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/* This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
/* This is the main part of the LED light controller program.
 * It handles all peripherals (power, fan, channels, IR, serial)
 */
/* This program is specifically designed for hardware version A,
 * with schematic revision 2, and layout revision 5.
 */
#include <stdint.h> /* Standard Integer Types */
#include <stdio.h> /* Standard IO facilities */
#include <stdlib.h> /* General utilities */
#include <stdbool.h> /* Boolean */
#include <string.h> /* Strings */
#include <avr/io.h> /* AVR device-specific IO definitions */
#include <util/delay.h> /* Convenience functions for busy-wait delay loops */
#include <avr/interrupt.h> /* Interrupts */
#include <avr/wdt.h> /* Watchdog timer handling */
#include <avr/pgmspace.h> /* Program Space Utilities */

#include "main.h"
#include "uart.h"
#include "ir_nec.h"
#include "settings.h"

/* help strings */
const char help_00[] PROGMEM = "commands:\n";
const char help_01[] PROGMEM = "\thelp                       display this help\n";
const char help_02[] PROGMEM = "\treset                      reset boad and settings\n";
const char help_03[] PROGMEM = "\tpower                      show power state\n";
const char help_04[] PROGMEM = "\tpower on                   switch power on\n";
const char help_05[] PROGMEM = "\tpower off                  switch power off\n";
const char help_06[] PROGMEM = "\tfan                        show fan speed\n";
const char help_07[] PROGMEM = "\ttemp                       show temperature\n";
const char help_08[] PROGMEM = "\tmode                       show current mode\n";
const char help_09[] PROGMEM = "\tmode N                     select mode\n";
const char help_10[] PROGMEM = "\tch X Y                     show channel [1-2].[1-5] brightness\n";
const char help_11[] PROGMEM = "\tch X Y Z                   set channel [1-2].[1-5] brightness [0-255]\n";
const char help_12[] PROGMEM = "\tir learn power             learn the IR command to power on/off\n";
const char help_13[] PROGMEM = "\tir learn mode              learn the IR command to change between modes\n";
const char help_14[] PROGMEM = "\tir learn brightness up     learn the IR command to increase brightness\n";
const char help_15[] PROGMEM = "\tir learn brightness down   learn the IR command to decrease brightness\n";
const char help_16[] PROGMEM = "\tir learn channel next      learn the IR command to select next channel\n";
const char help_17[] PROGMEM = "\tir learn channel previous  learn the IR command to select previous channel\n";
PGM_P const help_table[] PROGMEM = {
	help_00,
	help_01,
	help_02,
	help_03,
	help_04,
	help_05,
	help_06,
	help_07,
	help_08,
	help_09,
	help_10,
	help_11,
	help_12,
	help_13,
	help_14,
	help_15,
	help_16,
	help_17
};

//volatile uint8_t* PORTS[CHANNELS_1+CHANNELS_2] = {&PORTC,&PORTC,&PORTC,&PORTC,&PORTC,&PORTD,&PORTD,&PORTD,&PORTD,&PORTD};
volatile uint8_t* PORTS[CHANNELS_1+CHANNELS_2] = {&PORTC,&PORTC,&PORTC,&PORTD,&PORTD,&PORTD};
//volatile uint8_t* DDRS[CHANNELS_1+CHANNELS_2] = {&DDRC,&DDRC,&DDRC,&DDRC,&DDRC,&DDRD,&DDRD,&DDRD,&DDRD,&DDRD};
volatile uint8_t* DDRS[CHANNELS_1+CHANNELS_2] = {&DDRC,&DDRC,&DDRC,&DDRD,&DDRD,&DDRD};
//const uint8_t BITS[CHANNELS_1+CHANNELS_2] = {PC0,PC1,PC2,PC3,PC4,PD2,PD3,PD4,PD5,PD7};
const uint8_t BITS[CHANNELS_1+CHANNELS_2] = {PC0,PC1,PC2,PD2,PD3,PD4};

