PIC單片機的讀寫93XCXX程序

?TITLE??????? "R/W EEPROM"
LIST? P = 16C54
;Serial Eprom interface to PIC16C5X.
;REV 2.0??????? 8/26/92.
;
;Define Equates:
;??????
?PIC54?? EQU???? 1FFH
;
PAGE
;
?ORG???? 0
START
?goto??? main??????????? ;run test program
;
PAGE
;
TRUE??? EQU???? 1
FALSE?? EQU???? 0
S93C46? EQU???? FALSE
S93LC46 EQU???? FALSE
S93C56? EQU???? FALSE
S93LC56 EQU???? FALSE
S93C66? EQU???? TRUE
S93LC66 EQU???? FALSE
wire3?? equ???? TRUE
org8??? EQU???? FALSE
;
IF????? S93LC46
?IF????? org8
?LC468?? EQU???? TRUE
?XC46??? EQU???? FALSE
?H16???? EQU???? FALSE
?H8????? EQU???? FALSE
?ELSE
?LC468?? EQU???? FALSE
?XC46??? EQU???? TRUE
?H16???? EQU???? FALSE
?H8????? EQU???? FALSE
?ENDIF
ELSE
ENDIF
IF????? S93C46
?LC468?? EQU???? FALSE
?XC46??? EQU???? TRUE
?H16???? EQU???? FALSE
?H8????? EQU???? FALSE
ENDIF
IF????? S93C56 + S93C66 + S93LC56 + S93LC66
?IF????? org8
?H8????? EQU???? TRUE
?H16???? EQU???? FALSE
?LC468?? EQU???? FALSE
?XC46??? EQU???? FALSE
?ELSE
?H16???? EQU???? TRUE
?H8????? EQU???? FALSE
?LC468?? EQU???? FALSE
?XC46??? EQU???? FALSE
?ENDIF
ELSE
ENDIF

?

;********************************************************************
;*????????????????????? Register Assignments??????????????????????? *
;********************************************************************

indir?? equ???? 0?????? ;Use this register as source/destination
?? ;for indirect addressing.
pc????? equ???? 2?????? ;PIC Program Counter.
status? equ???? 3?????? ;PIC Status Register.
fsr???? equ???? 4?????? ;File Select Register.
serial? equ???? 5?????? ;Port used for 93CX6 control.
?? ;The following four registers must be
?? ;located consecutively in memory.
cmd???? equ???? 1a????? ;This register contains the 4 bit
?? ;command op code for 93CX6 as follows:
?? ;bit 7 msb of command op code
?? ;bit 6 next bit of op code
?? ;bit 5 next bit of op code
?? ;bit 4 lsb of op code
?? ;bit 3 A8 of address in case of
?? ;56/66 in 8 bit mode.
addr??? equ???? 1b????? ;memory address of lower 7/8 bits
highb?? equ???? 1c????? ;Used in read/write routines to store the
?? ;upper byte of a 16 bit data word,
?? ;or the data in a 8 bit data word
lowb??? equ???? 1d????? ;Used in read/write routines to store the
?? ;lower byte of a 16 bit data word,
?? ;or not used in 8 bit data word.

cnthi?? equ???? 1e????? ;Used as the upper byte of a sixteen bit
?? ;loop counter in RDYCHK routine.
cnt???? equ???? 1f????? ;Used as the lower byte of a sixteen bit
?? ;loop counter in RDYCHK routine, and
?? ;elswhere as an eight bit counter.
temp_cmd equ??? 1e????? ;doubles as a temp register for cmd???????
temp_addr equ?? 1f????? ;doubles as a temp register for addr

;********************************************************************
;*????????????????????? Bit Assignments???????????????????????????? *
;********************************************************************

carry?? equ???? 0?????????????? ;Carry Flag of Status Register.
zflag?? equ???? 2?????????????? ;Zero Flag of Status Register.

cs????? equ???? 2?????????????? ;Port pin tied to CS on 93CX6.
din???? equ???? 1?????????????? ;Port pin tied to DI on 93CX6.
dout??? equ???? 1?????????????? ;Port pin tied to DO on 93CX6.
clock?? equ???? 3?????????????? ;Port pin tied to CLK on 93CX6.

