POWER

This module contains low level functions for power configuration. More...

Files
file	stm32f103cb_power.h
	Header file for stm32f103cb Power.

Functions
void	POWER_reset (void)
	Resets the system.
void	POWER_sleep (void)
	Put the system in sleep mode. More...
void	POWER_noSleep (void)
	Disable sleep mode. More...
void	POWER_standby (void)
	Put the device into standby mode. More...
uint8_t	POWER_fromStandby (void)
	Check if the system is restarting from standby mode. More...
void	POWER_stop (void)
	Put the device into stop mode. More...
uint8_t	POWER_fromStop (void)
	Check if MCU was in stop mode and reset flags. More...

Detailed Description

This module contains low level functions for power configuration.

There are four power modes that the MCU can operate in. Each proceeding mode has a lower power consumption but higher restart time.

• Normal, This is the default state, every works as usual
• Sleep, The clock is stalled, all NVIC functions remain, pin setings held in current state any ISR routine will fire and execute, RAM contents preserved. This mode can be disabled by using POWER_noSleep() in any ISR.
• Stop, The clock is stalled, all perihperal clock stopped (not RTC). Only EXTI (external pin) interrupts enabled. RAM contents preserved, program counter preserved. When this mode is exited all peripherals need to be set up again.
• Standby, All clocks and perihperals stopped, external pins set as floating, RAM contents lost, program counter lost. System can only be woken by RTC alarm or rising edge on PA1. On wakeup the system is as from reset state.

This module also contains the hard fault handler. In its implementation, the handler determines if the bootloader is being used (Data register 1 of the backup domain = 1) and resets to boot mode.

If the bootloader is not being used, the system simply stalls.

Author

Stuart Ianna

Version

1.0

Date

July 2018

Copyright

GNU GPLv3

Warning

None

Bug:

Todo:

Compilers

• arm-none-eabi-gcc (15:4.9.3+svn231177-1) 4.9.3 20150529 (prerelease)

Example Usage

This program works over USART_1. It provides four options which can be selected through terminal.

• 1 But the system in sleep mode, wake up in 3 seconds using systick ISR
• 2 Put the system in stop mode, wake up with rising edge on PA0
• 3 Put the system in standby mode, wake up in 3 seconds using RTC alarm
• 4 Reset the sytem.

#include <stm32f103cb_core.h>
#include <coms128.h>

void data(uint8_t byte);
volatile uint8_t flag;
void callback(void);
void rising(void);
void systemInit(void);

int main(void){

    systemInit();

    //RTC runs in stop mode
    //It only gets set up once
    RTC_setup(100);
    RTC_calibrate(100);

    //Display method of reset
    if(POWER_fromStandby()){

        printl("Standby reset");

    }
    else{

        printl("Soft reset");
    }

    while(1){

        switch(flag){

            case 1:

                flag = 0;
                printl("Sleeping, wake on systick ISR");
                delayms(100);           //Delay for message to print.
                SYSTICK_setup(3000000,&callback);   //3 seconds
                POWER_sleep();
                printl("Woke from sleep");
                break;

            case 2:

                flag = 0;
                printl("Stoping, wake on EXTI ISR");
                delayms(100);           //Delay for message to print.
                RTC_enableAlarmISR(RTC_getCount() + 30,NULL);
                POWER_stop();
                printl("Woke from stop");
                break;
            case 3:

                flag = 0;
                printl("Standby, wake after 3 seconds");
                delayms(100);           //Delay for message to print.

                //Standby wakes from RTC alarm
                RTC_enableAlarmISR(RTC_getCount() + 30,NULL); 
                POWER_standby();
                break;
            default:
                //Do nothing
                break;
        }
    }
}

//Chosse which power mode to use

// 1 = Sleep
// 2 = Stop
// 3 = Standby
// 4 = Reset
void data(uint8_t byte){

    switch(byte){

        case '1':

            flag = 1;
            break;
        case '2':

            flag = 2;
            break;
        case '3':

            flag = 3;
            break;
        case '4':

            POWER_reset();
            break;
        default:

            //Echo characters
            print((char)byte);
            break;
    }

}

//Systick callback to wake from sleep mode
void callback(void){

    //Disable sleep mode
    //If not disabled sleep mode begins again after ISR
    POWER_noSleep();

    //Stop the timer
    SYSTICK_stop();
}

//Rising edge on port A pin 0
void rising(void){

    if(POWER_fromStop()){

        systemInit();
    }
}

void systemInit(void){

    USART_setup(USART_1);
    USART_setBaud(USART_1,USART_BAUD_115200);
    USART_setRxISR(USART_1,&data);
    COMS(USART_1);
    GPIO_ISREnable(PORTA,PIN0,GPIO_RISING,&rising);
}

Function Documentation

uint8_t POWER_fromStandby

(

void

)

Check if the system is restarting from standby mode.

This should always be used if standby mode is used. This resets the standby wake flags. mode.

Definition at line 99 of file stm32f103cb_power.c.

uint8_t POWER_fromStop

(

void

)

Check if MCU was in stop mode and reset flags.

This should always be used if stop mode is used.

Definition at line 84 of file stm32f103cb_power.c.

void POWER_noSleep

(

void

)

Disable sleep mode.

This should be called inside an ISR.

Definition at line 59 of file stm32f103cb_power.c.

void POWER_sleep

(

void

)

Put the system in sleep mode.

ISR are still enabled. This mode can be exited by calling Power_noSleep() inside an ISR.

Definition at line 53 of file stm32f103cb_power.c.

void POWER_standby

(

void

)

Put the device into standby mode.

The RTC must be enabled with an alarm event to exit from standby mode.

Definition at line 65 of file stm32f103cb_power.c.

void POWER_stop

(

void

)

Put the device into stop mode.

The device needs to be woken with an EXTI interrupt or RTC alarm event. All clocks need to be reinitialized after stop mode.

Definition at line 75 of file stm32f103cb_power.c.