCR0B &= ~(1<<CS02);
-	TCCR0B |= (1<<CS01)|(1<<CS00);
-	/* clear on match, because the pin is used as sink */
-	TCCR0A |= (1<<COM0A1)|(1<<COM0A0);
-	/* start with LED on */
-	OCR0A = 0xff;
+	PORTD &= ~(1<<LED); /* switch LED on */
 	
 	/* configure FAN */
 	DDRC &= ~(1<<FAN); /* FAN (PC5/PCINT13) is input */
@@ -153,8 +162,8 @@ static void ioinit(void)
 		ir_tick = F_CPU/(1000*prescale); /* ticks per ms */
 		OCR1A = (uint32_t)(15*F_CPU)/(1000*prescale); /* set clear time to 15 ms (no IR toggle should be longer) */
 	}
-	TIFR1 &= ~(1<<OCF1A); /* clear timer 1 overflow interrupt flag */
-	TIMSK1 |= (1<<OCIE1A); /* enable timer 1 overflow interrupt */
+	TIFR1 &= ~(1<<OCF1A); /* clear timer 1 compare interrupt flag */
+	TIMSK1 |= (1<<OCIE1A); /* enable timer 1 compare interrupt */
 
 	/* configure channels (used for powering LEDs using an nMOS) */
 	DDRC |= (1<<CH1_1)|(1<<CH1_2)|(1<<CH1_3)|(1<<CH1_4)|(1<<CH1_5); /* CH1_x is output */
@@ -162,6 +171,18 @@ static void ioinit(void)
 	DDRD |= (1<<CH2_1)|(1<<CH2_2)|(1<<CH2_3)|(1<<CH2_4)|(1<<CH2_5); /* CH2_x is output */
 	PORTD &= ~((1<<CH2_1)|(1<<CH2_2)|(1<<CH2_3)|(1<<CH2_4)|(1<<CH2_5)); /* switch off CH2_x */
 
+	/* use timer 0 as source for the channel PWM */
+	/* use CTC mode */
+	TCCR0A |= (1<<WGM01);
+	TCCR0A &= ~(1<<WGM00);
+	TCCR0B &= ~(1<<WGM02);
+	/* /64 prescale timer */
+	TCCR0B &= ~(1<<CS02);
+	TCCR0B |= (1<<CS01)|(1<<CS00);
+	OCR0A = 0xff; /* set PWM speed */
+	TIFR0 &= ~(1<<OCF0A); /* clear timer 0 compare interrupt flag */
+	TIMSK0 |= (1<<OCIE0A); /* enable timer 0 compare interrupt */
+
 	/* use UART as terminal */
 	uart_init();
 	stdout = &uart_output;
@@ -182,10 +203,72 @@ int main(void)
 	ir_data.command = 0;
 	uint8_t ir_repeat = 0; /* number of times the IR data has been repeated */
 
+	/* initialize channel output PWM values */
+	for (uint8_t i=0; i<OUTPUTS_1; i++) {
+		ch_1[i] = 0;
+	}
+	for (uint8_t i=0; i<OUTPUTS_2; i++) {
+		ch_2[i] = 0;
+	}
+	uint8_t on_1[5] = {0,0,0,0,0}; /* times when to switch on the outputs for channel 1 */
+	uint8_t on_2[5] = {0,0,0,0,0}; /* times when to switch on the outputs for channel 2 */
+	uint8_t off_1[5] = {0,0,0,0,0}; /* times when to switch off the outputs for channel 1 */
+	uint8_t off_2[5] = {0,0,0,0,0}; /* times when to switch off the outputs for channel 2 */
+	channel_flag = true; /* calculate above values later */
+
 	puts("LED dimmer up & running");
 	while (true) {
-		/* handle user input */
-		while (input_flag) {
+		/* calculated PWM values */
+		while (channel_flag) {
+			uint8_t start = 0;
+			for (uint8_t i=0; i<OUTPUTS_1; i++) {
+				on_1[i] = (start)%LEVELS;
+				off_1[i] = (on_1[i]+ch_1[i])%LEVELS;
+				start = (start+ch_1[i])%LEVELS;
+			}
+			start = 0;
+			for (uint8_t i=0; i<OUTPUTS_2; i++) {
+				on_2[i] = (start)%LEVELS;
+				off_2[i] = (on_2[i]+ch_2[i])%LEVELS;
+				start = (start+ch_2[i])%LEVELS;
+			}
+			channel_flag = false;
+		}
+		/* generate PWM for channel */
+		while (pwm_flag) {
+			if (pwr_ok) {
+				for (int i=0; i<OUTPUTS_1; i++) {
+					if (on_1[i]==ch_tick) {
+						if (on_1[i]!=off_1[i]) {
+							*(PORTS_1[i]) |= (1<<BITS_1[i]);
+						} else if (ch_1[i]==0) {
+							*(PORTS_1[i]) &= ~(1<<BITS_1[i]);
+						} else {
+							*(PORTS_1[i]) |= (1<<BITS_1[i]);
+						}
+					} else if (off_1[i]==ch_tick) {
+						*(PORTS_1[i]) &= ~(1<<BITS_1[i]);
+					}
+				}
+				for (int i=0; i<OUTPUTS_2; i++) {
+					if (on_2[i]==ch_tick) {
+						if (on_2[i]!=off_2[i]) {
+							*(PORTS_2[i]) |= (1<<BITS_2[i]);
+						} else if (ch_2[i]==0) {
+							*(PORTS_2[i]) &= ~(1<<BITS_2[i]);
+						} else {
+							*(PORTS_2[i]) |= (1<<BITS_2[i]);
+						}
+					} else if (off_2[i]==ch_tick) {
+						*(PORTS_2[i]) &= ~(1<<BITS_2[i]);
+					}
+				}
+				PIND |= (1<<LED);
+			}
+			pwm_flag = false;
+		}
+		/* handle UART input */
+		while (uart_flag) {
 			/* echo back */
 			char c = 0;
 			while (command_i<input_i) {
@@ -193,7 +276,7 @@ int main(void)
 				putchar(c);
 			}
 			uart_action(c);
-			input_flag = false;
+			uart_flag = false;
 		}
 		/* handle power state */
 		while (power_flag) {
@@ -264,13 +347,8 @@ static void uart_action(char c)
 			}
 			break;
 		case '1':
-			PINC |= (1<<CH1_1);
-			printf("CH1_1: ");
-			if (PINC&(1<<CH1_1)) {
-				puts("on");
-			} else {
-				puts("off");
-			}
+			ch_1[0] = (ch_1[0]+1)%(LEVELS+1);
+			channel_flag = true;
 			break;
 		case '2':
 			PINC |= (1<<CH1_2);