Using the WDT to wakeup from sleep

Created Mon, 16 Dec 2013 02:47:08 +0000 by SickBeard

SickBeard

Mon, 16 Dec 2013 02:47:08 +0000

So I've been trying to set up my fubarino SD to sleep then wake up after the WDT timeouts (it blinks the LED otherwise). I can get it to sleep, or I get it to blink, however not at the interval it should be blinking it (1sec off, 1sec on). I've tried changing the postscaler, and it seems not to make a difference.

majenko

Mon, 16 Dec 2013 08:55:34 +0000

Any chance of sharing your code with us?

SickBeard

Mon, 16 Dec 2013 14:23:46 +0000

Excuse the messiness; I've been trying out a lot, and don't know if it's necessary so I've kept it, but commented out. Please tell me if I'm doing something stupidly wrong, I really can't wrap my head around this.

void setup() {              
  WDTCONSET = 0x30; // post scaler
  WDTCONCLR = 0x0002;
  WDTCONSET = 0x8000;
  WDTCONSET = 0x01;
 // FWDTPS = 0b01100;
  // initialize the digital pin as an output.
  // Pin PIN_LED1 has an LED connected on most Arduino and compatible boards:
  pinMode(PIN_LED1, OUTPUT);     
  //DEVCFG1 = (1 << 23); //wdt enabled
 

  if (RCON & 0x18){
      asm volatile("eret");
  }
/*
  if (RCON & 0x14) {
   asm volatile ("eret");  
  }  

  if (RCON & 0x10){
  }*/
}

void loop() {
 /*SYSKEY = 0x12345678;
  SYSKEY = 0xAA996655;
  SYSKEY = 0x556699AA; //unlocked
  
  */OSCCONSET = 0x10;
  /*
  SYSKEY = 0x33333333;
*/   
    

  while (1) {
   
    
    digitalWrite(PIN_LED1, HIGH);   // set the LED on
    delay(5000);              // wait for a second
    digitalWrite(PIN_LED1, LOW);    // set the LED off
    delay(1000);          // wait for a second
    
    digitalWrite(PIN_LED1, HIGH);   // set the LED on
    delay(1000);              // wait for a second
    
    digitalWrite(PIN_LED1, LOW);    // set the LED off
    delay(1000);              // wait for a second
     asm("wait");
  }
}
//__ADC1Interrupt:

//asm("eret");

SickBeard

Wed, 18 Dec 2013 21:07:57 +0000

Any ideas, anyone?

jvvood

Thu, 19 Dec 2013 18:37:41 +0000

Any ideas, anyone?

In my Forth system using the following code:

//*  
//* sleep ( f --- )
//*    Put MCU to sleep mode.
//*    Switch off the USB module
//*    If f is true then turn on the WDT before going to sleep.
//*    Tested only with WDT reset. Need to test other wakeup sources !
void sleep(void) {
  UINT wdt = POP;
  SYSKEY = 0x0;
  SYSKEY = 0xAA996655;
  SYSKEY = 0x556699AA;
  OSCCONSET = 0x10; // set Power-Saving mode to Sleep
  SYSKEY = 0x0;
  if (wdt) {
    ClearWDT();
    EnableWDT();
    ClearWDT();
  }
  U1PWRC = 0;  // Switch off the USB module to save more power.
// put device in selected power-saving mode
  asm volatile( "wait" );
}

An example using sleep in Forth on a DP32 board:

hex

: .reset
    cr cr cr
    rcon@ ." RCON: " u. cr cr
    ." Cause of reset:" cr
    rcon@ 1 and if
        ." POR reset" cr
    then
    rcon@ 2 and if
        ." BOR reset" cr
    then
    rcon@ 4 and if
        ." IDLE reset" cr
    then
    rcon@ 8 and if
        ." SLEEP reset" cr
    then
    rcon@ 10 and if
        ." WDTO reset" cr
    then
    rcon@ 40 and if
        ." SWR reset" cr
    then
    rcon@ 80 and if
        ." EXT reset" cr
    then
;

decimal

11 constant LED

: main
  \ Set LED to output
   1 LED pm  

  \ blink LED 50 times
  \ this is the time to reconnect with terminal
  50 0 do
    LED d@ 0= LED d!
    100 delayms
  loop
  
  \ print cause of reset
  .reset
  
  \ wait for keypress in next 5 seconds
  cr ." Press any key to sleep or BootLoader button to abort !" cr
  25 0 do
    200 delayms
    LED d@ 0= LED d!
    ?key if
        leave
    then
  loop
  
  \ Switch off LED
  0 11 d!
  
  \ Switch on WDT and put MCU to sleep
  1 sleep
;


\ Start "main" automatically after reset.
\   Work all reset cause except External Reset (eg. Reset Button)
: autorun main ;

\ Save the current system to flash.
syssave

\ Execute a soft reset
0 reset

And the result in the terminal:

RCON: 10

Cause of reset:
WDTO reset

Press any key to sleep or BootLoader button to abort !