~toykeeper/flashlight-firmware/trunk

/* STAR_off_time version 1.2
 *
 * Changelog
 *
 * 1.0 Initial version
 * 1.1 Bug fix
 * 1.2 Added support for dual PWM outputs and selection of PWM mode per output level
 * 1.3 Added ability to have turbo ramp down gradually instead of step down
 *
 */

/*
 * NANJG 105C Diagram
 *           ---
 *         -|   |- VCC
 *  Star 4 -|   |- Voltage ADC
 *  Star 3 -|   |- PWM
 *     GND -|   |- Star 2
 *           ---
 *
 * FUSES
 *		I use these fuse settings
 *		Low:  0x75	(4.8MHz CPU without 8x divider, 9.4kHz phase-correct PWM or 18.75kHz fast-PWM)
 *		High: 0xff
 *
 *      For more details on these settings, visit http://github.com/JCapSolutions/blf-firmware/wiki/PWM-Frequency
 *
 * STARS
 *		Star 2 = Moon if connected and alternate PWM output not used
 *		Star 3 = H-L if connected, L-H if not
 *		Star 4 = Capacitor for off-time
 *
 * VOLTAGE
 *		Resistor values for voltage divider (reference BLF-VLD README for more info)
 *		Reference voltage can be anywhere from 1.0 to 1.2, so this cannot be all that accurate
 *
 *           VCC
 *            |
 *           Vd (~.25 v drop from protection diode)
 *            |
 *          1912 (R1 19,100 ohms)
 *            |
 *            |---- PB2 from MCU
 *            |
 *          4701 (R2 4,700 ohms)
 *            |
 *           GND
 *
 *		ADC = ((V_bat - V_diode) * R2   * 255) / ((R1    + R2  ) * V_ref)
 *		125 = ((3.0   - .25    ) * 4700 * 255) / ((19100 + 4700) * 1.1  )
 *		121 = ((2.9   - .25    ) * 4700 * 255) / ((19100 + 4700) * 1.1  )
 *
 *		Well 125 and 121 were too close, so it shut off right after lowering to low mode, so I went with
 *		130 and 120
 *
 *		To find out what value to use, plug in the target voltage (V) to this equation
 *			value = (V * 4700 * 255) / (23800 * 1.1)
 *      
 */
#define F_CPU 4800000UL

/*
 * =========================================================================
 * Settings to modify per driver
 */

#define VOLTAGE_MON			// Comment out to disable

#define MEMORY				// Comment out to disable

//#define TICKS_250MS		// If enabled, ticks are every 250 ms. If disabled, ticks are every 500 ms
							// Affects turbo timeout/rampdown timing

#define MODE_MOON			3	// Can comment out to remove mode, but should be set through soldering stars
#define MODE_LOW			14  // Can comment out to remove mode
#define MODE_MED			39	// Can comment out to remove mode
//#define MODE_HIGH			255	// Can comment out to remove mode
#define MODE_TURBO			255	// Can comment out to remove mode
#define MODE_TURBO_LOW		140	// Level turbo ramps down to if turbo enabled
#define TURBO_TIMEOUT		240 // How many WTD ticks before before dropping down.  If ticks set for 500 ms, then 240 x .5 = 120 seconds.  Max value of 255 unless you change "ticks"
								// variable to uint8_t
//#define TURBO_RAMP_DOWN			// By default we will start to gradually ramp down, once TURBO_TIMEOUT ticks are reached, 1 PWM_LVL each tick until reaching MODE_TURBO_LOW PWM_LVL
								// If commented out, we will step down to MODE_TURBO_LOW once TURBO_TIMEOUT ticks are reached

#define FAST_PWM_START	    8 // Above what output level should we switch from phase correct to fast-PWM?
//#define DUAL_PWM_START		8 // Above what output level should we switch from the alternate PWM output to both PWM outputs?  Comment out to disable alternate PWM output

#define ADC_LOW				130	// When do we start ramping
#define ADC_CRIT			120 // When do we shut the light off

#define CAP_THRESHOLD		130  // Value between 1 and 255 corresponding with cap voltage (0 - 1.1v) where we consider it a short press to move to the next mode
								 // Not sure the lowest you can go before getting bad readings, but with a value of 70 and a 1uF cap, it seemed to switch sometimes
								 // even when waiting 10 seconds between presses.

