119 lines
2.6 KiB
C
119 lines
2.6 KiB
C
#include <avr/io.h>
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#include <util/delay.h>
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#include "battery.h"
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/*
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* Battery
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*/
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void battery_init(void)
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{
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// blink
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battery_led(LED_ON); _delay_ms(500);
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battery_led(LED_OFF); _delay_ms(500);
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battery_led(LED_ON); _delay_ms(500);
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battery_led(LED_OFF); _delay_ms(500);
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// LED indicates charger status
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battery_led(LED_CHARGER);
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// ADC setting for voltage monitor
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// Ref:2.56V band-gap, Input:ADC0(PF0), Prescale:128(16MHz/128=125KHz)
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ADMUX = (1<<REFS1) | (1<<REFS0);
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ADCSRA = (1<<ADPS2) | (1<<ADPS1) | (1<<ADPS0);
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ADCSRA |= (1<<ADEN);
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}
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// Indicator for battery
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void battery_led(battery_led_t val)
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{
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if (val == LED_TOGGLE) {
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// Toggle LED
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DDRF |= (1<<5);
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PINF |= (1<<5);
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} else if (val == LED_ON) {
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// On overriding charger status
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DDRF |= (1<<5);
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PORTF &= ~(1<<5);
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} else if (val == LED_OFF) {
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// Off overriding charger status
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DDRF |= (1<<5);
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PORTF |= (1<<5);
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} else {
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// Display charger status
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DDRF &= ~(1<<5);
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PORTF &= ~(1<<5);
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}
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}
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bool battery_charging(void)
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{
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if (!(USBSTA&(1<<VBUS))) return false;
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// MCP73831:STAT
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// HiZ: Shutdown/No Battery
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// Low: Charging
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// Hi: Charged
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// preserve last register status
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uint8_t ddrf_prev = DDRF;
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uint8_t portf_prev = PORTF;
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// Input with pullup
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DDRF &= ~(1<<5);
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PORTF |= (1<<5);
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_delay_ms(1);
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bool charging = PINF&(1<<5) ? false : true;
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// restore last register status
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DDRF = (DDRF&~(1<<5)) | (ddrf_prev&(1<<5));
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PORTF = (PORTF&~(1<<5)) | (portf_prev&(1<<5));
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return charging;
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}
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// Returns voltage in mV
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uint16_t battery_voltage(void)
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{
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volatile uint16_t bat;
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//ADCSRA |= (1<<ADEN);
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// discard first result
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ADCSRA |= (1<<ADSC);
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while (ADCSRA & (1<<ADSC)) ;
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bat = ADC;
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// discard second result
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ADCSRA |= (1<<ADSC);
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while (ADCSRA & (1<<ADSC)) ;
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bat = ADC;
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ADCSRA |= (1<<ADSC);
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while (ADCSRA & (1<<ADSC)) ;
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bat = ADC;
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//ADCSRA &= ~(1<<ADEN);
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return (bat - BATTERY_ADC_OFFSET) * BATTERY_ADC_RESOLUTION;
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}
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static bool low_voltage(void) {
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static bool low = false;
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uint16_t v = battery_voltage();
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if (v < BATTERY_VOLTAGE_LOW_LIMIT) {
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low = true;
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} else if (v > BATTERY_VOLTAGE_LOW_RECOVERY) {
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low = false;
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}
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return low;
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}
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battery_status_t battery_status(void)
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{
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if (USBSTA&(1<<VBUS)) {
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/* powered */
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return battery_charging() ? CHARGING : FULL_CHARGED;
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} else {
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/* not powered */
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return low_voltage() ? LOW_VOLTAGE : DISCHARGING;
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}
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}
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