Post by thread:first program

I got my programmer going today and I am trying to assemble a program. A switch on port A is ment to turn a LED on/off on port B. loop BFTSC porta,0 ;if bit 0 porta is set then BSF portb,0 ;turn on bit 0 port b else BCF portb,0 ;turn of bit 0 port b goto loop I am using Charles Mannings development system. (same as the Kits R Us kit, I think) Below is the error message I get. Can anyone give me a few tips? Thanks. -----------------------------------error message-------------------------- C:\Seth\PIC>a84 seth.pic seth.obj A84: Assembler for PIC16C84 V1.01 Charles Manning 1996 seth.pic:25 loop BFTSC porta,0 ERROR AT ^ INSTRUCTION: Bad instruction or directive seth.pic:26 BSF portb,0 ERROR AT ^ ARG 1: Need value in range 0..7fh, (0 to 127) seth.pic:27 BCF portb,0 ERROR AT ^ ARG 1: Need value in range 0..7fh, (0 to 127) -------------------------------------------------------------------------------- --- -- Seth Fischer Auckland, New Zealand

>I got my programmer going today and I am trying to assemble a program. >A switch on port A is ment to turn a LED on/off on port B. > >loop BFTSC porta,0 ;if bit 0 porta is set then > BSF portb,0 ;turn on bit 0 port b else > BCF portb,0 ;turn of bit 0 port b > goto loop > >I am using Charles Mannings development system. (same as the Kits R Us >kit, I think) Below is the error message I get. > >Can anyone give me a few tips? Thanks. I can help a little: First, there's a typo: BFTSC should be BTFSC, I think that's why you're getting the "Bad instruction" error. As for the other errors, apparently the assembler doesn't recognize "portb." Did you include the appropriate file for your processor? Second, this program will ALWAYS turn off the led: the BCF instruction will always be executed (there is no "else" here), so if the switch is on, the led will go on for one cycle (too fast to see) then get turned off. Try this: loop bcf potrb, 0 ; always turn led off first btfsc porta, 0 ; if switch is on... bsf portb, 0 ; ...turn led back on goto loop or this: loop btfsc porta, 0 ; if switch is on... bsf portb, 0 ; ...turn led on btfss porta, 0 ; if switch is off... bcf portb, 0 ; ...turn led off goto loop The second one will always take exactly the same amount of time to execute: not important here, but it's worth remembering this structure for later. Hope this helps... Dave Johnson

>I got my programmer going today and I am trying to assemble a program. >A switch on port A is ment to turn a LED on/off on port B. > >loop BFTSC porta,0 ;if bit 0 porta is set then > BSF portb,0 ;turn on bit 0 port b else > BCF portb,0 ;turn of bit 0 port b > goto loop you need to use CAPITAL letters for PORTx. There's also a error in you program! The LED on PORTB will not go on. If PORTA,0 is "1" then the program executes BSF PORTB, 0 AND after that it clears the PORTB, 0 bit again. So your led wil always be off. Have you also set the TRIS register to configure PORTB as an output? bsf STATUS, RP0 ; Select BANK 1 clrf TRISB ; POrtB pins are all outputs bcf STATUS, RP0 Do somthing like this: loop BTFSC PORTA, 0 ; Check if PORTA, 0 is high goto ledon ; Yes it is High bcf PORTB, 0 ; No it is Low goto loop ledon bsf PORTB, 0 goto loop {Quote hidden}>I am using Charles Mannings development system. (same as the Kits R Us >kit, I think) Below is the error message I get. > >Can anyone give me a few tips? Thanks. > >-----------------------------------error >message-------------------------- >C:\Seth\PIC>a84 seth.pic seth.obj >A84: Assembler for PIC16C84 V1.01 > Charles Manning 1996 >seth.pic:25 loop BFTSC porta,0 >ERROR AT ^ >INSTRUCTION: Bad instruction or directive >seth.pic:26 BSF portb,0 >ERROR AT ^ >ARG 1: Need value in range 0..7fh, (0 to 127) >seth.pic:27 BCF portb,0 >ERROR AT ^ >ARG 1: Need value in range 0..7fh, (0 to 127) >--------------------------------------------------------------------------- -------- >-- >Seth Fischer >Auckland, New Zealand

Radboud Verberne wrote: > you need to use CAPITAL letters for PORTx. Only certain assemblers require this. On some assemblers, you can enable case folding which will permit lowercase letters. -- James Cameron (spam_OUTcameronTakeThisOuTstl.dec.com) OpenVMS, Linux, Firewalls, Software Engineering, CGI, HTTP, X, C, FORTH, COBOL, BASIC, DCL, csh, bash, ksh, sh, Electronics, Microcontrollers, Disability Engineering, Netrek, Bicycles, Pedant, Farming, Home Control, Remote Area Power, Greek Scholar, Tenor Vocalist, Church Sound, Husband. "Specialisation is for insects." -- Robert Heinlein.