4x3 alphanumeric keypad

[brennbar67]

alphanumeric keypad interfacing

Does anyone know how write a program that able to display the character keyed by the keypad??
Anyone got the c-source code or the assembly code??
If you can send me the material, is it much appreciated...

 

[SPATAN]

4x3 keyboard pic

I used pic controller. but 4X4 key

;**********************************************
; STEP to follow when test this program
; 1.Connect RS232 or RS422 cable between board and PC.
; 2.Download this program to CPU.
; 3.Run terminal program such as Procom plus,XTALK etc.
; 4.Set parameter Procom plus to 9600 baud,No parity,8 bits data and 1 bit. stop
; 5.Connect Keyboard 4x4 to KBI/IO on board CP-PIC V4.0
; RB4 connect row 1
; RB5 connect row 2
; RB6 connect row 3
; RB7 connect row 4
; RD0 connect column 1
; RD1 connect column 2
; RD2 connect column 3
; RD3 connect column 4
; 6.Press any key on keyboard, you will see the key that you pressed.
;**********************************************

list p=16f877 ; list directive to define processor
#include <p16f877.inc> ; processor specific variable definitions

count EQU 0x21
colm EQU 0x22
dt1 EQU 0x23
dt2 EQU 0x24
dt3 EQU 0x25

ORG 0x0000

;************ initial *******************

init bsf STATUS,RP0 ; select bank 1
clrf TRISD
movlw 0xff
movwf TRISB
bcf OPTION_REG,7
movlw 0x40 ; BAUD rate 9600
movwf SPBRG
clrf TXSTA ; 8 bits data ,no,1 stop

bcf STATUS,RP0 ; select bank 0
bsf RCSTA,SPEN ; Asynchronous serial port enable
bsf RCSTA,CREN ; continuous receive

bsf STATUS,RP0 ; select bank 0
bsf TXSTA,TXEN ; Transmit enable
BSF TXSTA,BRGH ; HI SPEED
bcf STATUS,RP0 ; select bank 0
;********** start to send **********************
scan movlw 0xfe ; start scan column 1
movwf colm
clrf count ; clear counter
scan1 movf colm,w ; scan column
movwf PORTD
btfss PORTB,4 ; check RB4
goto sw_1
btfss PORTB,5 ; check RB5
goto sw_2
btfss PORTB,6 ; check RB6
goto sw_3
btfss PORTB,7 ; check RB7
goto sw_4
movlw .4
clrc ; clear carry flag
addwf count,f
clrc
rlf colm,f ; rotate scan
btfsc colm,4 ; check last column
goto scan1
goto scan ; start scan

sw_4 incf count,f
sw_3 incf count,f
sw_2 incf count,f
sw_1 movf count,w

call TAB
call send ; Send data to RS232
call delay
goto scan ; Back to scan

send movwf TXREG ; Send recent data to TX
wait1 movlw TXSTA ;
movwf FSR
btfss INDF,1 ; check TRMT bit in TXSTA (FSR)
goto wait1 ; TXREG full or TRMT = 0
return

delay movlw 3 ; delay
movwf dt1
sd3 clrf dt2
sd2 clrf dt3
sd1 decfsz dt3
goto sd1
decfsz dt2
goto sd2
decfsz dt1
goto sd3
return

;********* Tebel of message ********************

TAB addwf PCL,f ; Move offset to PC lower

DT "0","1","2","3","4","5","6","7","8","9","A","B","C","D","E","F"

 

[metao]

4x3 alphanumeric keypad price list

Read Appplication Note AN234
Hardware Techniques for PICmicro Microcontrollers
From Microchip
You will can Read 20 Key from 1 pin
(A2D)

 

[zhangjl]

alphanumeric keypad code download

There are many mcu application books can find it.

 

[metao]

alphanumeric keypad c code

Link
https://ww1.microchip.com/downloads/en/AppNotes/00234a.pdf

good Design for make keyboard and led driver