/* global variables */
#define INPUT_MAX 255 /* max length for user input string */
char input[INPUT_MAX+2]; /* user input from USART */
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 through the tachometer using timer 2 */
const 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 */
const 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 */
volatile uint8_t ch_tick = 0; /* to tick for the channel PWM */
uint8_t on[CHANNELS_1+CHANNELS_2]; /* at which tick turn the channel on */
uint8_t off[CHANNELS_1+CHANNELS_2]; /* at which tick turn the channel off */

/* flags, set in the interrupts and handled in the main program */
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 channel_flag = false; /* indicate a change in the channel PWM values */
volatile bool learn_flag = false; /* learn an IR command for an action */
enum IR_ACTIONS to_learn = IR_ACTION_END; /* IR action to learn */

/* save the UART input into a string */
ISR(USART_RX_vect) { /* UART receive interrupt */
	input[input_i] = getchar(); /* save input */
	input[input_i+1] = 0; /* always end the string */
	if (input_i<INPUT_MAX) { /* next character, if space is available */
		input_i++;
	}
	uart_flag = true; /* set flag */
}

/* power ok and IR interrupt
 * store the new power start
 * save the pulse time
 */
ISR(PCINT0_vect) { /* PCI0 Interrupt Vector for PCINT[7:0] */
	if (pwr_ok!=(PINB&(1<<PWR_OK))) { /* did the PWR_OK pin state changed */
		pwr_ok = PINB&(1<<PWR_OK); /* save new state */
		power_flag = true;
	} else if (ir!=(PINB&(1<<IR))) { /* did the IR pin state changed */
		ir = PINB&(1<<IR); /* save new state */
		if (pulse>0) { /* save pulse, except the first */
			burst[pulse-1] = (TCNT1*1000UL)/ir_tick; /* pulse time in µs */
			burst[pulse] = 0; /* end the burst with 0 */
		}
		if (pulse<PULSE_MAX-1) { /* prepare to save next pulse */
			pulse++;
		}
		TCNT1 = 0; /* clear timer 1 */
	}
}

/* fan tachometer interrupt */
ISR(PCINT1_vect) { /* PCI0 Interrupt Vector for PCINT[14:8] */
	if (fan!=(PINC&(1<<FAN))) { /* did the FAN pin state changed */
		fan = PINC&(1<<FAN); /* save new state */
		if (fan) { /* only react to rising edge */
			tachometer = (uint16_t)(timer2_ovf<<8)+TCNT2; /* save time */
			TCNT2 = 0; /* reset timer 2 */
			timer2_ovf = 0; /* reset timer 2 */
		}
	}
}

/* timer 2 interrupt used to measure fan speed based on tachometer */
ISR(TIMER2_OVF_vect) { /* timer 2 overflow interrupt vector */
	if (timer2_ovf<0xff) { /* prevent overflow */
		timer2_ovf++; /* increase tachometer counter */
	} else { /* timeout for tachometer (the tachometer counter should be reseted before this timeout if the fan is on) */
		tachometer = 0; /* indicate no speed can be measured */
		if (pwr_ok) { /* warn the fan is dead while the power in on */
			power_flag = true;
		}
		timer2_ovf = 0; /* reset the tachometer counter */
	}
}

/* end of IR burst (using a timeout) */
ISR(TIMER1_COMPA_vect) { /* timer 1 OCR1A match interrupt vector */
	if (pulse>0 && !ir_flag) { /* warm a burst is ready to be processed */
		ir_flag = true;
	}
}

