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fw: Implement better battery voltage monitoring

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This commit is contained in:
Markus Koch 2020-07-30 21:40:57 +02:00
parent e26471381a
commit ba069861ff
2 changed files with 34 additions and 3 deletions
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33
firmware/batmon.c
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@ -1,11 +1,18 @@
#include <avr/io.h> #include <avr/io.h>
#include "batmon.h" #include "batmon.h"
#include "systick.h"
static uint8_t vbat = 0;
void batmon_init() void batmon_init()
{ {
TCCR0A = 0;
TCCR0B = (1 << CS02);
TIMSK0 = (1 << TOIE0);
ADCSRA = (1 << ADPS2) | (1 << ADPS1); // 125 kHz ADC clock ADCSRA = (1 << ADPS2) | (1 << ADPS1); // 125 kHz ADC clock
ADMUX = ADC_CHANNEL | (1 << REFS0) | (1 << REFS1) | (1 << ADLAR); // Internal 1.2V bandgap, left adj. ADMUX = ADC_CHANNEL | (1 << REFS0) | (1 << REFS1) | (1 << ADLAR); // Internal 1.2V bandgap, left adj.
ADCSRB = 0; // Manual start ADCSRB = 0;
#if ADC_CHANNEL < 7 #if ADC_CHANNEL < 7
DIDR0 = (1 << ADC_CHANNEL); // Disconnect digital channel DIDR0 = (1 << ADC_CHANNEL); // Disconnect digital channel
#endif #endif
@ -16,10 +23,30 @@ void batmon_init()
// Enable ADC // Enable ADC
ADCSRA |= (1 << ADEN); ADCSRA |= (1 << ADEN);
ADCSRA |= (1 << ADSC);
}
uint8_t batmon_proc()
{
static uint16_t sum = 0;
static uint8_t cnt = 0;
if (ADCSRA & (1 << ADIF)) {
sum += ADCH;
if (!(cnt++)) {
vbat = sum >> 8;
sum = 0;
}
vbat = ADCH;
ADCSRA &= ~(1 << ADIF);
ADCSRA |= (1 << ADSC); // TODO: I want this to work off TIMER0
if (vbat < BAT_THRES_POWER_OFF)
return 1;
}
return 0;
} }
inline uint8_t batmon_get_voltage() inline uint8_t batmon_get_voltage()
{ {
ADCSRA |= (1 << ADSC); // TODO: Check whether this increases the power consumption of the chip by much return vbat;
return ADCH;
} }

4
firmware/batmon.h
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@ -6,7 +6,11 @@
#define PORT_ADCC(t) t##D #define PORT_ADCC(t) t##D
#define PIN_ADCC (1 << 1) #define PIN_ADCC (1 << 1)
#define BAT_THRES_POWER_ON 60 // TODO: Minimum ADC value to allow turning the device on
#define BAT_THRES_POWER_OFF 50 // TODO: ADC value to (hard) power off the device.
void batmon_init(); void batmon_init();
uint8_t batmon_get_voltage(); uint8_t batmon_get_voltage();
uint8_t batmon_proc();
#endif // BATMON_H #endif // BATMON_H