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 Elektor,EPE,Silicon Chip

2 Digit Up/Down Counter with PIC12F628
and prototype PC board $25.00 plus $5.00 postage.
 To order the kit,  send an email to us and we will reply with the details of how to order etc.

P1 2 digit Up/Down Counter using PIC16F628
P2  adding Dice and Random Number (PIC16F628)
P3  2 digit Up/Down Counter using PIC12F629
P4  adding RF Link to PIC12F629 version
P5 Car Gears Up/Down counter
 

 

Up/Down Counter using a PIC12F629
To take our programming skills further, we can use a PIC12F629 chip to produce a 2-Digit Up/Down Counter.
It might seem impossible to convert a project using an 18 pin chip to an 8-pin micro, but by using multiplexing skills and placing 2 buttons on the input-ONLY line of the chip, we can achieve this.
Most of the program sets up the drive-lines to access the segments. The actual part of the program that produces the "effect" is contained in the Main routine.
The PC board has two 7-segment displays made up of individual LEDs. Each segment consists of 2 LEDs in series. These are placed on an output line so that when the line is HIGH, one segment is illuminated, and when it is LOW, another segment is illuminated.
This allows the micro to illuminate 6 segments with 3 drive-lines.
The circuit is then made more complex by including a set of 4 transistors to select the left-hand or right-hand display.
This requires 2 more drive-lines.
The last line is an input-ONLY line and is used for the buttons.
Segment "g" is driven directly from the transistors in a similar way to an "H-bridge" where two diagonally opposite transistors turns on to produce a drive for the left-hand "g" segment and the other two diagonally opposite transistors turn on for the other "g" segment.
This project is merely a "conceptual" design to prove that noting is impossible in electronics.
PIC chips are less than 50 cents in large qualities and all the other components are less than 1 cent each.
This makes the project viable as the display is 50% larger and cheaper than using 7-segment displays.
The whole aim of the project is to learn programming and interfacing the micro to the outside world.


PIC12F629 2-Digit Counter


How the circuit works
 There are a few interesting features in this circuit and they need some explaining.
The first is the illuminating of the LEDs. By connecting 2 LEDs in series and using a 5.5v supply, we can illuminate two LEDs for each segment.
The LEDs are connected to the positive rail via a transistor. This transistor is an NPN device and is acting as an emitter-follower so that when output GP0 or GP5 of the micro is HIGH, the emitter will deliver current to the LEDs via the collector-emitter circuit. The voltage at the emitter is 0.6v less than the base and the micro will rise to nearly rail voltage (about 0.3v below rail voltage), so the positive voltage is approx 6v - 0.6v - 0.6v - 0.3v = 4.5v
The cathode of the LED-pair is connected to one of the output lines GP1, GP2 or GP4 and the voltage on the line will be approx 0.3v. This will provide a supply voltage of approx 4.2v and illuminate the two LEDs. Each LED has a natural voltage drop of approx 1.9v so you can't allow the battery voltage to drop very much before the display will fail to work. The 47R resistor limits the current though the LEDs.
 
When a drive-line GP1, GP2 or GP4 is taken HIGH, output GP0 or GP5 of the micro must be LOW to allow the other two LEDs will be illuminated.
To illuminate each segment, the input/output for each line must be allocated to the TRISIO register and each line must be allocated HIGH or LOW if it is an output. The combination of segments produces a digit on either the left display or right display and the instructions are contained in a separate sub-routine.
Once the sub-routine for each character (digit) has been worked out, the program from the previous project was pasted into the program and the only instructions needed changing were those that applied to the output port.
Two separate tables are needed; one for the left display and one for the right display.
The tables have a "goto" instruction at the beginning of each line so that the micro goes immediately to the sub-routine corresponding the chosen digit for either the left or right display. The sub-routine for each digit contains the "retlw" command, to send the micro back to the Main routine.
The project has been produced on Experimental board using surface-mount components with yellow LEDs for the display.  It is not for beginners, however a kit of components is available from Talking Electronics for $15.00 plus $5.00 postage. The board must be adapted for the project and this requires cutting 10 of the tracks and fine enamelled wire to connect the components to the micro.
 


