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/*
* Battery management
*
* Copyright (c) 2018-2020 Michael Buesch <m@bues.ch>
*
* 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 2 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, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "compat.h"
#include "debug.h"
#include "battery.h"
#include "main.h"
#include "arithmetic.h"
#include "pwm.h"
#include "adc.h"
#include "watchdog.h"
#include "curve.h"
#include "curve_data_sp2batdrop.h"
#include "movingavg.h"
#define BAT_AVERAGE 3u
static struct {
DEFINE_MOVINGAVG(movingavg, BAT_AVERAGE);
uint16_t interval_ms;
uint16_t elapsed_ms;
uint16_t avg_mv;
uint16_t drop_mv;
bool voltage_critical;
} bat;
/* Battery voltages below this threshold are critical: */
#define BAT_CRITICAL_MIN_MV 3200u /* millivolts */
/* Hysteresis for leaving critical-min state. */
#define BAT_CRITICAL_HYST_MV 300u /* millivolts */
/* Battery voltages above this threshold are not plausible: */
#define BAT_PLAUS_MAX_MV 6500u /* millivolts */
/* The maximum allowed voltage drop from the drop model. */
#define BAT_DROP_MODEL_MAX_MV 400u /* millivolts */
/* Battery monitoring intervals (in seconds). */
#if 1
#define BAT_INT_ON 3 /* During PWM output on */
#define BAT_INT_OFF (60 * 2) /* During PWM output off (setpoint=0) */
#define BAT_INT_CRIT (60 * 3) /* During low battery */
#else
#define BAT_INT_ON 1
#define BAT_INT_OFF 1
#define BAT_INT_CRIT 1
#endif
/* Set the interval that the battery voltage should be measured in.
* Interrupts shall be disabled before calling this function. */
void set_battery_mon_interval(uint16_t seconds)
{
if (USE_BAT_MONITOR)
bat.interval_ms = lim_u16((uint32_t)seconds * 1000u);
}
/* Update the battery measurement interval based on the PWM setpoint.
* Interrupts shall be disabled before calling this function. */
void battery_update_setpoint(void)
{
uint8_t i;
bool any_sp_nonzero;
if (USE_BAT_MONITOR) {
/* Reconfigure the battery measurement interval. */
if (battery_voltage_is_critical()) {
set_battery_mon_interval(BAT_INT_CRIT);
} else {
any_sp_nonzero = false;
for (i = 0u; i < NR_PWM; i++)
any_sp_nonzero |= pwm_sp_get(IF_MULTIPWM(i)) > 0u;
if (any_sp_nonzero)
set_battery_mon_interval(BAT_INT_ON);
else
set_battery_mon_interval(BAT_INT_OFF);
}
}
}
/* Returns true, if the battery voltage reached a critical level. */
bool battery_voltage_is_critical(void)
{
return bat.voltage_critical && USE_BAT_MONITOR;
}
/* Evaluate the measured battery voltage.
* May be called with interrupts enabled. */
void evaluate_battery_voltage(uint16_t vcc_mv)
{
uint16_t setpoint;
uint16_t drop_mv;
uint16_t avg_vcc_mv;
uint16_t noload_vcc_mv;
uint8_t irq_state;
uint8_t i;
if (USE_BAT_MONITOR) {
/* Calculate moving average. */
avg_vcc_mv = movingavg_calc(&bat.movingavg, vcc_mv);
/* Get the active setpoint.
* If the battery voltage already is critical
* and PWM is turned off, then this will be 0.
* We add all PWM setpoints.
* That's not physically correct, but good enough for now. */
setpoint = 0u;
for (i = 0u; i < NR_PWM; i++)
setpoint = add_sat_u16(setpoint, pwm_sp_get(IF_MULTIPWM(i)));
/* Calculate the battery voltage that we would have without load.
* by adding the drop voltage from the drop model. */
drop_mv = curve_interpolate(sp2batdrop_curve,
ARRAY_SIZE(sp2batdrop_curve),
setpoint);
drop_mv = min(drop_mv, BAT_DROP_MODEL_MAX_MV);
noload_vcc_mv = add_sat_u16(avg_vcc_mv, drop_mv);
dprintf("Battery: vcc_mv=%u avg_vcc_mv=%u drop_mv=%u noload_vcc_mv=%u\r\n",
vcc_mv, avg_vcc_mv, drop_mv, noload_vcc_mv);
/* Evaluate the no-load battery voltage and set the
* critical flag, if needed. */
irq_state = irq_disable_save();
if (noload_vcc_mv >= (BAT_CRITICAL_MIN_MV + BAT_CRITICAL_HYST_MV)) {
if (bat.voltage_critical)
dprintf("Battery voltage not critical anymore.\r\n");
bat.voltage_critical = false;
}
if (noload_vcc_mv < BAT_CRITICAL_MIN_MV) {
if (!bat.voltage_critical)
dprintf("Battery voltage critical: Under-voltage.\r\n");
bat.voltage_critical = true;
}
if (noload_vcc_mv > BAT_PLAUS_MAX_MV) {
if (!bat.voltage_critical)
dprintf("Battery voltage critical: Over-voltage.\r\n");
bat.voltage_critical = true;
}
bat.avg_mv = avg_vcc_mv;
bat.drop_mv = drop_mv;
irq_restore(irq_state);
}
}
/* Get the current battery voltage.
* May be called with interrupts enabled. */
void battery_get_voltage(uint16_t *avg_mv, uint16_t *drop_mv)
{
uint8_t irq_state;
if (USE_BAT_MONITOR) {
irq_state = irq_disable_save();
*avg_mv = bat.avg_mv;
*drop_mv = bat.drop_mv;
irq_restore(irq_state);
} else
*avg_mv = *drop_mv = 0;
}
/* A watchdog interrupt just occurred. */
void battery_handle_watchdog_interrupt(void)
{
if (USE_BAT_MONITOR) {
/* Check if we need to measure the battery voltage. */
bat.elapsed_ms = add_sat_u16(bat.elapsed_ms, watchdog_interval_ms());
if (bat.elapsed_ms >= bat.interval_ms) {
bat.elapsed_ms = 0;
/* Must be called with interrupts disabled. */
adc_request_battery_measurement();
}
}
}
void battery_init(void)
{
if (USE_BAT_MONITOR) {
movingavg_init(&bat.movingavg, BAT_AVERAGE);
set_battery_mon_interval(0);
}
}
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