/* generate a PWM for the channel outputs
 * this is a bit long for an interrupt, but it's time critical
 */
ISR(TIMER0_COMPA_vect) { /* timer 0 OCR0A match interrupt vector */
	ch_tick++;
	if (pwr_ok) { /* only generate PWM if power is on */
		for (int i=0; i<CHANNELS_1+CHANNELS_2; i++) { /* generate PWM for every channel */
			if (on[i]==ch_tick) { /* time to switch on */
				if (on[i]!=off[i]) { /* switch on */
					*(PORTS[i]) |= (1<<BITS[i]);
				} else if (brightness[mode][i]==0) { /* switch off if it's also the off time and the brightness is 0 */
					*(PORTS[i]) &= ~(1<<BITS[i]);
				} else { /* switch on if it's also the off time and the brightness is full */
					*(PORTS[i]) |= (1<<BITS[i]);
				}
			} else if (off[i]==ch_tick && brightness[mode][i]!=0xff) { /* time to switch off */
				*(PORTS[i]) &= ~(1<<BITS[i]);
			}
		}
	}
}

/* disable watchdog when booting */
void wdt_init(void) __attribute__((naked)) __attribute__((section(".init3")));
void wdt_init(void)
{
	MCUSR = 0;
	wdt_disable();

	return;
}

void ioinit(void)
{
	/* configure power */
	DDRB |= (1<<nPS_ON); /* nPS_ON is output */
	PORTB |= (1<<nPS_ON); /* switch off power supply */
	DDRB &= ~(1<<PWR_OK); /* PWR_ON (PB1/PCINT1) is input */
	pwr_ok = PINB&(1<<PWR_OK); /* save state */
	PCIFR &= ~(1<<PCIF0); /* clear interrupt flag */
	PCICR |= (1<<PCIE0); /* enable interrupt for PCINT[7:0] */
	PCMSK0 |= (1<<PCINT1); /* enable interrupt for PCINT1 */

	/* configure LED (on PD6/OC0A) */
	DDRD |= (1<<LED); /* LED is output */
	PORTD &= ~(1<<LED); /* switch LED on */
	
	/* configure FAN */
	DDRC &= ~(1<<FAN); /* FAN (PC5/PCINT13) is input */
	fan = PINC&(1<<FAN); /* save state */
	PCIFR &= ~(1<<PCIF1); /* clear interrupt flag */
	PCICR |= (1<<PCIE1); /* enable interrupt for PCINT[14:8] */
	PCMSK1 |= (1<<PCINT13); /* enable interrupt for PCINT1 */
	/* use timer 2 to measure the tachometer */
	/* use normal mode */
	TCCR2A &= ~((1<<WGM20)|(1<<WGM21));
	TCCR2B &= ~(1<<WGM22);
	/* clock/64 prescaler */
	TCCR2B |= (1<<CS22);
	TCCR2B &= ~((1<<CS21)|(1<<CS20));
	TIFR2 = (1<<TOV2); /* clear timer 2 overflow interrupt flag */
	TIMSK2 |= (1<<TOIE2); /* enable timer 2 overflow interrupt */

	/* configure IR receiver */
	DDRB &= ~(1<<IR); /* IR (PB0/PCINT0) receiver is input */
	ir = PINB&(1<<IR); /* save state */
	PCIFR = (1<<PCIF0); /* clear interrupt flag */
	PCICR |= (1<<PCIE0); /* enable interrupt for PCINT[7:0] */
	PCMSK0 |= (1<<PCINT0); /* enable interrupt for PCINT0 */
	/* use timer 1 to measure IR pulse */
	/* use CTC mode */
	TCCR1A &= ~((1<<WGM10)|(1<<WGM11));
	TCCR1B |= (1<<WGM12);
	TCCR1B &= ~(1<<WGM13);
	/* clock/8 prescaler, offers most precision for 15ms (up to 28.5ms) */
	TCCR1B |= (1<<CS11);
	TCCR1B &= ~((1<<CS12)|(1<<CS10));
	uint16_t prescale = TIMER1_PRESCALE[(TCCR1B&((1<<CS12)|(1<<CS11)|(1<<CS10)))>>CS10]; /* timer 1 presacler */
	if (0!=prescale) {
		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 compare interrupt flag */
	TIMSK1 |= (1<<OCIE1A); /* enable timer 1 compare interrupt */

