do I need an interrupt?

[Acetronics2]

Just drive pin 4 from the Mystery slave circuit ( 8 pins ooooooold timer , cmos version available, its generic number is 3 times 10 halves ... )

Alain

[mister_e]

OK, do a search for Timer interrupt first. in the interrupt routine you'll have to determine:
1. i'm i on the HIGH pulse?... since how may time? enough? if so do the low pulse
2. same as 1 for low pulse

try it. If there's any other problem, i see some method.

OR do a short pause loop, check the pin state in the loop.

[peterdeco1]

what I did was

START:
IF PORTB.0 = 0 THEN START

WORK:
DO SOMETHING HERE & THERE 'this takes 250ms to complete
LET X = X + 1
IF X > 333 THEN GOSUB GOHIGH
IF PORTB.0 = 0 THEN START
GOTO WORK

GOHIGH:
HIGH PORTC.3
PAUSE 500
LOW PORTC.3
LET X = 0
RETURN

So, after about 3 seconds my port goes high for 500ms but I still have a 500ms + 250ms = 750ms gap where my inputs are ignored. A 555 one-shot would work fine but I want to avoid adding more circuitry if possible.

[Acetronics2]

Hi,

As all your inputs are on PortB ... why not use the simple feature " interrupt on PortB change " ???

you just have to check which input caused the interrupt and do what needed ...

That would not disturb your PWM sections nor make great changes to your tempo's, even if a basic interrupt used.

( note it's an Excellent excercise for trying Darrel's Instant interrupts, too ... )

just change PAUSE 500 to

For i = 1 to 500
PAUSE 1
Next i

... as stated in the MANUAL, Basic interrupts section ....


Alain