131 lines
3.2 KiB
C
131 lines
3.2 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(100);
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battery_led(LED_OFF); _delay_ms(100);
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battery_led(LED_ON); _delay_ms(100);
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battery_led(LED_OFF); _delay_ms(100);
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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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// digital input buffer disable(24.9.5)
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DIDR0 = (1<<ADC0D) | (1<<ADC4D) | (1<<ADC7D);
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DIDR1 = (1<<AIN0D);
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DIDR2 = (1<<ADC8D) | (1<<ADC9D) | (1<<ADC11D) | (1<<ADC12D) | (1<<ADC13D);
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// ADC disable voltate divider(PF4)
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DDRF |= (1<<4);
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PORTF &= ~(1<<4);
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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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// Charger Status:
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// MCP73831 MCP73832 LTC4054 Status
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// Hi-Z Hi-Z Hi-Z Shutdown/No Battery
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// Low Low Low Charging
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// Hi Hi-Z Hi-Z 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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// TODO: With MCP73831 this can not get stable status when charging.
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// LED is powered from PSEL line(USB or Lipo)
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// due to weak low output of STAT pin?
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// due to pull-up'd via resitor and LED?
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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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// ADC disable voltate divider(PF4)
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DDRF |= (1<<4);
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PORTF |= (1<<4);
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volatile uint16_t bat;
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ADCSRA |= (1<<ADEN);
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_delay_ms(1); // wait for charging S/H capacitance
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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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// ADC disable voltate divider(PF4)
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DDRF |= (1<<4);
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PORTF &= ~(1<<4);
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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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