vbat.c File Reference

#include "avr_compiler.h"
#include "vbat.h"

Include dependency graph for vbat.c:

Go to the source code of this file.

Functions
void	vbat_enable_xosc (bool use1khz)
	This function starts the crystal oscillator with 1 or 1024 Hz clock output.
void	vbat_reset (void)
	This function resets the battery backup module.
uint8_t	vbat_system_check (bool first_time_startup)
	Check battery backup system status.

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Function Documentation

void vbat_enable_xosc

(

bool

use1khz

)

This function starts the crystal oscillator with 1 or 1024 Hz clock output.

Parameters:

use1khz

Boolean for selecting 1 kHz or 1 Hz RTC clock rate.

Definition at line 27 of file vbat.c.

Referenced by vbat_init().

{
        // Enable the failure detection.
        VBAT.CTRL |= VBAT_XOSCFDEN_bm;

        /* A delay is needed to give the voltage in the backup system some time
         * to stabilise.
         */
        delay_us(200);

        // Enable oscillator, with 1 kHz or 1 Hz output.
        if (use1khz)
                VBAT.CTRL |= VBAT_XOSCEN_bm | VBAT_XOSCSEL_bm;
        else
                VBAT.CTRL |= VBAT_XOSCEN_bm;
}

void vbat_reset

(

void

)

This function resets the battery backup module.

This function will set the access enable bit for the control register.

Definition at line 9 of file vbat.c.

References ENTER_CRITICAL_REGION, and LEAVE_CRITICAL_REGION.

Referenced by vbat_init().

{
        // Enable R/W access to the battery backup module.
        VBAT.CTRL = VBAT_ACCEN_bm;

        // Reset the module. (Reset bit is protected by CCP.)
        ENTER_CRITICAL_REGION();
        CCP = 0xD8;
        VBAT.CTRL = VBAT_RESET_bm;
        LEAVE_CRITICAL_REGION();
}

uint8_t vbat_system_check

(

bool

first_time_init

)

Check battery backup system status.

Parameters:

first_time_startup

When this is the first time the system starts then this is false otherwise true.

Returns:

Backup system status.

Definition at line 44 of file vbat.c.

References VBAT_STATUS_BBBOD, VBAT_STATUS_BBPOR, VBAT_STATUS_INIT, VBAT_STATUS_NO_POWER, VBAT_STATUS_OK, and VBAT_STATUS_XOSCFAIL.

Referenced by main().

{
        uint8_t vbat_status;
        /*
         * Check if sufficient power was detected on the VBAT input. The brown-
         * out detector (BBBOD) will be sampled once when the device starts up
         * and the result is visible as the BBPWR flag.
         */
        if (VBAT.STATUS & VBAT_BBPWR_bm)
                vbat_status = VBAT_STATUS_NO_POWER;
        else {
                /*
                 * We hav sufficient power, now we check if a power-on-reset
                 * (BBPOR) was detected on VBAT. This is visible from the BBPORF
                 * flag which is also only updated once when the device starts.
                 */
                if (VBAT.STATUS & VBAT_BBPORF_bm) {
                        if (first_time_startup)
                                vbat_status = VBAT_STATUS_INIT;
                        else
                                vbat_status = VBAT_STATUS_BBPOR;
                }
                else if (VBAT.STATUS & VBAT_BBBORF_bm)
                        vbat_status = VBAT_STATUS_BBBOD;
                else {
                        VBAT.CTRL = VBAT_ACCEN_bm;
                        if (VBAT.STATUS & VBAT_XOSCFAIL_bm)
                                vbat_status = VBAT_STATUS_XOSCFAIL;
                        else
                                vbat_status = VBAT_STATUS_OK;
                }
        }
        return vbat_status;
}