/*
 * =========================================================================
 */

//#include <avr/pgmspace.h>
#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include <avr/wdt.h>	
#include <avr/eeprom.h>
#include <avr/sleep.h>
//#include <avr/power.h>

#define STAR2_PIN   PB0
#define STAR3_PIN   PB4
#define CAP_PIN     PB3
#define CAP_CHANNEL 0x03	// MUX 03 corresponds with PB3 (Star 4)
#define CAP_DIDR    ADC3D	// Digital input disable bit corresponding with PB3
#define PWM_PIN     PB1
#define VOLTAGE_PIN PB2
#define ADC_CHANNEL 0x01	// MUX 01 corresponds with PB2
#define ADC_DIDR 	ADC1D	// Digital input disable bit corresponding with PB2
#define ADC_PRSCL   0x06	// clk/64

#define PWM_LVL		OCR0B	// OCR0B is the output compare register for PB1
#define ALT_PWM_LVL OCR0A   // OCR0A is the output compare register for PB0

/*
 * global variables
 */

// Mode storage
uint8_t eepos = 0;
uint8_t eep[32];
uint8_t memory = 0;

// Modes (gets set when the light starts up based on stars)
static uint8_t modes[10];  // Don't need 10, but keeping it high enough to handle all
volatile uint8_t mode_idx = 0;
int     mode_dir = 0; // 1 or -1. Determined when checking stars. Do we increase or decrease the idx when moving up to a higher mode.
uint8_t mode_cnt = 0;

uint8_t lowbatt_cnt = 0;

void store_mode_idx(uint8_t lvl) {  //central method for writing (with wear leveling)
	uint8_t oldpos=eepos;
	eepos=(eepos+1)&31;  //wear leveling, use next cell
	// Write the current mode
	EEARL=eepos;  EEDR=lvl; EECR=32+4; EECR=32+4+2;  //WRITE  //32:write only (no erase)  4:enable  2:go
	while(EECR & 2); //wait for completion
	// Erase the last mode
	EEARL=oldpos;           EECR=16+4; EECR=16+4+2;  //ERASE  //16:erase only (no write)  4:enable  2:go
}
inline void read_mode_idx() {
	eeprom_read_block(&eep, 0, 32);
	while((eep[eepos] == 0xff) && (eepos < 32)) eepos++;
	if (eepos < 32) mode_idx = eep[eepos];//&0x10; What the?
	else eepos=0;
}

inline void next_mode() {
	if (mode_idx == 0 && mode_dir == -1) {
		// Wrap around
		mode_idx = mode_cnt - 1;
	} else {
		mode_idx += mode_dir;
		if (mode_idx > (mode_cnt - 1)) {
			// Wrap around
			mode_idx = 0;
		}
	}
}

inline void check_stars() {
	// Load up the modes based on stars
	// Always load up the modes array in order of lowest to highest mode
	// 0 being low for soldered, 1 for pulled-up for not soldered
	// Moon
#ifdef MODE_MOON
#ifndef DUAL_PWM_START
	if ((PINB & (1 << STAR2_PIN)) == 0) {
#endif
		modes[mode_cnt++] = MODE_MOON;
#ifndef DUAL_PWM_START
	}
#endif
#endif
#ifdef MODE_LOW
	modes[mode_cnt++] = MODE_LOW;
#endif
#ifdef MODE_MED
	modes[mode_cnt++] = MODE_MED;
#endif
#ifdef MODE_HIGH
	modes[mode_cnt++] = MODE_HIGH;
#endif
#ifdef MODE_TURBO
	modes[mode_cnt++] = MODE_TURBO;
#endif
	if ((PINB & (1 << STAR3_PIN)) == 0) {
		// High to Low
		mode_dir = -1;
	} else {
		mode_dir = 1;
	}
}

inline void WDT_on() {
	// Setup watchdog timer to only interrupt, not reset
	cli();							// Disable interrupts
	wdt_reset();					// Reset the WDT
	WDTCR |= (1<<WDCE) | (1<<WDE);  // Start timed sequence
	#ifdef TICKS_250MS
	WDTCR = (1<<WDTIE) | (1<<WDP2); // Enable interrupt every 250ms
	#else
	WDTCR = (1<<WDTIE) | (1<<WDP2) | (1<<WDP0); // Enable interrupt every 500ms
	#endif
	sei();							// Enable interrupts
}

