fern/sensor-watch
1
0
Fork 0
mirror of https://github.com/firewalkwithm3/Sensor-Watch.git synced 2024-11-22 19:20:30 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity

add method for detecting low battery

Browse source
This commit is contained in:
Joey Castillo 2021-08-31 18:47:35 -04:00
parent 36322fd737
commit b22915431b
3 changed files with 44 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

15
watch-library/watch/watch.c
View file

@ -35,3 +35,18 @@
#include "watch_uart.c"
#include "watch_deepsleep.c"
#include "watch_private.c"
bool battery_is_low = false;
// receives interrupts from MCLK, OSC32KCTRL, OSCCTRL, PAC, PM, SUPC and TAL, whatever that is.
void SYSTEM_Handler(void) {
if (SUPC->INTFLAG.bit.BOD33DET) {
battery_is_low = true;
SUPC->INTENCLR.bit.BOD33DET = 1;
SUPC->INTFLAG.reg &= ~SUPC_INTFLAG_BOD33DET;
}
}
bool watch_is_battery_low() {
return battery_is_low;
}

8
watch-library/watch/watch.h
View file

@ -65,4 +65,12 @@
#include "watch_private.h"
/** @brief Returns true when the battery voltage dips below 2.5V.
* @details A CR2016 battery will have a nominal voltage between 2.9 and 3 volts for most of its lifespan. Once the battery
* discharges to about 60%, the voltage will drift slightly lower; this may manifest as a dimmer LED. By the time
* the battery voltage has fallen to 2.5 volts, it will have probably less than 10% of its capacity remaining, and
* you can expect the voltage to drop relatively quickly as the battery dies.
*/
bool watch_is_battery_low();
#endif /* WATCH_H_ */

21
watch-library/watch/watch_private.c
View file

@ -32,6 +32,27 @@ void _watch_init() {
SUPC->VREG.bit.SEL = 1;
while(!SUPC->STATUS.bit.VREGRDY);
// set up the brownout detector (low battery warning)
NVIC_DisableIRQ(SYSTEM_IRQn);
NVIC_ClearPendingIRQ(SYSTEM_IRQn);
NVIC_EnableIRQ(SYSTEM_IRQn);
SUPC->BOD33.bit.ENABLE = 0; // BOD33 must be disabled to change its configuration
SUPC->BOD33.bit.VMON = 0; // Monitor VDD in active and standby mode
SUPC->BOD33.bit.ACTCFG = 1; // Enable sampling mode when active
SUPC->BOD33.bit.RUNSTDBY = 1; // Enable sampling mode in standby
SUPC->BOD33.bit.STDBYCFG = 1; // Run in standby
SUPC->BOD33.bit.RUNBKUP = 1; // Also run in backup mode
SUPC->BOD33.bit.PSEL = 0xB; // Check battery level every 4 seconds
SUPC->BOD33.bit.LEVEL = 31; // Detect brownout at 2.5V (1.445V + level * 34mV)
SUPC->BOD33.bit.BKUPLEVEL = 31; // Detect same level in backup mode
SUPC->BOD33.bit.ACTION = 0x2; // Generate an interrupt when BOD33 is triggered
SUPC->BOD33.bit.HYST = 0; // Disable hysteresis
while(!SUPC->STATUS.bit.B33SRDY);
// Enable interrupt on BOD33 detect
SUPC->INTENSET.bit.BOD33DET = 1;
SUPC->BOD33.bit.ENABLE = 1;
// External wake depends on RTC; calendar is a required module.
CALENDAR_0_init();
calendar_enable(&CALENDAR_0);