Help me with code for electronic switch pls

x-land · Jul 13, 2006

I need help with a little code if you can help me.
First I'm sorry for my bad english. I try read in forum but I can't understand nothing. I'm verry n00b in pic programming and in English .

So, I need next aplication (electronic switch) :

I have 1 input (I1) and 4 (O1, O2, O3, O4) outputs.

At input port is 3.3V all time and when push on reset button input is in "0".
I want next:
First situation: If I press reset less 0.5s outputs must be: O1= GND, O2=5V, O3=0 (not GND), O4=0; (if press time is 0.3 for ex. the outputs must be executed)
Second situation: If I press more or equal like 0.5s outputs must be: O1= 0 (not GND), O2=0, O3=GND, O4=5V; (when press time = 0.5s the ouptuts must be executed)

I think 12C508 or 509 is good for what I need but I'm not sure . I have and 5V for Vdd.
I have mikroBasic software. So, if code is for mikroBasic is verry good. I compile them after I have the code. But isn't bad and if is write in asm.

I hope my explication is good

Thanks, thanks, th.........

x-land · Jul 15, 2006

So, I make alone with help tutorial Nigel Goodwin (good tutorial for n00bs) this aplication for 16F628 (it's what I write in my preview post):

Code:

	LIST	p=16F628		
	include "P16F628.inc"		
	__config 0x3D18			


	cblock 	0x20 			
		cnt1 				;for delay routine
		cnt2				;for delay routine
		cnt3				;for delay routine
	endc

		org	0x0000
	
	movlw	0x07
	movwf	CMCON			;turn comparators off (make it like a 16F84)
  	bsf 	STATUS, RP0	
	movlw 	B'00100000'		;set PortA 1 inputs, 7 outputs
   	movwf   TRISA
	bcf		STATUS,	RP0		    
	clrf	PORTA			;set all outputs low
	bsf		PORTA, 4
Loop	btfss PORTA, 5  	;wait for press "reset"
	call short
	goto Loop

short	call Delay       	; delay ~700ms 
  
	btfsc	PORTA, 5		; verify if "reset" is pressed
	call	output1			; if not execute output1
	bsf		PORTA, 0		
	bcf		PORTA, 1		; here I need output GND. I don't know how and if it's possible
	bsf		PORTA, 2			
	bsf		PORTA, 4		; here I need output GND. I don't know how and if it's possible
	goto	finish			; "stop" program, execute countinous loop

output1	bcf PORTA, 0		; here I need output GND. I don't know how and if it's possible
	bsf		PORTA, 1
	bcf		PORTA, 2		; here I need output GND. I don't know how and if it's possible
	bcf		PORTA, 4
	goto	finish

Delay	movlw	3			; delay routine ~700ms
	movwf	cnt3
	movlw	b'11111111'
	movwf	cnt2
	movlw	b'11111111'
	movwf	cnt1
	decfsz	cnt3, F
	goto	$+2
	goto	$+0A
	decfsz	cnt2, F
	goto	$+2
	goto	$+6
	btfsc	PORTA, 5		; verify if "reset" is pressed
	retlw	0x00			; if not return
	decfsz	cnt1, F
	goto	$-1
	goto	$-7
	goto	$-0B
	movlw	b'01111111'
	movwf	cnt2
	movlw	b'11111111'
	movwf	cnt1
	decfsz	cnt2, F
	goto	$+2
	goto	$+6
	btfsc	PORTA, 5		; verify if "reset" is pressed
	retlw	0x00			; if not return
	decfsz	cnt1, F
	goto	$-1
	goto	$-7
	movlw	89
	movwf	cnt1
	decfsz	cnt1, F
	goto	$-1
	retlw	0x00			;return after delay it's over

finish sleep				; stop all, it's enough ;-)
			end

I don't know if is something wrong in them but work .

Now I need if somebody can help me for have at output port Ground (GND) not "0". I don't know if it's possible.
I don't want use transistors for make GND where I need.
And when I build proiect in MPLAB I have this message:
"Message[302] D:\KIT\16F628TEST\TEST1.ASM 18 : Register in operand not in bank 0. Ensure that bank bits are correct."
at line : movwf TRISA
. It's some problem with them?

Thanks

Nigel Goodwin · Jul 15, 2006

x-land said:
And when I build proiect in MPLAB I have this message:
"Message[302] D:\KIT\16F628TEST\TEST1.ASM 18 : Register in operand not in bank 0. Ensure that bank bits are correct."
at line : movwf TRISA
. It's some problem with them?

It's not an error, it's a warning, it's NOT a problem - it's explained in a later tutorial how to prevent it.

x-land · Jul 15, 2006

Thank's. And it's possible have GND at output? Maybe I apear stupid but it's first time when I see pic and assambler. Only positive or negative answer it's enough and I try find solution. I don't want lose the time if isn't possible.
If I read value from one input port what it's at GND and I write that value in output port is that output port at GND?

Nigel Goodwin · Jul 15, 2006

x-land said:
Thank's. And it's possible have GND at output? Maybe I apear stupid but it's first time when I see pic and assambler. Only positive or negative answer it's enough and I try find solution. I don't want lose the time if isn't possible.
If I read value from one input port what it's at GND and I write that value in output port is that output port at GND?

Basically yes, but 'GND' isn't really the correct term, digital I/O pins can be either HIGH or LOW, below a certain voltage means it's LOW, and above a certain voltage means it's HIGH - it doesn't have to be 0V or 5V, there's a logic switching point somewhere in between.

x-land · Jul 15, 2006

I try this with RA4, pin for "open drain output". And I change the input at RA5.
I see it's only one port at 16f628 what can do OD. Is that the solution for what I want? (I change the code in my post with new code). Is real 0V (is pin at Vss?) or is logic "0" when I have bsf PORTA, 4?

mramos1 · Jul 15, 2006

x-land said:
I try this with RA4, pin for "open drain output". And I change the input at RA5.
I see it's only one port at 16f628 what can do OD. Is that the solution for what I want? (I change the code in my post with new code). Is real 0V (is pin at Vss?) or is logic "0" when I have bsf PORTA, 4?

I speak not seening your circuit, but bsf is "Bit Set" so you will have a logic one. It will not be 5 volts, there is a loss from the output of the chip.

bcf porta,4 will send it low. Under a volt, drop a meter on it.. And flip it high and low.

mister_e · Jul 15, 2006

PORTA.4 is an open drain, unless you add a external pull-up resistor, you'll probably never reach the VDD voltage. Mostely noise and wind will go out of there... it's floating in the air.

x-land · Jul 15, 2006

In datasheet at 16F628 pin 3 (RA4) is designed like "open drain output" when is set for output. So, I understand from this when I have bsf porta,4 pin 3 is send in 0. But I don't know if is 0 logic or real 0V (Vss). Maybe I wrong, I don't read good english and I don't write code never but that I understand.
And I try the code live (in circuit) and work like 0V (Vss), but the question remain if is real or not.

Edit: @mister_e: thanks, I write before read your post .

mister_e · Jul 15, 2006

french? if so, drop me a line off list.

x-land · Jul 15, 2006

not french. I'm from Romania

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