Since our production circuit board has been professionally produced, there is not room for an extra Xtal and caps to drive TMR1 so I am trying to get the WDT to do the wake from sleep but with only partial success. In particular it doesnt seem to matter what I put as a postscaler value the WDT seems to cycle at a fixed period of around 578 mSec (suspiciously similar to Nap 5 frequency!). I am setting CONFIG2H by using this instead of the corresponding (commented out) line in 18F4550.INC:
and then:Code:asm __CONFIG _CONFIG2H, _WDT_OFF_2H & _WDTPS_256_2H ;must comment out in 18F4550.INC, or change there, else duplicate error endasm
and i increments 128 in 74 secs (period = 578mSec), but different values of _WDTPS_1024_2H etc. make no difference. What am I missing here? It makes no difference whether I make the CPU sleep or idle (except to the current consumption 3 or 15 mA - most of the 3 lost in the 9v voltage regulator).Code:i = 0 lowpower: lcdout $FE, $02, "WDT ", hex2 i, i = i + 1 ' Do all the other stuff here (read ADC, store to Mem) clearwdt WDTCON = 1 'SWDTEN ' OSCCON.7 = 0 'Clear IDLEN - switch to SLEEP OSCCON.7 = 1 'Set IDLEN - switch to SEC_IDLE @ SLEEP @ NOP WDTCON = 0 ' WDT off goto lowpower
DEFINE NO_CLRWDT 1 makes no difference and the CLEARWDT also seems to make no difference!
I would like to have the ability to control the frequency as expected and am thinking I can sleep for most of the 1 second I want and fine tune with another timer while awake - PAUSE would be the simplest. Any ideas gratefully received!
Peter
PS It just occurs to me that I am using a Bootloader - could this mean that the Postscaler is set by the bootloader and not changed by my program - if so can I do anything to change this ??edit the bootloader somehow.
Originally Posted by Bruce
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