Post by thread:simple polling

Hello, I have just gone through doing a led flasher and now moving to learn how to use input on the PIC16f84. I am trying to get this piece of code working. It is SUPPOSED to keep on led on pin RB1, then when pin RB0 = low, led on RB2 is lit. This code was originally got from http://www.rentron.com/Myke5.htm but that did not even work. So, I changed it and it still does not work! I tried it on the MLAB simulator and it seems to be working as I want it? Any body see anything wrong? Thanks for the help, Sep S. ==== #include "p16f84.inc" LIST P=16F84, R=DEC ; Register Usage (nothing there...) CBLOCK 0x00C ; Start Registers at End of the Values ENDC __CONFIG _CP_OFF & _XT_OSC & _PWRTE_ON & _WDT_OFF ; Note that the WatchDog Timer is OFF ; Note: B0 : mommentarily on push button ; B1 : lit at all times! ; B2 : lit if button is being pushed ORG 0 BSF STATUS,RP0 ; select bank 1 (need to go to bank 1 since trisb is there!) MOVLW 0x01 ; turn b0:input, b1,2:output MOVWF TRISB ; apply it to trisb register BCF STATUS,RP0 ; select bank 0 (come back!) BSF PORTB,1 ; turn on led on B1 (and keep lit) Loop BTFSC PORTB,0 ; Is the Button Pressed? GOTO ButtonPressed ; turn it on .... BCF PORTB,2 ; Turn off LED B2 off GOTO Loop ButtonPressed ; Button Pressed, Turn LED on BSF PORTB,2 GOTO Loop END ; end it...

Sep, -----Original Message----- From: sep <spam_OUTsseyediTakeThisOuThypervr.com> To: .....PICLISTKILLspam@spam@MITVMA.MIT.EDU <PICLISTKILLspamMITVMA.MIT.EDU> Date: Saturday, February 05, 2000 7:47 PM Subject: simple polling |Hello, | |I have just gone through doing a led flasher and now moving to learn how to |use input on the PIC16f84. I am trying to get this piece of code working. It |is SUPPOSED to keep on led on pin RB1, then when pin RB0 = low, led on RB2 |is lit. |This code was originally got from http://www.rentron.com/Myke5.htm but that |did not even work. So, I changed it and it still does not work! | |I tried it on the MLAB simulator and it seems to be working as I want it? | | |Any body see anything wrong? | | | |Thanks for the help, | |Sep S. | |==== |#include "p16f84.inc" | | LIST P=16F84, R=DEC | | | ; Register Usage (nothing there...) | CBLOCK 0x00C ; Start Registers at End of the Values | ENDC | | | __CONFIG _CP_OFF & _XT_OSC & _PWRTE_ON & _WDT_OFF | ; Note that the WatchDog Timer is OFF | | | ; Note: B0 : mommentarily on push button | ; B1 : lit at all times! | ; B2 : lit if button is being pushed | | | ORG 0 | | BSF STATUS,RP0 ; select bank 1 (need to go to bank 1 since trisb is there!) | MOVLW 0x01 ; turn b0:input, b1,2:output | MOVWF TRISB ; apply it to trisb register | BCF STATUS,RP0 ; select bank 0 (come back!) | BSF PORTB,1 ; turn on led on B1 (and keep lit) | |Loop | BTFSC PORTB,0 ; Is the Button Pressed? Note that, as You said in the lines above, with the button pressed You have a '0' in RB0 pin. In this case, You will need to use the instruction BTFSS in place of BTFSC, to mantain the LED off while the button is not pressed ('1' logic because of the pull-up in pin RB0 I assume You've connected in the pin) | GOTO ButtonPressed ; turn it on .... | BCF PORTB,2 ; Turn off LED B2 off | GOTO Loop | |ButtonPressed ; Button Pressed, Turn LED on | BSF PORTB,2 Here You must add a delay to see the LED on (with hundreds of ms. You will see it clearly), and to "software debounce" the swith. | GOTO Loop | | END ; end it... Regards, S.-