The PIC12F629 2-Digit Counter
 Cut 10 tracks as shown in the layout below, so the board suits this project.

 
                            Layout for 2 Digit Up/Down Counter
               Cut 10 tracks as shown in the layout above, so the board suits this project.

The files:
12F629Counter.asm
12F629Counter.hex
12F629Counter.txt
12F629Counter-h.txt
NotePad2-exe
NotePad2.zip
MPASM  - this file comes on the CD with PICkit-2
PICkit-2  - this "burning" or "programming program" on the CD with PICkit-2.
 
The program below is the assembly program. This is for viewing ONLY. To modify the program you will need to load this file: 12F629Counter.asm into NotePad2 and make the changes.
The .asm is then compiled via MPASM to produce a .hex file for PICkit-2.

Set up your desktop as follows, with a folder called PICkit-2 files. Inside this folder you can have other folders such as PIC12F629 Counter; then an icon for MPASM and an icon for PICkit-2:


 

	
	;2Digit Counter   12F629.asm
	;  13-6-2009 

	list	p=12F629
	radix	dec
	include	"p12f629.inc"
	
	errorlevel  -302  ;Dont complain about BANK 1 Reg during assembly

	__CONFIG	_MCLRE_OFF & _CP_OFF & _WDT_OFF 
			& _INTRC_OSC_NOCLKOUT  ;Internal osc.


temp1		equ 	20h	;
temp2		equ 	21h	;
temp3		equ 	22h	;
SwUp		equ	23h	;
SwDwn		equ	24h	;
units		equ	25h	;
tens		equ	26h	;
Sw_Flag		equ	27h	;
FastCount	equ	28h	;
Count		equ	29h	; counting 00 to 99
File5mS		equ 	2Ah 	;
FileXmS		equ 	2Bh 	;

;****************************************************************
;Equates
;****************************************************************
status		equ	0x03
rp1		equ	0x06
rp0		equ	0x05
portA 		equ 	0x05
portB 		equ 	0x06

status		equ	03h
option_reg	equ 	81h

		; bits on GPIO
			
pin7	equ	0	;GP0  
pin6	equ	1	;GP1
pin5	equ	2	;GP2 
pin4	equ	3	;GP3 input only
pin3	equ	4	;GP4 
pin2	equ	5	;GP5 

		;bits
				
rp0	equ	5		;bit 5 of the status register
		

Start	org	0x00		;program starts at location 000
		nop
		nop
		nop
		nop		;NOPs to get past reset vector address
		nop
		nop


			;set up to allow counting from external oscillator

SetUp	bsf	status, rp0 	;Bank 1	
	movlw	b'11110111'	;Turn on T0CKI, prescale for TMR0 = 1:256
	movwf	option_reg
       	bcf	status, rp0	;bank 0   
	movlw   07h        	;Set up W to turn off Comparator ports
        movwf   CMCON       	;must be placed in bank 0  
	clrf 	GPIO       	;Clear GPIO of junk
	clrf 	units		
	clrf 	tens
	clrf	Sw_Flag		
	goto 	Main			
	

Table1	addwf	02,1	;Add W to the Program Counter to create a jump
	goto	showX0	;the zero on the right-hand display	
	goto	show01
	goto	show02
	goto	show03
	goto	show04
	goto	show05
	goto	show06
	goto	show07
	goto	show08
	goto	show09
		
Table2	addwf	02,1	;Add W to the Program Counter to create a jump
	goto	show0X 	;the zero on the left-hand display	
	goto	show10
	goto	show20
	goto	show30
	goto	show40
	goto	show50
	goto	show60
	goto	show70
	goto	show80
	goto	show90
		