	/* configure channels (used for powering LEDs using an nMOS) */
	for (uint8_t i=0; i<CHANNELS_1+CHANNELS_2; i++) {
		*(DDRS[i]) |= (1<<BITS[i]);
		*(PORTS[i]) &= ~(1<<BITS[i]);
	}

	/* use timer 0 as source for the channel PWM */
	/* use CTC mode */
	TCCR0A |= (1<<WGM01);
	TCCR0A &= ~(1<<WGM00);
	TCCR0B &= ~(1<<WGM02);
	/* /8 prescale timer */
	TCCR0B &= ~(1<<CS02);
	TCCR0B |= (1<<CS01);
	TCCR0B &= ~(1<<CS00);
	OCR0A = 0x40; /* set PWM frequency (with prescale=8, 0x00=2304kHz-0xff=9kHz) */
	TIFR0 = (1<<OCF0A); /* clear timer 0 compare interrupt flag */
	TIMSK0 |= (1<<OCIE0A); /* enable timer 0 compare interrupt */

	/* configure internal temperature sensor */
	ADMUX |= (1<<REFS1)|(1<<REFS0); /* select internal 1.1V voltage reference */
	/* select ADC8 internal temperature sensor */
	ADMUX |= (1<<MUX3);
	ADMUX &= ~((1<<MUX2)|(1<<MUX1)|(1<<MUX0));
	ADCSRA |= (1<<ADEN); /* enable ADC */
	ADCSRA |= ((1<<ADPS2)|(1<<ADPS1)|(1<<ADPS0)); /* prescaler at 128 */
	/* continuously do the conversion (then don't wait for ADCS to clear) */
	//ADCSRB &= ~((1<<ADTS2)|(1<<ADTS1)|(1<<ADTS0)); /* free-running mode */
	//ADCSRA |= (1<<ADATE); /* conversion can be triggered */
	//ADCSRA |= (1<<ADSC); /* start analogue to digital conversion */
	
	/* use UART as terminal */
	uart_init();
	stdout = &uart_output;
	stdin  = &uart_input;

	sei(); /* enable interrupts */
}

void help(void)
{
	char* str;
	for (uint8_t i=0; i<sizeof(help_table)/sizeof(PGM_P); i++) { /* display all help lines */
		str = malloc(strlen_PF((uint_farptr_t)pgm_read_word(&(help_table[i]))));
		strcpy_PF(str, (uint_farptr_t)pgm_read_word(&(help_table[i])));
		printf(str);
		free(str);
	}
}

int main(void)
{
	ioinit(); /* initialize IOs */

	uint8_t command_i = 0; /* command index */
	/* last IR data */
	struct nec ir_data;
	ir_data.valid = false;
	ir_data.repeat = false;
	ir_data.address = 0;
	ir_data.command = 0;
	uint8_t ir_repeat = 0; /* number of times the IR data has been repeated */

	puts("LED dimmer up & running");

	/* load (or initialize) settings */
	if (!verify_settings()) {
		initialize_settings();
		save_settings();
		if (!verify_settings()) {
			puts("can't store setting");
			return 0;
		}
		puts("settings created");
	} else {
		load_settings();
		puts("settings loaded");
	}
	channel_flag = true; /* calculate channel values later */
	
	/* switch power supply as saved */
	if (power) {
		PORTB &= ~(1<<nPS_ON);
	} else {
		PORTB |= (1<<nPS_ON);
	}