inline void WDT_off()
{
	cli();							// Disable interrupts
	wdt_reset();					// Reset the WDT
	MCUSR &= ~(1<<WDRF);			// Clear Watchdog reset flag
	WDTCR |= (1<<WDCE) | (1<<WDE);  // Start timed sequence
	WDTCR = 0x00;					// Disable WDT
	sei();							// Enable interrupts
}

inline void ADC_on() {
	DIDR0 |= (1 << ADC_DIDR);							// disable digital input on ADC pin to reduce power consumption
	ADMUX  = (1 << REFS0) | (1 << ADLAR) | ADC_CHANNEL; // 1.1v reference, left-adjust, ADC1/PB2
	ADCSRA = (1 << ADEN ) | (1 << ADSC ) | ADC_PRSCL;   // enable, start, prescale
}

inline void ADC_off() {
	ADCSRA &= ~(1<<7); //ADC off
}

void set_output(uint8_t pwm_lvl) {
	#ifdef DUAL_PWM_START
	if (pwm_lvl > DUAL_PWM_START) {
		// Using the normal output along with the alternate
		PWM_LVL = pwm_lvl;
	} else {
		PWM_LVL = 0;
	}
	#else
	PWM_LVL = pwm_lvl;
	#endif
	// Always set alternate PWM value even if not compiled for dual output as we will use this value
	// throughout the code when trying to see what the current output level is.  Setting this wont affect
	// the output when alternate output is disabled.
	ALT_PWM_LVL = pwm_lvl;
}

#ifdef VOLTAGE_MON
uint8_t low_voltage(uint8_t voltage_val) {
	// Start conversion
	ADCSRA |= (1 << ADSC);
	// Wait for completion
	while (ADCSRA & (1 << ADSC));
	// See if voltage is lower than what we were looking for
	if (ADCH < voltage_val) {
		// See if it's been low for a while
		if (++lowbatt_cnt > 8) {
			lowbatt_cnt = 0;
			return 1;
		}
	} else {
		lowbatt_cnt = 0;
	}
	return 0;
}
#endif

ISR(WDT_vect) {
	static uint8_t ticks = 0;
	if (ticks < 255) ticks++;
	// If you want more than 255 for longer turbo timeouts
	//static uint16_t ticks = 0;
	//if (ticks < 60000) ticks++;
	
#ifdef MODE_TURBO	
	//if (ticks == TURBO_TIMEOUT && modes[mode_idx] == MODE_TURBO) { // Doesn't make any sense why this doesn't work
	if (ticks >= TURBO_TIMEOUT && mode_idx == (mode_cnt - 1) && PWM_LVL > MODE_TURBO_LOW) {
		#ifdef TURBO_RAMP_DOWN
		set_output(PWM_LVL - 1);
		#else
		// Turbo mode is always at end
		set_output(MODE_TURBO_LOW);
		if (MODE_TURBO_LOW <= modes[mode_idx-1]) {
			// Dropped at or below the previous mode, so set it to the stored mode
			// Kept this as it was the same functionality as before.  For the TURBO_RAMP_DOWN feature
			// it doesn't do this logic because I don't know what makes the most sense
			store_mode_idx(--mode_idx);
		}
		#endif
	}
#endif

}

int main(void)
{	
	// All ports default to input, but turn pull-up resistors on for the stars (not the ADC input!  Made that mistake already)
	#ifdef DUAL_PWM_START
	PORTB = (1 << STAR3_PIN);
	#else
	PORTB = (1 << STAR2_PIN) | (1 << STAR3_PIN);
	#endif
	
	// Determine what mode we should fire up
	// Read the last mode that was saved
	read_mode_idx();
	
	check_stars(); // Moving down here as it might take a bit for the pull-up to turn on?
	