	;Delay 0.005 sec (5mS)

_5mS	movlw 	05h
	movwf 	File5mS	
Del5mS	nop
	decfsz 	FileXmS,1	; ,1 denotes the result of the decrement 
	goto 	Del5mS	
	decfsz 	File5mS,1	;     is placed in the file	
	goto 	Del5mS
	retlw 	00

FastUp	btfss	Sw_Flag,2	;First time through loop?
	goto	FU_2		;yes
	btfsc	Sw_Flag,7	;Has 5Hz bit been set?
	goto	FU_3
FU_1	incfsz	FastCount,1	;Increment FastCount
	movlw	d'50'		;determines the time before fast incrementing
	xorwf	FastCount,0
	btfss	status,2	;reached 50 loops?
	retlw	00
	clrf	FastCount
	bsf	Sw_Flag,7	;set bit for 5Hz incrementing	
		

FU_2	bsf	Sw_Flag,2	;Up button has been pressed
	incf	units,1
	movlw	0Ah		;put 10 into w
	xorwf	units,0		;compare units file with 10
	btfss	status,2	;zero flag in status file. Set if units is 10
	retlw	00
	clrf	units
	incf	tens,1
	movlw	0Ah		;put 10 into w
	xorwf	tens,0		;compare units file with 10
	btfsc	status,2	;zero flag in status file. Set if tens is 10
	clrf	tens				
	retlw	00		;display passes 99 but not below 0
		
		
FU_3	incfsz	FastCount,1	;Increment FastCount
	movlw	d'5'		;Determines the speed of the increments
	xorwf	FastCount,0
	btfss	status,2	;reached 5 loops?
	retlw	00
	clrf	FastCount		
	goto	FU_2			
		
Dwn	btfsc	Sw_Flag,3
	retlw	00
	bsf	Sw_Flag,3
	decf	units,1
	movlw	0FFh		;put FFh into w
	xorwf	units,0		;compare units file with FFh
	btfss	status,2	;zero flag in status file. Set if units is 10
	retlw	00
	movlw	09
	movwf	units		;put 9 into units file
	decf	tens,1
	movlw	0FFh		;put 0FFh into w
	xorwf	tens,0		;compare tens file with 0FFh
	btfsc	status,2	;zero flag in status file. Set if tens is 0FFh
	goto	$+2		;tens file is 0FFh
	retlw	00						
	clrf	tens
	clrf	units
	retlw	00		;display  not below 0			
		
show01	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00011001'	;Set TRIS  to show seg B
	movwf	TRISIO	   	;	
	bcf	status, rp0	;bank 0  
	movlw	b'00100101'	;   
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
       	movlw	b'10010011'	;Set TRIS to show seg C
	movwf	TRISIO	   	;	
	bcf	status, rp0	;bank 0  		
	movlw	b'00000110'		;   
	movwf	GPIO
	call 	_5mS			
	retlw 	00			
		
show02	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00000101'	;Set TRIS  to show seg A & E
	movwf	TRISIO	       	;	
	bcf	status, rp0	;bank 0  
	movlw	b'00010111'	;   
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
       	movlw	b'10011000'	;Set TRIS to show seg B & D & G
	movwf	TRISIO	   	;	
	bcf	status, rp0	;bank 0  		
	movlw	b'00100000'	   
	movwf	GPIO
	call 	_5mS						
	retlw 	00				
		
show03	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00010001'	;Set TRIS  to show seg A & C
	movwf	TRISIO	   		
	bcf	status, rp0	;bank 0  
	movlw	b'00010111'   
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10011000'	;Set TRIS to show seg B & D & G  
	movwf	TRISIO	   		
	bcf	status, rp0		;bank 0  		
	movlw	b'00100000'	   
	movwf	GPIO
	call 	_5mS						
	retlw 	00		
		