	PORTD &= ~(1<<LED); /* switch on LED */
	while (true) {
		/* calculated PWM values (on/off times) */
		while (channel_flag) {
			/* the next channel goes on/starts when the previous goes off, so to distribute the power over the whole range, instead of only using a lot of it in the beginning */
			uint8_t start = 0;
			for (uint8_t i=0; i<CHANNELS_1+CHANNELS_2; i++) {
				on[i] = start;
				start += brightness[mode][i];
				off[i] = start;
			}
			channel_flag = false;
		}
		/* handle UART input */
		while (uart_flag) {
			PORTD |= (1<<LED); /* switch off LED */
			/* echo back */
			char c = 0;
			while (command_i<input_i) {
				c = input[command_i++];
				putchar(c);
			}
			/* detect end of line */
			if ('\n'==c || '\r'==c) {
				if ('\r'==c) { /* display new line */
					puts("");
				}
				/* process user command */
				if (command_i>1) {
					input[command_i-1] = '\0';
					uart_action(input);
					save_settings();
				}
				input_i = command_i = 0; /* reset input buffer */
			}
			uart_flag = false;
			PORTD &= ~(1<<LED); /* switch on LED */
		}
		/* handle power state */
		while (power_flag) {
			if (pwr_ok) {
				puts("power ok");
				power = 1;
				/* verify if FAN is present */
				_delay_ms(500);
				if (0==tachometer) {
					puts("FAN not on, switching power off");
					PORTB |= (1<<nPS_ON);
					power = 0;
				}
			} else {
				puts("power off");
				for (uint8_t i=0; i<CHANNELS_1+CHANNELS_2; i++) { /* switch off output */
					*(PORTS[i]) &= ~(1<<BITS[i]);
				}
				power = 0;
			}
			save_settings();
			power_flag = false;
		}
		/* handle IR input */
		while (ir_flag) {
			PORTD |= (1<<LED); /* switch off LED */
			time2nec(burst,pulse-1); /* convert raw time burst in NEC format */
			struct nec ir_tmp = nec2data(burst,pulse-1); /* decode NEC burst */
			if (ir_tmp.valid) {
				if (ir_tmp.repeat) {
					if (ir_repeat<0xff) {
						ir_repeat++;
					}
				} else {
					ir_data = ir_tmp;
					ir_repeat = 0;
				}
				if (ir_repeat==0 || ir_repeat>3) { /* process command if new or repeated */
					if (learn_flag) { /* learn command */
						if (to_learn<IR_ACTION_END) {
							ir_keys[to_learn][0] = ir_data.address;
							ir_keys[to_learn][1] = ir_data.command;
						}
						puts("IR code learned");
						to_learn = IR_ACTION_END;
						learn_flag = false;
					} else { /* trigger action */
						ir_action(ir_data.address,ir_data.command);
					}
					save_settings();
				}
			}
			pulse = 0; /* reset burst */
			ir_flag = false;
			PORTD &= ~(1<<LED); /* switch on LED */
		}
	}
	return 0;
}

