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| Micro Controllers Discuss all aspects of micro controllers - building them, coding them, etc. All controllers are welcome - PIC, BASIC, Z8 Encore!, etc. |
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26th September 2006, 12:44 PM
| #1 |
 Input Counter Pic16F84A (Code problems)
Hi, My goal with this project i'm working on is to count the number of times a button is pressed in a timespan eg 1 second. These are the 2 approaches i've used that are simulated succesfully, but don't work when put on the chip The first thing i tried is using the interrupt on RB0, when that was triggered it went into a loop for a couple seconds, then every time the interrupt was triggered it incremented a counter and at the end of the delay it used the counter value in a table to get which port to set to high. Again, that worked in my simulations, but not on the chip. The next approach i used was to use Timer0, and increment the counter just using RB0 but not as an interrupt. Put it in a loop looking for Rb0 to go high/low, and when the timer overflowed check the counter value against the table, but again my attempts have failed. Has anyone got any idea as to what i'm obviously missing, as i am fairly new to pic programming. The latest code follows. Code: org 0x00 ;This is where the PC points to on power up & reset ;**********************SETUP CONSTANTS*********************** INTCON equ 0x0B ;Interrupt control register TMR0 equ 0x01 STATUS equ 0x03 ;Banks OPTION_REG equ 0x81 ;Option Reg PC equ 0x02 ;Set Program Counter to 02h for table data TRISA equ 0x85 ;Tristate A PORTA equ 0x05 ;Port A TRISB equ 0x86 ;Tristate B PORTB equ 0x06 ;Port B SWITCHCOUNTER equ 0x0C COUNTER equ 0x0D COUNTER2 equ 0x0E COUNTER3 equ 0x0F TEMP equ 0x10 goto main ;************************INTERRUPT ROUTINE******************* org 0x04 movwf TEMP movlw 0x04 subwf SWITCHCOUNTER,W btfss STATUS,0 goto carry_on goto clear retfie carry_on movf TEMP,w call table movwf PORTA call Delay2 ;This delay is the button press length call ClosePorts call SetVars bcf INTCON,2 retfie clear call SetVars bcf INTCON,2 retfie main ;*****************SETUP INTERRUPT RESGISTERS***************** bsf INTCON,7 ;Set the Global interrupt switch bsf INTCON,5 ;TMR0 interrupt enabled bcf INTCON,2 ;INTF - Clear flag ;**********************SETUP THE PORTS*********************** bsf STATUS,5 ;Switch to bank 1 movlw 0x01 ;Set W to 000001 movwf TRISB ;Put W into TRISB movlw 0x00 ;Set W to 000000 movwf TRISA ;Put W into TRISA movlw b'11010100' movwf OPTION_REG bcf STATUS,5 ;Switch to bank 0 call SetVars intLoop btfss PORTB,0 goto intLoop call Delay3 btfsc PORTB,0 goto $ -1 incf SWITCHCOUNTER call enableInt goto intLoop SetVars clrf TEMP clrf SWITCHCOUNTER movlw 0xFF movwf COUNTER movlw 0xFF movwf COUNTER2 movlw 0xFF movwf COUNTER3 call disableInt return Delay2 Loop2 decfsz COUNTER,1 goto Loop2 decfsz COUNTER2,1 goto Loop2 return Delay3 Loop3 decfsz COUNTER,1 goto Loop3 return ClosePorts bcf PORTA,0 bcf PORTA,1 bcf PORTA,2 return disableInt bcf INTCON,7 bcf INTCON,5 return enableInt clrf TMR0 bcf INTCON,2 bsf INTCON,7 bsf INTCON,5 return table movf SWITCHCOUNTER,w addwf PC,1 retlw 0x00 retlw 0x01 retlw 0x02 retlw 0x04 end | |
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26th September 2006, 01:05 PM
| #2 |
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First off, the 16F84 is LONG! obsolete, it was replaced by the 16F628 last century!. Your interrupt code is very badly flawed, you don't do any context saving and restoring, so it will corrupt your main program. Also, you have THREE 'retfie' instructions, it's good practice to only have one of these. What about key debouncing?, if you don't debounce them you'll get multiple counts for every press. | |
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26th September 2006, 01:12 PM
| #3 |
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yeah  that's the problem living in africa, we're about a century behind everyone else :P I'll look into improving those factors, thank you for your help, this is my first time using interrupts so i'm not all clued up. Let me give these suggestions a bash. Thanks
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26th September 2006, 01:53 PM
| #4 |
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If you check my LED multiplexing tutorials, you'll see examples of context saving and restoring.
