Hi,
You really need to show the program code you have already done, or at least let us know what language you are using.
You have various options for reading the switch, you can do it direct from within your main program loop or via PortB which has two types of Interrupt.
As you are just beginning I would think avoiding the interrupts will be the easier route for now.
Connect your switch with one end connected to 0v and the other to an input pin with a 10k pull up resistor.
Read its status regularly from within your main program loop, when it detects a change then thats your signal to go to the subroutine for the pedestians
Hi
Here is the program so far I have.
LIST p=16F88
#include "P16F88.INC"
CBLOCK 0x10 ; Temporary storage
state
l1,l2
ENDC
org 0 ; Start up vector.
goto setports ; Go to start up code.
org 4 ; Interrupt vector.
halt goto halt ; Sit in endless loop and do nothing.
setports clrw ; Zero in to W.
movwf PORTA ; Ensure PORTA is zero before we enable it.
movwf PORTB ; Ensure PORTB is zero before we enable it.
bsf STATUS,RP0 ; Select Bank 1
clrw ; Mask for all bits as outputs.
movwf TRISB ; Set TRISB register.
bcf STATUS,RP0 ; Reselect Bank 0.
initialise clrw ; Initial state.
movwf state ; Set it.
loop call getmask ; Convert state to bitmask.
movwf PORTB ; Write it to port.
incf state,W ; Increment state in to W.
andlw 0x03 ; Wrap it around.
movwf state ; Put it back in to memory.
call wait ; Wait
goto loop ; And loop
; Function to return bitmask for output port for current state.
; The top nibble contains the bits for one set of lights and the
; lower nibble the bits for the other set. Bit 1 is red, 2 is amber
; and bit three is green. Bit four is not used.
getmask movf state,W ; Get state in to W.
addwf PCL,F ; Add offset in W to PCL to calc. goto.
retlw 0x41 ; state==0 is Green and Red.
retlw 0x23 ; state==1 is Amber and Red/Amber
retlw 0x14 ; state==3 is Red and Green
retlw 0x32 ; state==4 is Red/Amber and Amber.
; Function using two loops to achieve a delay.
wait movlw 5
movwf l1
w1 call wait2
decfsz l1
goto w1
return
wait2 clrf l2
w2 decfsz l2
goto w2
return
END