void uart_action(char* str)
{
	/* split command */
	const char* delimiter = " ";
	char* word = strtok(str,delimiter);
	if (!word) {
		goto error;
	}
	/* parse command */
	if (0==strcmp(word,"help")) {
		help();
	} else if (0==strcmp(word,"reset")) {
		reset_settings();
		/* reset using watchdog */
		do {
			wdt_enable(WDTO_15MS);
			for(;;) {}
		} while(0);
	} else if (0==strcmp(word,"power")) {
		word = strtok(NULL,delimiter);
		if (!word) {
			if (PINB&(1<<nPS_ON)) {
				puts("power is off");
			} else {
				puts("power is on");
			}
		} else if (0==strcmp(word,"on")) {
			PORTB &= ~(1<<nPS_ON);
		} else if (0==strcmp(word,"off")) {
			PORTB |= (1<<nPS_ON);
		} else {
			goto error;
		}
	} else if (0==strcmp(word,"fan")) {
		if (tachometer) {
			uint16_t prescale = TIMER2_PRESCALE[TCCR2B&((1<<CS22)|(1<<CS21)|(1<<CS20))];
			if (prescale) {
				if (timer2_ovf<0xff) {
					uint32_t speed = ((60*F_CPU)/(prescale*(uint32_t)tachometer))/2; /* calculate speed. 2 pulses per revolution */
					printf("fan speed: %lurpm\n",speed);
				} else {
					printf("fan is off (or not detected)\n");
				}
			} else {
				printf("fan speed measurement not started\n");
			}
		} else {
			printf("fan is off (or not detected)\n");
		}
	} else if (0==strcmp(word,"temp")) {
		ADCSRA |= (1<<ADSC); /* start analogue to digital conversion */
		loop_until_bit_is_clear(ADCSRA,ADSC); /* wait until conversion is finished */
		printf("temperature: %u°C\n",(uint16_t)((ADCW-T_OFFSET)*T_FACTOR));
	} else if (0==strcmp(word,"mode")) {
		word = strtok(NULL,delimiter);
		if (!word) {
			printf("%u/%u\n",mode+1,MODES);
		} else {
			/* expecting one digit mode N */
			if (strlen(word)!=1) {
				goto error;
			}
			/* expecting mode 1-MODES */
			if (word[0]<'1') {
				goto error;
			}
			uint8_t mode_temp = word[0]-'1';
			if (mode_temp>MODES) {
				goto error;
			}
			mode = mode_temp;
			channel_flag = true;
		}
	} else if (0==strcmp(word,"ir")) {
		word = strtok(NULL,delimiter);
		if (0==strcmp(word,"learn")) {
			word = strtok(NULL,delimiter);
			if (0==strcmp(word,"power")) {
				to_learn = POWER;
				learn_flag = true;
			} else if (0==strcmp(word,"mode")) {
				to_learn = MODE;
				learn_flag = true;
			} else if (0==strcmp(word,"brightness")) {
				word = strtok(NULL,delimiter);
				if (0==strcmp(word,"up")) {
					to_learn = BRIGHTNESS_UP;
					learn_flag = true;
				} else if (0==strcmp(word,"down")) {
					to_learn = BRIGHTNESS_DOWN;
					learn_flag = true;
				} else {
					goto error;
				}
			} else if (0==strcmp(word,"channel")) {
				word = strtok(NULL,delimiter);
				if (0==strcmp(word,"next")) {
					to_learn = CHANNEL_NEXT;
					learn_flag = true;
				} else if (0==strcmp(word,"previous")) {
					to_learn = CHANNEL_PREVIOUS;
					learn_flag = true;
				} else {
					goto error;
				}
			} else {
				goto error;
			}
		} else {
			goto error;
		}
	} else if (0==strcmp(word,"ch")) {
		word = strtok(NULL,delimiter);
		if (!word) { /* expecting channel group */
			goto error;
		}
		if (strlen(word)!=1) { /* expecting one digit channel group X */
			goto error;
		}
		uint8_t group = 0;
		switch (word[0]) { /* expecting channel group X 1 or 2 */
			case '1':
				group = 0;
				break;
			case '2':
				group = 1;
				break;
			default:
				goto error;
		}
		/* get channel output */
		word = strtok(NULL,delimiter);
		if (!word) {
			goto error;
		}
		/* expecting one digit channel output Y */
		if (strlen(word)!=1) {
			goto error;
		}
		/* expecting channel group Y 1-CHANNELS_X */
		if (word[0]<'1') {
			goto error;
		}
		uint8_t output = word[0]-'1';
		if (group==0 && output>CHANNELS_1) {
			goto error;
		} else if (group==1 && output>CHANNELS_2) {
			goto error;
		}
		uint8_t channel = group*CHANNELS_1+output;
		/* brightness setting */
		word = strtok(NULL,delimiter);
		if (!word) {
			printf("%u\n",brightness[mode][channel]);
		} else {
			if (strlen(word)>3) {
				goto error;
			}
			uint16_t br = atoi(word);
			if (br>0xff) {
				goto error;
			}
			brightness[mode][channel] = (uint8_t)br;
			channel_flag = true;
		}
	} else {
		goto error;
	}

