📄 pic12ce519
字号:
GOTO START ;
;^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
;--------------------------------------------------------------------
START1. NOP ; 1.
START2. NOP ; 2.
START3. NOP ; 3.
START4. NOP ; 4.
START5. NOP ; 5.
START6. CALL STEP ; 6.-7.
START1 NOP ; 1
START2 NOP ; 2
START3 NOP ; 3
START4 NOP ; 4
START5 NOP ; 5
START6 NOP ; 6
START7 NOP ; 7
START8 NOP ; 8
START9 NOP ; 9
START10 GOTO START ; 10-11
START11 NOP ; 11
START12 NOP ; 12
START13 NOP ; 13
START14 NOP ; 14
START15 NOP ; 15
START16 NOP ; 16
START17 NOP ; 17
START18 NOP ; 18
START19 NOP ; 19
START20 NOP ; 20
START21 NOP ; 21
START22 NOP ; 22
START23 GOTO START1. ; 23-24
;*******************************************************************
ORG 0200h
TITLE "PIC with EEPROM Data Memory Interface"
LIST P=12CE519
SCL EQU 0x07 ; EEPROM Clock, SCL (I/O bit 7)
SDA EQU 0x06 ; EEPROM Data, SDA (I/O bit 6)
OK EQU 1
NO EQU 0
EE_OK EQU 7 ; Bit 7 in PC_OFFSET used as OK flag for EE
PC_OFFSET EQU 0x07 ; PC offset register (low order 4 bits),
; value based on operating mode of EEPROM.
; Also, bit 7 used for EE_OK flag
COUNTER EQU 0x08 ; Bit counter for serial transfer
EEBYTE EQU 0x09 ; Byte sent to or received from
; EEPROM (control, address, or data)
EEADDR EQU 0x0A ; EEPROM Address
EEDATA EQU 0x0F ; EEPROM Data
;********************** Set up EEPROM control bytes ************************
READ_CURRENT
MOVLW B'10000100' ; PC offset for read current addr. EE_OK bit7='1'
MOVWF PC_OFFSET ; Load PC offset
GOTO INIT_READ_CONTROL
WRITE_BYTE
MOVLW B'10000000' ; PC offset for write byte. EE_OK: bit7 = '1'
GOTO INIT_WRITE_CONTROL
READ_RANDOM
MOVLW B'10000011' ; PC offset for read random. EE_OK: bit7 = '1'
INIT_WRITE_CONTROL
MOVWF PC_OFFSET ; Load PC offset register, value preset in W
MOVLW B'10100000' ; Control byte with write bit, bit 0 = '0'
START_BIT
BCF GPIO,SDA ; Start bit, SDA and SCL preset to '1'
;******* Set up output data (control, address, or data) and counter ********
PREP_TRANSFER_BYTE
MOVWF EEBYTE ; Byte to transfer to EEPROM already in W
MOVLW 8 ; Counter to transfer 8 bits
MOVWF COUNTER
;************ Clock out data (control, address, or data) byte ************
OUTPUT_BYTE
BCF GPIO,SCL ; Set clock low during data set-up
RLF EEBYTE,1 ; Rotate left, high order bit into carry bit
BCF GPIO,SDA ; Set data low, if rotated carry bit is
BTFSC STATUS,CARRY ;(SKPNC) a '1', then:
BSF GPIO,SDA ; reset data pin to a one, otherwise leave low
NOP
BSF GPIO,SCL ; clock data into EEPROM
DECFSZ COUNTER,1 ; Repeat until entire byte is sent
GOTO OUTPUT_BYTE
NOP ; Needed to meet Timing (Thigh=4000nS)
;************************** Acknowkedge Check *****************************
BCF GPIO,SCL ; Set SCL low, 0.5us < ack valid < 3us
NOP ; Needed to meet Timing (Tlow= 4700nS)
BSF GPIO,SDA
NOP ; Necessary for SCL Tlow at low voltage,
NOP ; Tlow=4700nS
BSF GPIO,SCL ; Raise SCL, EEPROM acknowledge still valid
BTFSC GPIO,SDA ; Check SDA for acknowledge (low)
BCF PC_OFFSET,EE_OK ; If SDA not low (no ack), set error flag
BCF GPIO,SCL ; Lower SCL, EEPROM release bus
BTFSS PC_OFFSET,EE_OK ; If no error continue, else stop bit
GOTO STOP_BIT
;***** Set up program counter offset, based on EEPROM operating mode *****
MOVF PC_OFFSET,0
ANDLW B'00001111'
ADDWF PC
GOTO INIT_ADDRESS ;PC offset=0, write control done, send address
GOTO INIT_WRITE_DATA ;PC offset=1, write address done, send data
GOTO STOP_BIT ;PC offset=2, write done, send stop bit
GOTO INIT_ADDRESS ;PC offset=3, write control done, send address
GOTO INIT_READ_CONTROL ;PC offset=4, send read control
GOTO READ_BIT_COUNTER ;PC offset=5, set counter and read byte
GOTO STOP_BIT ;PC offset=6, random read done, send stop
;********** Initalize EEPROM data (address, data, or control) bytes ******
INIT_ADDRESS
INCF PC_OFFSET,1 ; Increment PC offset to 2 (write) or to 4 (read)
MOVF EEADDR,W ; Put EEPROM address in W, ready to send to EEPROM
GOTO PREP_TRANSFER_BYTE
INIT_WRITE_DATA
INCF PC_OFFSET,1 ; Increment PC offset to go to STOP_BIT next
MOVF EEDATA,0 ; Put EEPROM data in W, ready to send to EEPROM
GOTO PREP_TRANSFER_BYTE
INIT_READ_CONTROL
BSF GPIO,SCL ; Raise SCL
BSF GPIO,SDA ; raise SDA
INCF PC_OFFSET,1 ; Increment PC offset to go to READ_BIT_COUNTER next
MOVLW B'10100001' ; Set up read control byte, ready to send to EEPROM
GOTO START_BIT ; bit 0 = '1' for read operation
;************************** Read EEPROM data *****************************
READ_BIT_COUNTER
BSF GPIO,SDA ; set data bit to 1 so we're not pulling bus down.