		
show04	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00010011'	;Set TRIS  to show seg  C
	movwf	TRISIO	   		
	bcf	status, rp0	;bank 0  
	movlw	b'00010111'	   
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10001100'	;Set TRIS to show seg B & F & G
	movwf	TRISIO	   	
	bcf	status, rp0	;bank 0  		
	movlw	b'00100000'	   
	movwf	GPIO
	call 	_5mS							
	retlw 	00			

show05	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00010001'	;Set TRIS  to show seg A & C
	movwf	TRISIO	   		
	bcf	status, rp0	;bank 0  
	movlw	b'00010111'	   
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10001010'	;Set TRIS to show seg D & F & G
	movwf	TRISIO	   		
	bcf	status, rp0	;bank 0  		
	movlw	b'00100000'	   
	movwf	GPIO
	call 	_5mS						
	retlw 	00			
				
show06	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00000001'	;Set TRIS  to show seg A & C & E
	movwf	TRISIO	   	
	bcf	status, rp0	;bank 0  
	movlw	b'00010111'
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10001010'	;Set TRIS to show seg D & F & G
	movwf	TRISIO	   	
	bcf	status, rp0	;bank 0  		
	movlw	b'00100000'	   
	movwf	GPIO
	call 	_5mS						
	retlw 	00			
				
show07	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00010001'	;Set TRIS  to show seg A & C
	movwf	TRISIO	   		
	bcf	status, rp0	;bank 0  
	movlw	b'00010111'	   
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10011101'	;Set TRIS to show seg B
	movwf	TRISIO	   	 
	bcf	status, rp0	;bank 0  		
	movlw	b'00100000'	  
	movwf	GPIO
	call 	_5mS						
	retlw 	00			
				
show08	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00000001'	;Set TRIS  to show seg A & C & E
	movwf	TRISIO	   	 	
	bcf	status, rp0	;bank 0  
	movlw	b'00010111'	  
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10001000'	;Set TRIS to show seg B & D & F & G
	movwf	TRISIO	   	   	
	bcf	status, rp0	;bank 0  		
	movlw	b'00100000'		
	movwf	GPIO
	call 	_5mS						
	retlw 	00			
				
show09	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00010001'	;Set TRIS  to show seg A & C
	movwf	TRISIO	   	 	
	bcf	status, rp0	;bank 0  
	movlw	b'00010111'	  
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10001000'	;Set TRIS to show seg B & D & F & G
	movwf	TRISIO	   		
	bcf	status, rp0	;bank 0  		
	movlw	b'00100000'	
	movwf	GPIO
	call 	_5mS						
	retlw 	00			
				
showX0	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00000001'	;Set TRIS  to show seg A & C & E
	movwf	TRISIO	   	
	bcf	status, rp0	;bank 0  
	movlw	b'00010111'	
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10001001'	;Set TRIS to show seg B & D & F 
	movwf	TRISIO	   	  	
	bcf	status, rp0	;bank 0  		
	movlw	b'00100000'	
	movwf	GPIO
	call 	_5mS							
	retlw 	00			
		
show0X	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00100000'	;Set TRIS  to show seg A & C & E
	movwf	TRISIO	   	  	
	bcf	status, rp0	;bank 0  
	movlw	b'00010110'	   
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10101000'	;Set TRIS to show seg B & D & F 
	movwf	TRISIO	   	
	bcf	status, rp0	;bank 0  		
	movlw	b'00100001'	   
	movwf	GPIO
	call 	_5mS							
	retlw 	00			
							
show10	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00111000'	;Set TRIS  to show seg B
	movwf	TRISIO	   		
	bcf	status, rp0	;bank 0  
	movlw	b'00100101'	  
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
       	movlw	b'10110010'	;Set TRIS to show seg C
	movwf	TRISIO	   	 
	bcf	status, rp0	;bank 0  		
	movlw	b'00000110'	
	movwf	GPIO
	call 	_5mS			
	retlw 	00						
					
