Help with Pic Delay Pulse code please

[Chris Barron]

I hope this explains it.

Any ideas,,

Cheers
Dave...

Yes I see what you need now.
I've approached this by starting a timer of 1 second (Delayticks = 100) every time the input is activated, by detecting the high to low transition of the input signal.

On a long (good) signal the timer will elapse after 1 second because there have been no other high to low transitions of the input signal
On a short droppy signal there are lots of high to low transitions, so the 1 second timer keeps being reset.

By buffering the states of pins this way you can isolate high-low and low-high transitions, as well as both-high and both-low conditions. The program doesn't 'stop' in any wait loops so you should be able to add more functions inline, there is just the 10mS pause holding things up every iteration.

It compiles alright. How does it work ?
Chris




'************************************************* ***************
'* Name : UNTITLED.BAS *
'* Author : Chris Barron *
'* Notice : Copyright (c) 2009 Chris Barron *
'* : All Rights Reserved *
'* Date : 01/04/2009 *
'* Version : 1.0 *
'* Notes : *
'* : *
'************************************************* ***************
'************************************************* * *************

'G7JIQ MICRO LINK REPEATER
'PIC 12F675
'Internal RC clock
'
' PIC Defines
' -----------
@ DEVICE pic12F675, INTRC_OSC_NOCLKOUT
' System Clock Options (Internal)
@ DEVICE pic12F675, WDT_ON
' Watchdog Timer
@ DEVICE pic12F675, PWRT_ON
' Power-On Timer
@ DEVICE pic12F675, MCLR_OFF
' Master Clear Options (Internal)
@ DEVICE pic12F675, BOD_ON
' Brown-Out Detect
@ DEVICE pic12F675, CPD_OFF
' Data Memory Code Protect
@ DEVICE pic12F675, PROTECT_OFF
' Program Code Protection

'
' Define Hardware
' ---------------
InputTrigger var GPIO.5 ' Input normally HIGH, goes LOW to Trigger
InputReset var GPIO.2 ' Input normally HIGH, goes LOW to RESET
OutputLine var GPIO.0 ' Normally HIGH, goes LOW when triggered
Led var GPIO.1

'
' Define Variables
' ----------------
DelayTick var Byte ' 100mS Tick Counter
myflags var byte
'
' Initialise PIC
' --------------
Reset:
TRISIO=%00100100 ' Preset I/O
CMCON=%00000111 ' Disable Comparators
ANSEL=%00000000 ' Disable ADC
DelayTick=100 ' Reset Counter
myflags = 0
high OutputLine ' Everything RESET



' Main Program Loop
' -----------------
Loop:
'
' Test for RESET
' --------------
While InputReset=0 ' Just wait here if RESET
high OutputLine ' Reset Output
myflags = 0
DelayTick = 100
Wend

' We're using the lower 2 bits of the 'myflags' register to store the state of
' the input pin over the last two program loop iterations
' myflags.0 stores the current pin state and myflags.1 stores the previous
'state.
myflags.1 = myflags.0 ' Move the last 'current state' into the 'last state' bit
myflags.0 = InputTrigger ' Store the current state

' By storing the two states we can detect the transition from high to low
' A high to low transition = 00000010 = decimal 2
' A low to high transition = 00000001 = decimal 1

if myflags = 2 then
DelayTick = 100 ' A high to low transition, reset the delay
else
if delaytick > 0 then delaytick = delaytick - 1
endif

pause 10 ' adjust to get the resolution required (10 x DelayTick = total hang time)

if inputtrigger = 0 then low OutputLine; if input is active set output active

if ((inputtrigger = 1) and (Delaytick = 0)) then high outputline

goto loop: