;==================================================================
; Purpose:
;
; This application note is intended to serve as a reference for
; communicating with Microchip’s I2C serial EEPROM devices with the
; use of the PICmicro MSSP module.
;==================================================================
; ПРОГРАМА ЗА I2C ОБМЕН
; Използва се апаратен протокол чрез шини
; RC3 - CLOCK
; RC4 - DATA
; Port C pin descriptions
; SCL bit = 3
; SDA bit = 4
;==================================================================
; 4Mhz - кварц - това има значение за определяне на четотата за I2C
; DS1307
;
;
;
;=============================================================================
LIST P=16F873 ; LIST DIRECTIVE TO DEFINE PROCESSOR
#INCLUDE <P16F873.INC> ; PROCESSOR SPECIFIC VARIABLE DEFINITIONS
ERRORLEVEL -302 ; SUPPRESS BANK SELECTION MESSAGES
__config _cp_ALL & _wdt_off & _BODEN_ON & _pwrte_on & _hs_osc & _LVP_OFF & _DEBUG_OFF & _CPD_OFF
;=============================================================================
;===================RAM register definitions======================
CBLOCK H'20'
datai ;20h Data input byte buffer
datao ;21h Data output byte buffer
bytecount ;22h Counter for byte loops
pollcnt ;23h Counter for polling loops
loops ;24h Delay loop counter
loops2 ;25h Delay loop counter
SDATA
ADRESS
HOUR_H
HOUR_L
MIN_H
MIN_L
SEC_H
SEC_L
DAY_H
DAY_L
MONTH_H
MONTH_L
YEAR_H
YEAR_L
TEMP
NOTEMP
DLAY
DD1
DD2
DD3
d1
d2
d3
ENDC
;===================Macro definitions=============================
WRITE_ADDR equ H'D0' ; Control byte for write operations
READ_ADDR equ H'D1' ; Control byte for read operations
;===================Include file==================================
; MACROS
BANK0 MACRO
BCF STATUS,RP0
BCF STATUS,RP1
ENDM
BANK1 MACRO
BSF STATUS,RP0
BCF STATUS,RP1
ENDM
;================================================================
; НАЧАЛО НА ПРОГРАМАТА
;================================================================
ORG H'0' ; RESET VECTOR LOCATION
GOTO START ; Go to the beginning of main
;===================Begin Main Program============================
START
CALL DELAY1S ;изчакване на 1 сек за установяване на системата
BANK1
MOVLW H'07'
MOVWF ADCON1 ; AN0-AN7 - DIGITAL INPUTS
BANK0
;==========================================================
CLRF PORTC
MOVLW B'00000000'
MOVWF PORTB
CLRF PORTA
;==================== PORT A ==============================
BANK1
MOVLW B'00010111' ; RA0-PA3,RA5 - ВХОДОВЕ
MOVWF TRISA ; RA4- ИЗХОД
;==================== PORT B ==============================
MOVLW B'00000000' ;RB7-RB0 - ИЗХОДИ
MOVWF TRISB ;
;==================== PORT C ==============================
MOVLW B'11111111' ;RC0-RC7 - ВХОДОВЕ
MOVWF TRISC
;==========================================================
MOVLW B'0001111' ;Prescaler Rate=256, PULL-up ENABLE
MOVWF OPTION_REG
BANK0
CLRF INTCON
;==========================================================
CLRF PORTA
CLRF PORTC
CLRF PORTB
;==========================================================
; Нулирана на константите
; Нулира се адресното поле H'20' - H'7F'
;==========================================================
MOVLW H'20'
MOVWF FSR
CL
CLRF INDF
INCF FSR,F
BTFSS FSR,7 ; достигнато ли е H'80'
GOTO CL
BANK0
; ИНИЦИАЛИЗАЦИЯ НА LCD
CALL LCD_INIT1
CALL INIT ; Initialize device
;=============================================================
CALL INIT_DS1307
goto v1
MOVLW D'2'
MOVWF HOUR_H
MOVLW D'2'
MOVWF HOUR_L
MOVLW D'2'
MOVWF MIN_H
MOVLW D'5'
MOVWF MIN_L
v1
CALL READ_CLOCK
call CLOCK_LCD
goto v1
;===================Initialization subroutine=====================
; This routine initializes the MSSP module
; for I2C Master mode, with a 100 kHz clock.
