wdt problem from sleep

[Steveny]

Hi,

I'm using timer2 on a 16f628 to transmit data at a given rate for given time period. However I need the PIC to go to sleep in between data burst. Unfortunately i can't seem to wake the PIC up again using the WDT when its a sleep. It seems to work ok when I don't have it in sleep mode or use a wdt.

I've listed the basics of the programs below and how i set most the things up. I also make sure that I have restart the wdt before it times_out and resets.





Cut down version of program

#include "16F628.h"
#fuses XT,WDT,NOPROTECT
#use Delay (clock=4000000)

#int_timer2

/*interrupt handler */
handler() {
restart_wdt();
do other stuff...

}


void main(void) {

set_tris_a(0xFF) ; /*set all port a for input*/
set_tris_b(0x00) ; /*set all port b for output*/

setup_timer_2(T2_DIV_BY_1,128,2);
setup_wdt(WDT_18MS);

enable_interrupts(INT_TIMER2) ;
enable_interrupts(GLOBAL) ;


while(1) {

restart_wdt();
sleep();

do stuff.......using inturrupt handler for given
time period..when finished go back to sleep.

}
}


Any help much appreciated..


Steve
___________________________
This message was ported from CCS's old forum
Original Post ID: 8939

[Tomi]

Clock is off under sleep so Timer2 never incremented under sleep. Use Timer1 with external 32768 Hz xtal and use Timer1 interrupt for both wakeup and timing the transmit.

:=Hi,
:=
:=I'm using timer2 on a 16f628 to transmit data at a given rate for given time period. However I need the PIC to go to sleep in between data burst. Unfortunately i can't seem to wake the PIC up again using the WDT when its a sleep. It seems to work ok when I don't have it in sleep mode or use a wdt.
:=
:=I've listed the basics of the programs below and how i set most the things up. I also make sure that I have restart the wdt before it times_out and resets.
:=
:=
:=
:=
:=
:=Cut down version of program
:=
:=#include "16F628.h"
:=#fuses XT,WDT,NOPROTECT
:=#use Delay (clock=4000000)
:=
:=#int_timer2
:=
:=/*interrupt handler */
:=handler() {
:= restart_wdt();
:= do other stuff...
:=
:=}
:=
:=
:=void main(void) {
:=
:= set_tris_a(0xFF) ; /*set all port a for input*/
:= set_tris_b(0x00) ; /*set all port b for output*/
:=
:= setup_timer_2(T2_DIV_BY_1,128,2);
:= setup_wdt(WDT_18MS);
:=
:= enable_interrupts(INT_TIMER2) ;
:= enable_interrupts(GLOBAL) ;
:=
:=
:= while(1) {
:=
:= restart_wdt();
:= sleep();
:=
:= do stuff.......using inturrupt handler for given
:= time period..when finished go back to sleep.
:=
:= }
:=}
:=
:=
:=Any help much appreciated..
:=
:=
:=Steve
___________________________
This message was ported from CCS's old forum
Original Post ID: 8958

[Steveny]

I've fixed the problem now by using

setup_counters(RTCC_INTERNAL, WDT_2304MS);

the first timer0 as the wdt. However there is an error in the code below in which I forgot to put a delay instruction to allow the interrupt to happen a number of times before it went back to sleep. So the pic woke up checked somthing and went back to sleep before the interrupt had time to transmit data. DOH!!!







:=Clock is off under sleep so Timer2 never incremented under sleep. Use Timer1 with external 32768 Hz xtal and use Timer1 interrupt for both wakeup and timing the transmit.
:=
:=:=Hi,
:=:=
:=:=I'm using timer2 on a 16f628 to transmit data at a given rate for given time period. However I need the PIC to go to sleep in between data burst. Unfortunately i can't seem to wake the PIC up again using the WDT when its a sleep. It seems to work ok when I don't have it in sleep mode or use a wdt.
:=:=
:=:=I've listed the basics of the programs below and how i set most the things up. I also make sure that I have restart the wdt before it times_out and resets.
:=:=
:=:=
:=:=
:=:=
:=:=
:=:=Cut down version of program
:=:=
:=:=#include "16F628.h"
:=:=#fuses XT,WDT,NOPROTECT
:=:=#use Delay (clock=4000000)
:=:=
:=:=#int_timer2
:=:=
:=:=/*interrupt handler */
:=:=handler() {
:=:= restart_wdt();
:=:= do other stuff...
:=:=
:=:=}
:=:=
:=:=
:=:=void main(void) {
:=:=
:=:= set_tris_a(0xFF) ; /*set all port a for input*/
:=:= set_tris_b(0x00) ; /*set all port b for output*/
:=:=
:=:= setup_timer_2(T2_DIV_BY_1,128,2);
:=:= setup_wdt(WDT_18MS);
:=:=
:=:= enable_interrupts(INT_TIMER2) ;
:=:= enable_interrupts(GLOBAL) ;
:=:=
:=:=
:=:= while(1) {
:=:=
:=:= restart_wdt();
:=:= sleep();
:=:=
:=:= do stuff.......using inturrupt handler for given
:=:= time period..when finished go back to sleep.
:=:=
:=:= }
:=:=}
:=:=
:=:=
:=:=Any help much appreciated..
:=:=
:=:=
:=:=Steve
___________________________
This message was ported from CCS's old forum
Original Post ID: 8969