;********************************************************************
;*????????????????????? General Assignments???????????????????????? *
;********************************************************************

no_err? equ???? 0??????????????
error?? equ???? 1??????????????
tries?? equ???? 20????? ;After issuing a WRITE, ERASE, ERAL, or WRAL
?? ;command, the approximate number of machine
?? ;cycles X 256 to wait for the RDY status.
?? ;This value must be adjusted for operating
?? ;frequencies other than 4 MHz.

read??? equ???? b'10000000'???? ;read command op code
write?? equ???? b'01000000'???? ;write command op code
erase?? equ???? b'11000000'???? ;erase command op code
ewen??? equ???? b'00110000'???? ;erase enable command op code
ewds??? equ???? b'00000000'???? ;erase disable command op code
eral??? equ???? b'00100000'???? ;erase all command op code
wral??? equ???? b'00010000'???? ;write all command op code

;********************************************************************
;*????????????????????? Macro Definitions?????????????????????????? *
;********************************************************************

sel???? MACRO?????????????????? ;Selects the 93CX6 device.
?bsf???? serial,cs?????? ;Chip Select (CS) = '1' to select
?ENDM??????????????????? ;the device???????????????

dsel??? MACRO?????????????????? ;De-select the 93CX6 device.
?bcf???? serial,cs?????? ;Chip Select (CS) = '0' to de-select
??? ;the device.
?ENDM

strtbt? MACRO?????????????????? ;Issue the Start Bit to the 93CX6.
?bsf???? serial,din????? ;Start Bit = '1'.
?clkit?????????????????? ;Clock it out.
?ENDM

clkit?? MACRO?????????????????? ;Clocks a serial data bit into or out
??? ;of the 93CX6 device.
?bsf???? serial,clock??? ;Clock (CLK) = '1'.

?nop???????????? ;Adjust the number of nop instructions
?? ;between the assertion and de-assertion of
?? ;CLK in proportion to the PIC operating
?? ;frequency.? Refer to the 93CX6 data for the
?? ;minimum CLK period.
???
?bcf???? serial,clock??? ;Clock (CLK) = '0'.
?ENDM
;
PAGE
;********************************************************************
;*????????????????????? DOUTx?????????????????????????????????????? *
;********************************************************************
;doutxx, outputs up to 11 bits of op code/data, depending on whether
;a 46/56/66 serial eeprom is being used. The number of bits over 8 are
;saved in the cmd register and the rest in the addr register. Before
;calling this routine the cmd and the addr registers should be loaded
;as follows:
;cmd reg.bits 7|6|5|4|3|2|1|0
;--------------|-|-|-|-|-|-|-|
;???????????? X|X|X|X|X|X|X|Y| --> not used
;???????????? X|X|X|X|X|X|Y|X| --> mot used
;???????????? X|X|X|X|X|Y|X|X| --> not used
;???????????? X|X|X|X|Y|X|X|X| --> 9th bit of address if necessary
;???????????? X|X|X|Y|X|X|X|X| --> lsb of command op code
;???????????? X|X|Y|X|X|X|X|X| --> 3rd bit of command op code
;???????????? X|Y|X|X|X|X|X|X| --> 2nd bit of command op code
;???????????? Y|X|X|X|X|X|X|X| --> msb of command op code
;
;addr reg. 6/7/8 bits of address if necessary.

IF????? H8
dout11
?bcf???? serial,din
?rlf???? indir?????????? ;rotate thru carry
?btfsc?? status,carry??? ;set????????
?bsf???? serial,din????? ;yes, set output to 1
?clkit?????????????????? ;clk data
ENDIF
IF????? H16+H8
dout10
?rlf???? indir?????????? ;rotate thru carry
?bcf???? serial,din????? ;set output to 0
?btfsc?? status,carry??? ;set?
?bsf???? serial,din????? ;else set output to 1
?clkit?????????????????? ;clk data
ENDIF
IF????? H8+H16+LC468
dout9
?rlf???? indir?????????? ;rotate thru carry
?bcf???? serial,din????? ;set output to 0
?btfsc?? status,carry??? ;set?
?bsf???? serial,din????? ;else set output to 1
?clkit?????????????????? ;clk data
?incf??? fsr???????????? ;inc pointer
ENDIF
dout8
?movlw?? 8?????????????? ;Initialize loop counter.
?movwf?? cnt????????????
;
d_o_8?? bcf???? serial,din????? ;Assume that the bit to be transfered is a
??? ;'0'.? Hence, de-assert DI.
?rlf???? indir?????????? ;Rotate the actual bit to be transferred into
??? ;the carry bit.
?btfsc?? status,carry??? ;Test the carry, if our assumption was
??? ;correct, skip the next instruction.
?bsf???? serial,din????? ;No, actual bit was a '1'.? Assert DI.
?clkit?????????????????? ;Clock the 93CX6.
?decfsz? cnt???????????? ;Repeat until cnt = 0.
?goto??? d_o_8?????????? ;Cnt still > 0.
?rlf???? indir?????????? ;Restore register to its original condition.
?bcf???? serial,din????? ;make sure din is low???????
?retlw?? no_err????????? ;Exit with good status.