;=================================================================
INIT
BANK1 ; Select Bank 01
BSF TRISC, 3 ;RC3,RC4 - ВХОДОВЕ
BSF TRISC, 4 ;
CLRF SSPSTAT ; Disable SMBus inputs
BSF SSPSTAT,SMP ; Disable slew rate control
; може да се пробва и с D'99' за скорост 10kHz
MOVLW D'99' ;50 KHZ FOR FOSC = 4000 KHZ
MOVWF SSPADD ;I2C MASTER MODE, CLOCK = FOSC/(4 *(SSPADD+1))
CLRF SSPCON2 ; Clear control bits
BANK0 ; Select Bank 00
MOVLW B'00101000'
MOVWF SSPCON ; Enable SSP, select I2C Master mode
BCF PIR1,SSPIF ; Clear SSP interrupt flag
BCF PIR2,BCLIF ; Clear Bit Collision flag
RETLW 0
;===================Start bit subroutine==========================
INIT_DS1307
CLRF ADRESS
CLRF SDATA
CALL BYTEWRITE
MOVLW 7
MOVWF ADRESS
MOVLW B'10010000'
MOVWF SDATA
CALL BYTEWRITE
RETURN
;================================================
; ЗАПИС НА ВРЕМЕ В DS1307 ????????????????
;================================================
WRITE_CLOCK
CALL BSTART ; Generate Start condition
; запис на адреса на чипа
BANK0 ; Select Bank 00
MOVFW WRITE_ADDR
MOVWF DATAO ; Copy to datao for output
CALL TX
; запис на адрес 0
BANK0 ; Select Bank 00
CLRW ;ADRESS
MOVWF DATAO ; Copy to datao for output
CALL TX ; Send word address to device
;НУЛИРАНЕ СЕКУНДИ
BANK0 ; Select Bank 00
CLRW
MOVWF DATAO ; Copy to datao for output
CALL TX ; Send data byte to device
;ЗАПИС МИНУТИ
BANK0
SWAPF MIN_H,W ;ПАКЕТИРА МИН
ADDWF MIN_L,W
MOVWF DATAO
CALL TX
; ЧАСОВЕ
BANK0
SWAPF HOUR_H,W ;ПАКЕТИРА ЧАСА
ADDWF HOUR_L,W
MOVWF DATAO
CALL TX
CALL BSTOP ; Generate Stop condition
; CALL POLL ; Poll for write completion
RETLW 0
;================================================
; ЗАПИС НА ДАТА В DS1307
;================================================
WRITE_DATA
CALL BSTART ; Generate Start condition
; запис на адреса на чипа
BANK0 ; Select Bank 00
MOVFW WRITE_ADDR
MOVWF DATAO ; Copy to datao for output
CALL TX
; запис на адрес 0
BANK0 ; Select Bank 00
MOVLW H'4' ;ADRESS
MOVWF DATAO ; Copy to datao for output
CALL TX ; Send word address to device
;ЗАПИС ДНИ
BANK0
SWAPF DAY_H,W ;ПАКЕТИРА ДЕНЯ
ADDWF DAY_L,W
MOVWF DATAO ; Copy to datao for output
CALL TX ; Send word address to device
;ЗАПИС МЕСЕЦИ
BANK0
SWAPF MONTH_H,W ;ПАКЕТИРА МЕСЕЦ
ADDWF MONTH_L,W
MOVWF DATAO ; Copy to datao for output
CALL TX ; Send word address to device
;ЗАПИС ГОДИНИ
SWAPF YEAR_H,W ;ПАКЕТИРА ГОДИНА
ADDWF YEAR_L,W
MOVWF DATAO ; Copy to datao for output
CALL TX ; Send word address to device
CALL BSTOP ; Generate Stop condition
RETLW 0
;================================================
; ПОДПРОГРАМА ЗА ЧЕТЕНЕ НА ВРЕМЕ ОТ DS1307
;================================================
READ_CLOCK
CALL BSTART ; Generate Start condition
; запис на адреса на чипа
BANK0 ; Select Bank 00
MOVFW WRITE_ADDR
MOVWF DATAO ; Copy to datao for output
CALL TX
; запис на адрес 0
BANK0 ; Select Bank 00
CLRW ;ADRESS
MOVWF DATAO ; Copy to datao for output
CALL TX ; Send word address to device
;*************************
call BRESTART
; запис на адреса на чипа
BANK0 ; Select Bank 00
MOVFW READ_ADDR
MOVWF DATAO ; Copy to datao for output
CALL TX
;ЧЕТЕ СЕКУНДИ
BANK1 ; Select Bank 01
BCF SSPCON2,ACKDT ; Select to send ACK bit
CALL RX ; Input data from device
MOVFW DATAI
ANDLW B'00001111'
MOVWF SEC_L
SWAPF DATAI,W
ANDLW B'00001111'
MOVWF SEC_H
;ЧЕТЕ МИНУТИ
BANK1 ; Select Bank 01
BCF SSPCON2,ACKDT ; Select to send ACK bit
CALL RX ; Input data from device
MOVFW DATAI
