Reading if Pin is High or Low?

[Spindle]

Hey guys/gals.

I am working on a project that involved an SPDT switch. I have the middle of the switch wired to a 5volt source and the other two wired to PORTB.5 and PORTB.7. What I want to do is check if PORTB.B or PORTB.7 goes high so then I can tell my PIC to drive my motor. PORTB.5 will be to drive my motor forward and PORTB.7 is to drive my motor reverse. Is there something similar to.

if PORTB.5 = HIGH Then?

Thanks in advanced.

- Matthew

[Art]

yes, it's
IF portb.5 = 1 THEN 'check if portb.5 is high

Cheers, Art.

[mister_e]

1. Be sure you place a pull down resistor on both PORTB pins
2. Be sure your pin is define as input with the TRIS setting too

my 2 cents... as always

TRISB.5=1

IF PORTB.5 THEN ' do the same as IF PORTB.5=1 THEN
    ' do something here
    ENDIF

OR, if your PIC have some A/D built in, you can use one channel to read your switch and do all the according stuff on 1 pin. You just need few resistors.
something like this...
<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=385&stc=1">

once it's done you use a snip of code like this

ADCIN 0,ForwardReverse
IF ForwardReverse<110 then
    Gosub MotorReverse
    ENDIF

IF ForwardReverse>140 then
    Gosub MotorForward
    ENDIF

110 and 140 are arbitrary value. Could work as is, but test it before. Set up a 8 bit A/D conversion.

[Spindle]

hrmm, something isn't right...

[code]

CMCON = 7 ' Disable analog comparator
TRISA = %11110110 ' set PORTA to input
TRISB = %11110000 ' set PORTB to output
DEFINE HSER_BAUD 9600 'send serial data at 2400 baud

UP VAR PORTB.5
DOWN var PORTB.7
FM VAR PORTB.2

POSITION var word 'Position value
VELOCITY var word 'Average velocity value
FUNCTION var word 'Function register
I var byte 'Loop variable

TRISB.5 = 1
TRISB.7 = 1

MAIN:

if UP THen
serout FM, T9600 ,["W01 01 200", CR, LF] 'Write velocity limit value
serout FM,T9600,["P01 270000", CR, LF] 'Send MOVETO_ABSOLUTE command

for I = 1 to 100
pause 25
serout FM,T9600,["R01 00",CR,LF]
serout FM,T9600,["R01 14",CR,LF]
next
endif

if DOWN THEN
serout FM, T9600 ,["W01 01 200", CR, LF] 'Write velocity limit value
serout FM,T9600,["P01 0", CR, LF] 'Send MOVETO_ABSOLUTE command

for I = 1 to 100
pause 25
serout FM,T9600,["R01 00",CR,LF]
serout FM,T9600,["R01 14",CR,LF]
next
endif

goto MAIN

END

[code/]

I am trying to see which pin is high, RB7 or RB5 and then send the right command to the motor driving circuit. No movement however :\

[mister_e]

CMCON = 7         ' Disable analog comparator
TRISA = %11110110 ' set PORTA to input
TRISB = %11110000 ' set PORTB to output

UP   VAR PORTB.5
DOWN var PORTB.7
FM   VAR PORTB.2 

POSITION var word    'Position value 
VELOCITY var word    'Average velocity value 
FUNCTION var word    'Function register 
I        var byte    'Loop variable
T9600    con 2 ' <== Baudrate definition in case you don't use
               ' INCLUDE "modedefs.bas" line

MAIN:
    if UP THen
       serout FM, T9600 ,["W01 01 200", CR, LF] 'Write velocity limit value 
       serout FM,T9600,["P01 270000", CR, LF]   'Send MOVETO_ABSOLUTE command
    
       for I = 1 to 100
           pause 25
           serout FM,T9600,["R01 00",CR,LF]
           serout FM,T9600,["R01 14",CR,LF]
           next 
       endif
    
    if DOWN THEN
       serout FM, T9600 ,["W01 01 200", CR, LF] 'Write velocity limit value 
       serout FM,T9600,["P01 0", CR, LF]        'Send MOVETO_ABSOLUTE command
    
       for I = 1 to 100
           pause 25
           serout FM,T9600,["R01 00",CR,LF]
           serout FM,T9600,["R01 14",CR,LF]
           next 
       endif
    
    goto MAIN

The DEFINE HSER_BAUD 9600 'send serial data at 2400 baud have nothing to do with SEROUT, AND i don't see any crystal speed declaration. @9600 bauds with SEROUT, 8MHZ or higher is highely recommended.

[Spindle]

I am using a PIC16F628 if that helps. It still isn't working for some reason. When i flip the switch nothing happend, but then the motor starts turning in like 30-40 secs. Its weird hehe. Its also 3:40am and getting late. I'll look at it again with fresh eyes in the morning but any more help is still apreciated.