show20	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00100100'	;Set TRIS  to show seg A & E
	movwf	TRISIO	   		
	bcf	status, rp0	;bank 0  
	movlw	b'00010110'	
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
       	movlw	b'10011000'	;Set TRIS to show seg B & D & G
	movwf	TRISIO	   	
	bcf	status, rp0	;bank 0  		
	movlw	b'00000001'	
	movwf	GPIO
	call 	_5mS							
	retlw 	00
		
show30	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00110000'	;Set TRIS  to show seg A & C
	movwf	TRISIO	   	 	
	bcf	status, rp0	;bank 0  
	movlw	b'00010110'	
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10011000'	;Set TRIS to show seg B & D & G
	movwf	TRISIO	   	   	
	bcf	status, rp0	;bank 0  		
	movlw	b'00000001'		
	movwf	GPIO
	call 	_5mS							
	retlw 	00		
				
show40	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00110010'	;Set TRIS  to show seg  C
	movwf	TRISIO	   		
	bcf	status, rp0	;bank 0  
	movlw	b'00010110'	
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10001100'	;Set TRIS to show seg B & F & G
	movwf	TRISIO	   	
	bcf	status, rp0	;bank 0  		
	movlw	b'00000001'	
	movwf	GPIO
	call 	_5mS						
	retlw 	00			
		
show50	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00110000'	;Set TRIS  to show seg A & C
	movwf	TRISIO	   	 	
	bcf	status, rp0	;bank 0  
	movlw	b'00010110'	   
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10001010'	;Set TRIS to show seg D & F & G
	movwf	TRISIO	   	   	
	bcf	status, rp0	;bank 0  		
	movlw	b'00000001'		
	movwf	GPIO
	call 	_5mS							
	retlw 	00		
		
show60	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00100000'	;Set TRIS  to show seg A & C & E
	movwf	TRISIO	   		
	bcf	status, rp0	;bank 0  
	movlw	b'00010110'	  
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10001010'	;Set TRIS to show seg D & F & G
	movwf	TRISIO	   	 	
	bcf	status, rp0	;bank 0  		
	movlw	b'00000001'	  
	movwf	GPIO
	call 	_5mS						
	retlw 	00		
							
show70	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00110000'	;Set TRIS  to show seg A & C
	movwf	TRISIO	   	
	bcf	status, rp0	;bank 0  
	movlw	b'00010110'	   
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10111100'	;Set TRIS to show seg B
	movwf	TRISIO	   	 	
	bcf	status, rp0	;bank 0  		
	movlw	b'00000001'	   
	movwf	GPIO
	call 	_5mS							
	retlw 	00	
		
show80	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00100000'	;Set TRIS  to show seg A & C & E
	movwf	TRISIO	   		
	bcf	status, rp0	;bank 0  
	movlw	b'00010110'	  
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10001000'	;Set TRIS to show seg B & D & F & G
	movwf	TRISIO	   	 	
	bcf	status, rp0	;bank 0  		
	movlw	b'00000001'	
	movwf	GPIO
	call 	_5mS						
	retlw 	00		
		
show90	
	bsf	status, rp0 	;Bank 1			
       	movlw	b'00110000'	;Set TRIS  to show seg A & C
	movwf	TRISIO	   		
	bcf	status, rp0	;bank 0  
	movlw	b'00010110'	   
	movwf	GPIO		
	call 	_5mS
	bsf	status, rp0 	;Bank 1			
	movlw	b'10001000'	;Set TRIS to show seg B & D & F & G
	movwf	TRISIO	   	   	
	bcf	status, rp0	;bank 0  		
	movlw	b'00000001'	  
	movwf	GPIO
	call 	_5mS							
	retlw 	00							
		
		
;****************************************************************
;* Main 							*
;****************************************************************