	// Start up ADC for capacitor pin
	DIDR0 |= (1 << CAP_DIDR);							// disable digital input on ADC pin to reduce power consumption
	ADMUX  = (1 << REFS0) | (1 << ADLAR) | CAP_CHANNEL; // 1.1v reference, left-adjust, ADC3/PB3
	ADCSRA = (1 << ADEN ) | (1 << ADSC ) | ADC_PRSCL;   // enable, start, prescale
	
	// Wait for completion
	while (ADCSRA & (1 << ADSC));
	// Start again as datasheet says first result is unreliable
	ADCSRA |= (1 << ADSC);
	// Wait for completion
	while (ADCSRA & (1 << ADSC));
	if (ADCH > CAP_THRESHOLD) {
		// Indicates they did a short press, go to the next mode
		next_mode(); // Will handle wrap arounds
		store_mode_idx(mode_idx);
	} else {
		// Didn't have a short press, keep the same mode
	#ifndef MEMORY
		// Reset to the first mode
		mode_idx = ((mode_dir == 1) ? 0 : (mode_cnt - 1));
		store_mode_idx(mode_idx);
	#endif
	}
	// Turn off ADC
	ADC_off();
	
	// Charge up the capacitor by setting CAP_PIN to output
	DDRB  |= (1 << CAP_PIN);	// Output
    PORTB |= (1 << CAP_PIN);	// High
	
    // Set PWM pin to output
    DDRB |= (1 << PWM_PIN);
	#ifdef DUAL_PWM_START
	DDRB |= (1 << STAR2_PIN);
	#endif

    // Set timer to do PWM for correct output pin and set prescaler timing
    TCCR0A = 0x23; // phase corrected PWM is 0x21 for PB1, fast-PWM is 0x23
    TCCR0B = 0x01; // pre-scaler for timer (1 => 1, 2 => 8, 3 => 64...)
	
	// Turn features on or off as needed
	#ifdef VOLTAGE_MON
	ADC_on();
	#else
	ADC_off();
	#endif
	ACSR   |=  (1<<7); //AC off
	
	// Enable sleep mode set to Idle that will be triggered by the sleep_mode() command.
	// Will allow us to go idle between WDT interrupts
	set_sleep_mode(SLEEP_MODE_IDLE);
	
	uint8_t prev_mode_idx = mode_idx;
	
	WDT_on();
	
	// Now just fire up the mode
    // Set timer to do PWM for correct output pin and set prescaler timing
	if (modes[mode_idx] > FAST_PWM_START) {
		#ifdef DUAL_PWM_START
		TCCR0A = 0b10100011; // fast-PWM both outputs
		#else
		TCCR0A = 0b00100011; // fast-PWM normal output
		#endif
	} else {
		#ifdef DUAL_PWM_START
		TCCR0A = 0b10100001; // phase corrected PWM both outputs
		#else
		TCCR0A = 0b00100001; // phase corrected PWM normal output
		#endif
	}
	TCCR0B = 0x01; // pre-scaler for timer (1 => 1, 2 => 8, 3 => 64...)
	
	set_output(modes[mode_idx]);
	
	uint8_t i = 0;
	uint8_t hold_pwm;
	while(1) {
	#ifdef VOLTAGE_MON
		if (low_voltage(ADC_LOW)) {
			// We need to go to a lower level
			if (mode_idx == 0 && ALT_PWM_LVL <= modes[mode_idx]) {
				// Can't go any lower than the lowest mode
				// Wait until we hit the critical level before flashing 10 times and turning off
				while (!low_voltage(ADC_CRIT));
				i = 0;
				while (i++<10) {
					set_output(0);
					_delay_ms(250);
					set_output(modes[0]);
					_delay_ms(500);
				}
				// Turn off the light
				set_output(0);
				// Disable WDT so it doesn't wake us up
				WDT_off();
				// Power down as many components as possible
				set_sleep_mode(SLEEP_MODE_PWR_DOWN);
				sleep_mode();
			} else {
				// Flash 3 times before lowering
				hold_pwm = ALT_PWM_LVL;
				i = 0;
				while (i++<3) {
					set_output(0);
					_delay_ms(250);
					set_output(hold_pwm);
					_delay_ms(500);
				}
				// Lower the mode by half, but don't go below lowest level
				if ((ALT_PWM_LVL >> 1) < modes[0]) {
					set_output(modes[0]);
					mode_idx = 0;
				} else {					
					set_output(ALT_PWM_LVL >> 1);
				}					
				// See if we should change the current mode level if we've gone under the current mode.
				if (ALT_PWM_LVL < modes[mode_idx]) {
					// Lower our recorded mode
					mode_idx--;
				}
			}
			// Wait 3 seconds before lowering the level again
			_delay_ms(3000);
		}
	#endif
		sleep_mode();
	}

    return 0; // Standard Return Code
}