	if (learn_flag) {
		puts("press button on remote to learn code");
	}
	return;
error:
	puts("command not recognized");
}

void ir_action(uint8_t address, uint8_t command)
{
	enum IR_ACTIONS ir_code = IR_ACTION_END;
	static uint8_t channel = CHANNELS_1+CHANNELS_2;
	uint8_t step = 0xff/LEVELS; /* the brightness increase/decrease steps */
	for (ir_code=0; ir_code<IR_ACTION_END; ir_code++) { /* find the action for the current command */
		if (ir_keys[ir_code][0]==address && ir_keys[ir_code][1]==command) {
			break;
		}
	}
	if (ir_code<IR_ACTION_END) { /* process action */
		switch (ir_code) {
			case POWER:
				printf("switching power supply ");
				if (PINB&(1<<nPS_ON)) {
					puts("on");
				} else {
					puts("off");
				}
				PINB |= (1<<nPS_ON);
				break;
			case MODE:
				mode = (mode+1)%MODES;
				printf("selecting mode %u/%u\n",mode+1,MODES);
				channel_flag = true;
				break;
			case BRIGHTNESS_UP:
				if (channel<CHANNELS_1+CHANNELS_2) {
					if (brightness[mode][channel]<0xff-step) {
						brightness[mode][channel] += step;
					} else {
						brightness[mode][channel] = 0xff;
					}
					printf("increasing brightness ch %u %u: %u\n",(channel/CHANNELS_1)+1,(channel%CHANNELS_1)+1,brightness[mode][channel]);
				} else if (channel==CHANNELS_1+CHANNELS_2) { /* increase all brightness if no channel is selected */
					for (uint8_t i=0; i<CHANNELS_1+CHANNELS_2; i++) {
						if (brightness[mode][i]<0xff-step) {
							brightness[mode][i] += step;
						} else {
							brightness[mode][i] = 0xff;
						}
					}
					printf("increasing brightness all channels\n");
				}
				channel_flag = true;
				break;
			case BRIGHTNESS_DOWN:
				if (channel<CHANNELS_1+CHANNELS_2) {
					if (brightness[mode][channel]>step) {
						brightness[mode][channel] -= step;
					} else {
						brightness[mode][channel] = 0x00;
					}
					printf("decreasing brightness ch %u %u: %u\n",(channel/CHANNELS_1)+1,(channel%CHANNELS_1)+1,brightness[mode][channel]);
				} else if (channel==CHANNELS_1+CHANNELS_2) { /* decrease all brightness if no channel is selected */
					for (uint8_t i=0; i<CHANNELS_1+CHANNELS_2; i++) {
						if (brightness[mode][i]>step) {
							brightness[mode][i] -= step;
						} else {
							brightness[mode][i] = 0x00;
						}
					}
					printf("decreasing brightness all channels\n");
				}
				channel_flag = true;
				break;
			case CHANNEL_NEXT:
				if (channel<=CHANNELS_1+CHANNELS_2) {
					channel = (channel+1)%(CHANNELS_1+CHANNELS_2+1);
				} else {
					channel = 0x00;
				}
				printf("selecting channel ch %u %u (%u)\n",(channel/CHANNELS_1)+1,(channel%CHANNELS_1)+1,brightness[mode][channel]);
				break;
			case CHANNEL_PREVIOUS:
				if (0==channel) {
					channel = CHANNELS_1+CHANNELS_2;
				} else {
					channel--;
				}
				printf("selecting channel ch %u %u (%u)\n",(channel/CHANNELS_1)+1,(channel%CHANNELS_1)+1,brightness[mode][channel]);
				break;
			default:
				printf("unhandled IR action: %u\n", ir_code);
				break;
		}
	} else {
		puts("unknown IR command");
	}
}