Main	bsf	status, rp0 	;Bank 1			
       	movlw	b'11111101'	;Set TRIS  
	movwf	TRISIO	   		
	bcf	status, rp0	;bank 0 		
	movlw	b'00000000'	;Set GP1 low  
	movwf	GPIO
	btfsc	GPIO,3
	call	FastUp		;UP switch pressed
	bsf	status, rp0 	;Bank 1			
       	movlw	b'11111101'	;Set TRIS  
	movwf	TRISIO	   	 	
	bcf	status, rp0	;bank 0 		
	movlw	b'00000010'	;Set GP1 High 
	movwf	GPIO
	btfss	GPIO,3		;down produces 90
	call	Dwn		;Down switch pressed
	clrf	GPIO
	movf	units,0		;copy unit value into w
	call	table1		;unit display value will return in w
	movf	tens,0		;copy tens value into w		
	call	table2		;tens display value will return in w
	bsf	status, rp0 	;Bank 1			
       	movlw	b'11111101'	;Set TRIS  
	movwf	TRISIO	   	 	
	bcf	status, rp0	;bank 0 		
	movlw	b'00000010'	;Set GP1 High 
	movwf	GPIO
	btfsc	GPIO,3		;bit will be zero when sw is pressed - down
	bcf	Sw_Flag,3	;button not pressed. Clear down flag
	bsf	status, rp0 	;Bank 1			
       	movlw	b'11111101'	;Set TRIS  
	movwf	TRISIO	   	 	
	bcf	status, rp0	;bank 0 		
	movlw	b'00000000'	;Set GP1 low  Testing for UP switch
	movwf	GPIO
	btfsc	GPIO,3		;UP will be High when pressed
	goto	Main		
	bcf	Sw_Flag,2	;button not pressed. Clear Up flag
	bcf	Sw_Flag,7	;Clear Up repeat flag
	clrf	FastCount
	goto	Main					
		
		;oscillator calibration
	call 	03ffh
	movwf	OSCCAL		

	end
 

PARTS LIST
PIC12F629 version
with SM LEDs

RESISTORS
(All surface mount 1/10th watt)
5 - 47R marked as 470
1 - 1k    "          "   102
1 - 22k    "          "    223

CAPACITORS
1 - 100n surface mount
1 - 10u tantalum surface mount (106)

 SEMICONDUCTORS
1 - surface mount diode 1N4148  (a6p)
2 - BC847  - surface mount (1F)
2 - BC856  - surface mount  (3B)
1 - PIC12F629 Micro (00-99 Counter)

1 - on/off slide switch
2 - tactile switches
1 - 8 pin IC socket
5 - machine pins
28 - yellow surface mount LEDs  (30)

Orange screen 4.5cm x 3cm
30cm - fine solder
20cm - fine tinned copper wire
50cm - 0.025mm enamelled wire

1 -  2 Digit Counter PC Board
                (Experimenter Board)


You will also need the 6 pin to 5 pin adapter for "In Circuit Programming" to connect between the PICkit-2 programmer and the Project ($1.50): A PC board is being produced for the adapter.


GOING FURTHER
Now that you know how to access each of the segments i the left and right displays, you can produce all sots of programs.
Some of the ideas we have in the pipeline include a timer. How many times have you burnt something or forgotten to ring someone back after an hour?
This handy timer has a few buttons and by simply pressing a button it will count down and sound a piezo when the time has expired.
This will be one of the next projects but you can get in first and try your hand at programming.
All you need do is add a buffer to drive a piezo and since all the lines are fully occupied, this will require a clever bit of interfacing.
I will give you a clue how to do it.
The output of one of the lines will contain a delay circuit (say 0.2 second) and when this is kept low, the other line can be used to drive the buffer transistor, as shown in the following diagram:

To order the kit,  send an email to us and we will reply with the details of how to order etc.


If you have any questions on how the circuit works or how to add different features, email the author and your answer will be posted here:

 

P1   P2  P3  P4(RF Link) P5


  20/6/09