CW Keyer using PIC16F628A

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Recently the RnD team made a CW Keyer found in an old magazine.

Name: 73 Magazine
Issue Date: September 1999
Link to Magazine: Here


The CW keyer is simple circuit and uses the PIC16F628A. The components used are very less and can be built a very small general purpose board. This keyer works on the RC Clock and does not require an external crystal. The speed can be varied using the 10K Pot.

List of components used:

10k Resistor              - 3 No.
4.7K Resistor            - 1 No.
10K POT                    - 1 No.
10uF Capacitor         - 2 No.
0.1uF Capacitor        - 1 No.
0.01uF Capacitor      - 2 No.
LM7805 Regulator   - 1 No.
18-Pin Base               - 1 No.
PIC16F628A              - 1 No.
Speaker                      - 1 No.
General Purpose Board

CIRCUIT:

PROGRAM: ASM & HEX


list      p=16F628A          
#include <P16F628a.inc>

__CONFIG       _PWRTE_ON & _RC_OSC_CLKOUT & _WDT_OFF & _MCLRE_ON & _LVP_OFF & _BODEN_OFF & _CP_OFF

COUNT1 equ    028H
COUNT2 equ 029H
COUNT3 equ 02AH

ORG     0x00


movlw 07h
movwf CMCON

start    
bsf STATUS,RP0
movlw b'11111111'  
movwf   TRISA
movlw b'00000000'  
movwf   TRISB
bcf STATUS,RP0

begin  
clrf COUNT1
clrf COUNT2
clrf COUNT3

btfsc PORTA,2
goto dash1
call dot1
goto begin

dash1  
btfsc PORTA,3
goto begin
call dash2
goto begin

dot1
movlw d'12'
movwf COUNT1
redot 
bsf PORTB,3
bcf PORTB,3
decfsz COUNT1,f
goto redot
call pause
return

dash2  
movlw d'37'
movwf COUNT3
redsh  
bsf PORTB,3
bcf PORTB,3
decfsz COUNT3,f
goto redsh
call pause
return

pause  
movlw d'14'
movwf COUNT2
repa  
decfsz COUNT2,f
goto repa
return

end