I2c serial eeprom Project
Serial eeprom to PIC16F84 interface
Serial eeprom to PIC16F84 interface
This programm send first a data (F0h) to eeprom at address 00FFh and then data from address 00FFh it's read from eeprom and displayed to portB.
;=======eeprom_i2c / Version 1.0====================17/01/03==
; st24c64w
; ra0,ra1 sdata,sclock
; rb0 to rb7
; internal clock
; standard crystal 4.000 MHz XT - 1us pe instructiune
; Program realizat de Ing. Bergthaller Iulian-Alexandru
;------------------------------------------------------------
list p=16f84A;f=inhx8m
_CP_OFF equ H'3FFF' ;code protect off
_PWRTE_ON equ H'3FFF' ;Power on timer on
_WDT_OFF equ H'3FFB' ;watch dog timer off
_XT_OSC equ H'3FFD' ;crystal oscillator
__CONFIG _CP_OFF & _PWRTE_ON & _WDT_OFF & _XT_OSC
;------------------------------------------------------------
; cpu init
status equ 03
porta equ 05
portb equ 06
count1 equ 0C
count2 equ 0D
count3 equ 0E
transo equ 0F
count4 equ 10
trisa equ 85
trisb equ 86
#DEFINE sclk porta,1
#DEFINE sdta porta,0
;------------------------------------------------------------
; bit init
rp0 equ 5
devicew equ 0xA0
devicer equ 0xA1
;------------------------------------------------------------
org 0
;
;------------------------------------------------------------
init bsf status,rp0 ;switch to bank 1
movlw 0 ;outputs
movwf trisb
bcf status,rp0 ;switch back to bank 0
movlw 0
movwf portb
;***************************************************
start movlw 0xFF
movwf portb
call pause
call scrie
call pause
weit nop
call lesen
call pause
goto weit
;***************************************************
scrie call sout; write datas to address adresl+adresh
movlw 0x00
movwf portb
call alos
bsf portb,0
movlw devicew
movwf transo
call varsa
bsf portb,7
call srin
call antwt ; antwort aus eeprom
call pause
call sout
bcf portb,7
bsf portb,1
movlw 0x00
movwf transo
call varsa
bsf portb,7
call srin
call antwt ; antwort aus eeprom
call pause
call sout
bcf portb,7
bsf portb,2
movlw 0xFF
movwf transo
call varsa
bsf portb,7
call srin
call antwt ; antwort aus eeprom
call pause
call sout
bcf portb,7
bsf portb,3
movlw 0xF0
movwf transo
call varsa
bsf portb,7
call srin
call antwt ; antwort aus eeprom
call pause
call sout
bcf portb,7
bsf porta,3
call ahalt
call pause
bcf porta,3
retlw 00
;***************************************************
lesen call sout
movlw 0x00
movwf portb
call alos
bsf portb,0
movlw devicew
movwf transo
call varsa
bsf portb,7
call srin
call antwt ; antwort aus eeprom
call pause
call sout
bcf portb,7
bsf portb,1
movlw 0x00
movwf transo
call varsa
bsf portb,7
call srin
call antwt ; antwort aus eeprom
call pause
call sout
bcf portb,7
bsf portb,2
movlw 0xFF
movwf transo
call varsa
bsf portb,7
call srin
call antwt ; antwort aus eeprom
call pause
bcf portb,7
bsf portb,3
call sout; current address read
call alos
bsf porta,2
movlw devicer
movwf transo
call varsa
bcf porta,2
call srin
call antwt ; antwort aus eeprom
call scana ; eeprom lesen
call sout
bsf porta,3
call ahalt
call pause
bcf porta,3
retlw 00
;***************************************************
sout bsf status,rp0 ;switch to bank 1
movlw 0 ;outputs
movwf trisa