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26th September 2006, 02:19 PM
| #5 |
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Ok, as far as i can tell, i've added some debounce code, tidied the interrupt up a bit, it still has 2 retfie's tho. It works with in the simulation, but goes crazy when i put it in the circuit, i have 3 led's hooked up to RA0, RA1 and RA2, the theory is that when i press the button once RA0 lights up for x time, when i press it twice RA1, and 3 times RA2. But in the circuit it doesn't do that at all? The led's just randomly flash for a while, and aren't very responsive to the button presses? Code: org 0x00 ;This is where the PC points to on power up & reset ;**********************SETUP CONSTANTS*********************** INTCON equ 0x0B ;Interrupt control register TMR0 equ 0x01 STATUS equ 0x03 ;Banks PCLATH equ 0x0A OPTION_REG equ 0x81 ;Option Reg PC equ 0x02 ;Set Program Counter to 02h for table data TRISA equ 0x85 ;Tristate A PORTA equ 0x05 ;Port A TRISB equ 0x86 ;Tristate B PORTB equ 0x06 ;Port B SWITCHCOUNTER equ 0x0C COUNTER equ 0x0D COUNTER2 equ 0x0E COUNTER3 equ 0x0F TEMP equ 0x10 s_temp equ 0x11 w_temp equ 0x12 p_temp equ 0x13 goto main ;************************INTERRUPT ROUTINE******************* org 0x04 movwf TEMP movwf w_temp swapf STATUS,W movwf s_temp movfw PCLATH movwf p_temp movlw 0x04 subwf SWITCHCOUNTER,W btfss STATUS,0 goto carry_on goto clear carry_on movf TEMP,w call table movwf PORTA call Delay2 ;This delay is the button press length call ClosePorts call SetVars bcf INTCON,2 movfw p_temp movwf PCLATH swapf s_temp,W movwf STATUS swapf w_temp,f swapf w_temp,W retfie clear call SetVars bcf INTCON,2 movfw p_temp movwf PCLATH swapf s_temp,W movwf STATUS swapf w_temp,f swapf w_temp,W retfie main ;*****************SETUP INTERRUPT RESGISTERS***************** bsf INTCON,7 ;Set the Global interrupt switch bsf INTCON,5 ;TMR0 interrupt enabled bcf INTCON,2 ;INTF - Clear flag ;**********************SETUP THE PORTS*********************** bsf STATUS,5 ;Switch to bank 1 movlw 0x01 ;Set W to 000001 movwf TRISB ;Put W into TRISB movlw 0x00 ;Set W to 000000 movwf TRISA ;Put W into TRISA movlw b'11010100' movwf OPTION_REG bcf STATUS,5 ;Switch to bank 0 call SetVars intLoop btfss PORTB,0 goto intLoop call Delay3 btfss PORTB,0 goto intLoop btfsc PORTB,0 goto $ -1 call Delay3 btfsc PORTB,0 goto $ -1 incf SWITCHCOUNTER call enableInt goto intLoop SetVars clrf TEMP clrf SWITCHCOUNTER movlw 0xFF movwf COUNTER movlw 0xFF movwf COUNTER2 movlw 0xFF movwf COUNTER3 call disableInt return Delay2 Loop2 decfsz COUNTER,1 goto Loop2 decfsz COUNTER2,1 goto Loop2 return Delay3 Loop3 decfsz COUNTER,1 goto Loop3 return ClosePorts bcf PORTA,0 bcf PORTA,1 bcf PORTA,2 return disableInt bcf INTCON,7 bcf INTCON,5 return enableInt clrf TMR0 bcf INTCON,2 bsf INTCON,7 bsf INTCON,5 return table movf SWITCHCOUNTER,w addwf PC,1 retlw 0x00 retlw 0x01 retlw 0x02 retlw 0x04 end | |
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| Tags |
| code, counter, input, pic16f84a, problems |
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