ANDLW B'00001111'
MOVWF MIN_L
SWAPF DATAI,W
ANDLW B'00001111'
MOVWF MIN_H
;ЧЕТЕ ЧАСОВЕ
BANK1 ; Select Bank 01
BCF SSPCON2,ACKDT ; Select to send ACK bit
CALL RX ; Input data from device
MOVFW DATAI
ANDLW B'00001111'
MOVWF HOUR_L
SWAPF DATAI,W
ANDLW B'00001111'
MOVWF HOUR_H
CALL BSTOP ; Generate stop bit
RETLW 0
;================================================
; ПОДПРОГРАМА ЗА ЧЕТЕНЕ НА ДАТА ОТ DS1307
;================================================
READ_DATA
CALL BSTART ; Generate Start condition
; запис на адреса на чипа
BANK0 ; Select Bank 00
MOVFW WRITE_ADDR
MOVWF DATAO ; Copy to datao for output
CALL TX
; запис на адрес 0
BANK0 ; Select Bank 00
MOVLW H'4' ;ADRESS
MOVWF DATAO ; Copy to datao for output
CALL TX ; Send word address to device
;*************************
CALL BSTART ; Generate Start condition
; запис на адреса на чипа
BANK0 ; Select Bank 00
MOVFW READ_ADDR
MOVWF DATAO ; Copy to datao for output
CALL TX
;ЧЕТЕ ДЕН
BANK1 ; Select Bank 01
BCF SSPCON2,ACKDT ; Select to send ACK bit
CALL RX ; Input data from device
MOVFW DATAI
ANDLW B'00001111'
MOVWF DAY_L
SWAPF DATAI,W
ANDLW B'00001111'
MOVWF DAY_H
;ЧЕТЕ МЕСЕЦ
BANK1 ; Select Bank 01
BCF SSPCON2,ACKDT ; Select to send ACK bit
CALL RX ; Input data from device
MOVFW DATAI
ANDLW B'00001111'
MOVWF MONTH_L
SWAPF DATAI,W
ANDLW B'00001111'
MOVWF MONTH_H
;ЧЕТЕ ГОДИНА
BANK1 ; Select Bank 01
BCF SSPCON2,ACKDT ; Select to send ACK bit
CALL RX ; Input data from device
MOVFW DATAI
ANDLW B'00001111'
MOVWF YEAR_L
SWAPF DATAI,W
ANDLW B'00001111'
MOVWF YEAR_H
CALL BSTOP ; Generate stop bit
RETLW 0
;===================Start bit subroutine==========================
; This routine generates a Start condition
; (high-to-low transition of SDA while SCL
; is still high.
;=================================================================
BSTART
BANK0 ; Select Bank 00
BCF PIR1,SSPIF ; Clear SSP interrupt flag
BANK1 ; Select Bank 01
BSF SSPCON2,SEN ; Generate Start condition
BANK0 ; Select Bank 00
BSTART_WAIT
BTFSS PIR1,SSPIF ; Check if operation completed
GOTO BSTART_WAIT ; If not, keep checking
RETLW 0
;===================Restart bit subroutine==========================
; This routine generates a Repeated Start
; condition (high-to-low transition of SDA
; while SCL is still high.
;=================================================================
BRESTART
BANK0 ; Select Bank 00
BCF PIR1,SSPIF ; Clear SSP interrupt flag
BANK1 ; Select Bank 01
BSF SSPCON2,RSEN ; Generate Restart condition
BANK0 ; Select Bank 00
BRESTART_WAIT
BTFSS PIR1,SSPIF ; Check if operation completed
GOTO BRESTART_WAIT ; If not, keep checking
RETLW 0
;===================Stop bit subroutine===========================
; This routine generates a Stop condition
; (low-to-high transition of SDA while SCL
; is still high.
;=================================================================
BSTOP
BANK0
BCF PIR1,SSPIF ; Clear SSP interrupt flag
BANK1 ; Select Bank 01
BSF SSPCON2,PEN ; Generate Stop condition
BANK0
BSTOP_WAIT
BTFSS PIR1,SSPIF ; Check if operation completed
GOTO BSTOP_WAIT ; If not, keep checking
RETLW 0
;===================Data transmit subroutine======================
; This routine transmits the byte of data
; stored in 'datao' to the serial EEPROM
; device. Instructions are also in place
; to check for an ACK bit, if desired.
; Just replace the 'goto' instruction,
; or create an 'ackfailed' label, to provide
; the functionality.