bcf status,rp0 ;switch back to bank 0
movlw 0
movwf porta
retlw 00
;***************************************************
srin bsf status,rp0 ;switch to bank 1
movlw 01 ;input
movwf trisa; set sda as input
bcf status,rp0 ;switch back to bank 0
retlw 00
;***************************************************
alos bsf sdta; start condition module
bcf sclk
call pause
bsf sclk
call pause
bcf sdta; comanda start
call pause
bcf sclk
call pause
retlw 00
;***************************************************
ahalt bcf sdta; stop condition module
call pause
bsf sclk
call pause
bsf sdta; comanda stop
call pause
bcf sclk
call pause
retlw 00
;***************************************************
varsa bcf sclk
call pause
btfsc transo,7 ;bit0(MSB)
bsf sdta
btfss transo,7
bcf sdta
call pause
bsf sclk
call pause
bcf sclk
call pause
btfsc transo,6 ;bit1
bsf sdta
btfss transo,6
bcf sdta
call pause
bsf sclk
call pause
bcf sclk
call pause
btfsc transo,5 ;bit2
bsf sdta
btfss transo,5
bcf sdta
call pause
bsf sclk
call pause
bcf sclk
call pause
btfsc transo,4 ;bit3
bsf sdta
btfss transo,4
bcf sdta
call pause
bsf sclk
call pause
bcf sclk
call pause
btfsc transo,3 ;bit4
bsf sdta
btfss transo,3
bcf sdta
call pause
bsf sclk
call pause
bcf sclk
call pause
btfsc transo,2 ;bit5
bsf sdta
btfss transo,2
bcf sdta
call pause
bsf sclk
call pause
bcf sclk
call pause
btfsc transo,1 ;bit6
bsf sdta
btfss transo,1
bcf sdta
call pause
bsf sclk
call pause
bcf sclk
call pause
btfsc transo,0 ;bit7(LSB)
bsf sdta
btfss transo,0
bcf sdta
call pause
bsf sclk
call pause
bcf sclk
retlw 00
;***************************************************
scana call pause
bsf sclk
btfsc sdta ;bit0(MSB)
bsf portb,7
btfss sdta
bcf portb,7
bcf sclk
call pause
bsf sclk
btfsc sdta ;bit1
bsf portb,6
btfss sdta
bcf portb,6
bcf sclk
call pause
bsf sclk
btfsc sdta ;bit2
bsf portb,5
btfss sdta
bcf portb,5
bcf sclk
call pause
bsf sclk
btfsc sdta ;bit3
bsf portb,4
btfss sdta
bcf portb,4
bcf sclk
call pause
bsf sclk
btfsc sdta ;bit4
bsf portb,3
btfss sdta
bcf portb,3
bcf sclk
call pause
bsf sclk
btfsc sdta ;bit5
bsf portb,2
btfss sdta
bcf portb,2
bcf sclk
call pause
bsf sclk
btfsc sdta ;bit6
bsf portb,1
btfss sdta
bcf portb,1
bcf sclk
call pause
bsf sclk
btfsc sdta ;bit7(LSB)
bsf portb,0
btfss sdta
bcf portb,0
bcf sclk
call pause
bsf sclk
call pause
bcf sclk
retlw 00
;***************************************************
antwt movlw 0x04
movwf count4
bsf sclk
call pause
ackts btfss sdta ;sda=0 ?
goto eprok
decfsz count4
goto ackts
call fails
eprok bcf sclk
retlw 00
;***************************************************
fails movlw 0
movwf portb
call pause
movlw 0xFF
movwf portb
call pause
movlw 0
movwf portb
call pause
retlw 00
;***************************************************
pause movlw 0x02
movwf count3
d3 movlw 0xF0
movwf count1
d1 movlw 0xF0
movwf count2
d2 decfsz count2
goto d2
decfsz count1
goto d1
decfsz count3
goto d3
retlw 00
;------------------------------------------------------------
end
;============================================================
The hex code can be download from here.
The last version it's now available.
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