NOP
BSF GPIO,SCL
MOVLW 8 ; Set counter so 8 bits will be read into EEDATA
MOVWF COUNTER
READ_BYTE
BSF GPIO,SCL ; Raise SCL, SDA valid. SDA still input from ack
SETC ; Assume bit to be read = 1
BTFSS GPIO,SDA ; Check if SDA = 1
BCF STATUS,CARRY ;(CLRC) if SDA not = 1 then clear carry bit
RLF EEDATA,1 ; rotate carry bit (=SDA) into EEDATA;
BCF GPIO,SCL ; Lower SCL
bsf GPIO,SDA ; reset SDA
DECFSZ COUNTER,1 ; Decrement counter
GOTO READ_BYTE ; Read next bit if not finished reading byte
BSF GPIO,SCL
NOP
BCF GPIO,SCL
;****************** Generate a STOP bit and RETURN ***********************
STOP_BIT
BCF GPIO,SDA ; SDA=0, on TRIS, to prepare for transition to '1'
BSF GPIO,SCL ; SCL = 1 to prepare for STOP bit
GOTO $+1 ; equivalent 4 NOPs neccessary for I2C spec Tsu:sto = 4.7us
GOTO $+1
BSF GPIO,SDA ; Stop bit, SDA transition to '1' while SCL high
BTFSS PC_OFFSET,EE_OK ; Check for error
RETLW NO ; if error, send back NO
RETLW OK ; if no error, send back OK
;************************ End EEPROM Subroutines **************************
;XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
;XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
;XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
;XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
;XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
;XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
;XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
;XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
;
; 0111 1RRR DDDD DDDD -> register mode
;
; 0111 10AA AAAA AAAA 111K DBBB ; Bit manipulation
; verify/write^
;....................................................................
CV BSF FSR,5 ; rampage to 0x30..
;--------------------------------
MOVF BT1,0 ; 25
BTFSS BT1,7 ; >0<AAA AAAA 26
GOTO SHORTA ; short adress 27
XORWF CV17,0 ; 28
BTFSS STATUS,ZERO ; 29
GOTO CHKPROG ; 30-31
MOVF BT2,0 ; 31
XORWF CV18,0 ; 32
BTFSS STATUS,ZERO ; 33
GOTO CHKPROG ; 34
MOVLW 0x2C ; BT3 35
MOVWF FSR ; to 3. byte 36
BTFSS LADRE ; long adress enabled? 37
GOTO CHKPROG ; 38
BTFSC CONSIST ; 39
GOTO CHKPROG ; 40
; NOP ; 41
; NOP ; 42
GOTO DECOD ; 43-44
;--------------------------------
;BCAST NOP ; 32
; NOP ; 33
; NOP ; 34
; NOP ; 35
BCAST GOTO OVER1 ; 36-37
OVER BTFSC CONSIST ; 36
GOTO HOPP ; 37
;OVER1 NOP ; 38
OVER1 GOTO BCBCK ; 39-40
;--------------------------------
CHKPROG MOVF BT1,0 ;
ANDLW 11110000b ; untere 3bit ausblenden
XORLW 01110000b ; >= 120 (120=CV1 121=CV2 ...)
BTFSC STATUS,ZERO ;
GOTO PROG ; register mode (CV1-CV8)
GOTO HOPP ;
;--------------------------------
SHORTA BTFSC STATUS,ZERO ; address = 0 29
GOTO BCAST ; 30-31
BTFSS LADRE ; long Adress enabled? 31
XORWF CV1,0 ; 32
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