;=================================================================
TX
BANK0
BCF PIR1,SSPIF ; Clear SSP interrupt flag
MOVF DATAO,W ; Copy datao to WREG
MOVWF SSPBUF ; Write byte out to device
TX_WAIT
BTFSS PIR1,SSPIF ; Check if operation completed
GOTO TX_WAIT ; If not, keep checking
;=================
; BSF STATUS,RP0 ; Select Bank 01
; BTFSC SSPCON2,ACKSTAT ; Check if ACK bit was received
; GOTO ACKFAILED ; This executes if no ACK received
;=================
RETLW 0
;===================Data receive subroutine=======================
; This routine reads in one byte of data from
; the serial EEPROM device, and stores it in
; 'datai'. It then responds with either an
; ACK or a NO ACK bit, depending on the value
; of 'ACKDT' in 'SSPCON2'.
;=================================================================
RX
BANK0 ; Select Bank 00
BCF PIR1,SSPIF ; Clear SSP interrupt flag
BANK1 ; Select Bank 01
BSF SSPCON2,RCEN ; Initiate reception of byte
BANK0 ; Select Bank 00
RX_WAIT
BTFSS PIR1,SSPIF ; Check if operation completed
GOTO RX_WAIT ; If not, keep checking
MOVF SSPBUF,W ; Copy byte to WREG
MOVWF DATAI ; Copy WREG to datai
BCF PIR1,SSPIF ; Clear SSP interrupt flag
BANK1 ; Select Bank 01
BSF SSPCON2,ACKEN ; Generate ACK/NO ACK bit
BANK0 ; Select Bank 00
RX_WAIT2
BTFSS PIR1,SSPIF ; Check if operation completed
GOTO RX_WAIT2 ; If not, keep checking
RETLW 0
;===================Byte write test subroutine====================
; This routine tests the byte write feature
; of the serial EEPROM device. It will write
; 1 byte of data to the device at address 0x5AA5.
;=================================================================
BYTEWRITE
CALL BSTART ; Generate Start condition
BANK0 ; Select Bank 00
MOVFW WRITE_ADDR
MOVWF DATAO ; Copy to datao for output
CALL TX
BANK0 ; Select Bank 00
MOVFW ADRESS
MOVWF DATAO ; Copy to datao for output
CALL TX ; Send word address to device
BANK0 ; Select Bank 00
MOVFW SDATA
MOVWF DATAO ; Copy to datao for output
CALL TX ; Send data byte to device
CALL BSTOP ; Generate Stop condition
CALL POLL ; Poll for write completion
RETLW 0
;===================Byte read test subroutine=====================
; This routine tests the byte read feature
; of the serial EEPROM device. It will read
; 1 byte of data at address 0x5AA5 from the device.
;=================================================================
BYTEREAD
CALL BSTART ; Generate Start condition
BANK0 ; Select Bank 00
MOVFW WRITE_ADDR
MOVWF DATAO ; Copy to datao for output
CALL TX ; Send high byte to device
BANK0 ; Select Bank 00
MOVFW ADRESS
MOVWF DATAO ; Copy to datao for output
CALL TX ; Send word address to device
CALL BRESTART ; Generate Restart condition
BANK0 ; Select Bank 00
MOVFW READ_ADDR
MOVWF DATAO ; Copy to datao for output
CALL TX ; Send control byte to device
BANK1 ; Select Bank 01
BSF SSPCON2,ACKDT ; Select to send NO ACK bit
CALL RX ; Read data byte from device
CALL BSTOP ; Generate Stop condition
RETLW 0
;===================Acknowledge Polling subroutine================
; This subroutine polls the EEPROM device
; for an ACK bit, which indicates that the
; internal write cycle has completed. Code
; is in place for a timeout routine, just
; uncomment the 'goto TimedOut' line, and
; provide a 'TimedOut' label.
;=================================================================
POLL
BANK0 ; Select Bank 00
MOVLW .40
MOVWF POLLCNT ; Set max polling times to 40
POLLING
CALL BRESTART ; Generate start bit
BANK0 ; Select Bank 00
MOVLW WRITE_ADDR ; Now send the control byte
MOVWF DATAO ; Copy control byte to buffer
CALL TX ; Output control byte to device
BANK1 ; Select Bank 01
BTFSS SSPCON2,ACKSTAT ; Was the ACK bit low?
GOTO EXITPOLL ; If yes, stop polling
; If no, check if polled 40 times
BANK0 ; Select Bank 00
DECFSZ POLLCNT,F ; Is poll counter down to zero?
GOTO POLLING ; If no, poll again
; GOTO TIMEDOUT ; If yes, part didn't respond
; in time, so take action
EXITPOLL
CALL BSTOP ; Generate stop bit
RETLW 0
;================================================================
;===========================================================
END
