Hi all,
Was playing around with Nick Gammon's work on AVR sleep modes (Gammon Forum : Electronics : Microprocessors : Power saving techniques for microprocessors - Sketch I near the bottom of the page). I wanted to have a Serial.print statement while the processor is awake, but I think I'm missing something. The serial monitor has gibberish, and I can't figure out why.
Here's the code. Runs on a standard UNO (IDE 1.6.4):
#include <avr/sleep.h>
#include <avr/wdt.h>
#include <avr/power.h>
const byte LED = 13;
void setup () {
pinMode (LED, OUTPUT);
}
void loop ()
{
digitalWrite (LED, HIGH);
delay (50);
Serial.begin(9600);
Serial.println("test");
Serial.end();
digitalWrite (LED, LOW);
//pinMode (LED, INPUT);
// disable ADC
ADCSRA = 0;
// clear various "reset" flags
MCUSR = 0;
// allow changes, disable reset
WDTCSR = bit (WDCE) | bit (WDE);
// set interrupt mode and an interval
WDTCSR = bit (WDIE) | bit (WDP1) | bit (WDP2); // set WDIE, and 1 second delay
wdt_reset(); // pat the dog
set_sleep_mode (SLEEP_MODE_STANDBY);
noInterrupts (); // timed sequence follows
sleep_enable();
// turn off brown-out enable in software
MCUCR = bit (BODS) | bit (BODSE);
MCUCR = bit (BODS);
interrupts (); // guarantees next instruction executed
sleep_cpu ();
// cancel sleep as a precaution
sleep_disable();
} // end of loop
// watchdog interrupt
ISR (WDT_vect)
{
wdt_disable(); // disable watchdog
} // end of WDT_vect
I have attached the serial output (sorry, couldn't figure out how to simply copy/paste).
The first one (test Catest Catest...) is with the Serial.end() statement included.
The second one (WON5) is with the Serial.end() statement commented out.
Many thanks.