;********************************************************************
;*????????????????????? DIN8??????????????????????????????????????? *
;********************************************************************
??? ;Din8 will input 8 bits of data from the
??? ;93CX6.? Before calling this routine, the FSR
??? ;must point to the register being used to
??? ;hold the incomming data.
din8???
IF????? wire3
;set up the RA1 as a input before proceeding???????
?movlw?? b'00000010'???? ;set up porta
?tris??? serial????????? ;
ENDIF
?movlw?? 8?????????????? ;Initialize loop counter.
?movwf?? cnt???????????? ;

d_i_8??
?rlf???? indir?????????? ;Make room for the incomming bit in the
??? ;destination register.
?bcf???? indir,0???????? ;Assume that the incomming bit is a '0' and
??? ;clear the LSB of the destination register.
?clkit?????????????????? ;Clock a bit in the 93CX6.
?btfsc?? serial,dout???? ;Test the incomming bit, if our assumption
??? ;was correct, skip the next instruction.
?bsf???? indir,0???????? ;No, actual bit is a '1'.? Set the LSB of the
??? ;destination register.
?decfsz? cnt???????????? ;Repeat until cnt = 0.
?goto??? d_i_8?????????? ;Cnt still > 0.
IF????? wire3
;setup RA1 back to output
?movlw?? 0?????????????? ;set RA1 as output
?tris??? serial????????? ;????? /
ENDIF
?retlw?? no_err????????? ;Exit with good status.

;********************************************************************
;*????????????????????? RDYCHK????????????????????????????????????? *
;********************************************************************
??? ;Rdychk will read the 93CX6 READY/BUSY status
??? ;and wait for RDY status within the alloted
??? ;number of processor cycles.? If RDY status
??? ;is not present after this set period, the
??? ;routine will return with an error status.

rdychk?
IF????? wire3
;set up RA1 as a input before proceeding???????
?movlw?? b'00000010'???? ;set up porta
?tris??? serial????????? ;
ENDIF
?movlw?? tries?????????? ;Initialize time-out counter.
?movwf?? cnthi?????????? ;
?clrf??? cnt???????????? ;
?dsel??????????????????? ;De-select the 93CX6.

;?????? nop???????????????????? ;NOTE:? Check the 93CX6 data sheet for
??? ;minimum CS low time.? Depending upon
??? ;processor frequency, a nop(s) may be
??? ;between the assertion and de-assertion of
??? ;Chip Select.

?sel???????????????????? ;Re-select the 93CX6.
notrdy? btfsc?? serial,dout???? ;If DO is a '0', 93CX6 has yet to completed
??? ;the last operation (still busy).
?goto??? rdynoerr??????? ;skip to no error
?decfsz? cnt???????????? ;No, not yet ready.? Decrement the LSB of our
??? ;16 bit timer and check for expiration.
?goto??? notrdy????????? ;Still some time left.? Try again.
?decfsz? cnthi?????????? ;Least significant byte expired - decrement
??? ;and check for expiration of the MSB.
?goto??? notrdy????????? ;Still some time left.? Try again.
IF????? wire3
;setup RA1 back to output
?movlw?? 0?????????????? ;set RA1 as output
?tris??? serial????????? ;????? /
ENDIF
?retlw?? error?????????? ;RDY status was not present in the alloted
??? ;time, return with error status.
rdynoerr
IF????? wire3
;setup RA1 back to output
?movlw?? 0?????????????? ;set porta as output
?tris??? serial????????? ;????? /
ENDIF
?retlw?? no_err

;********************************************************************
;*????????????????????? SEE???????????????????????????????????????? *
;********************************************************************

??? ;See will control the entire operation of a
??? ;93CX6 device.? Prior to calling the routine,
??? ;load a valid command/memory address into
??? ;location cmd, and for WRITE or WRAL
??? ;commands, load registers highb and lowb with
??? ;16 bits of write data.? Upon exit, the W
??? ;register will contain the completion status.
??? ;Only 93CX6 instructions which require a
??? ;status check can return with an error as the
??? ;completion status.? The values that denote
??? ;the completion status are defined as
??? ;variables 'error' and 'no_err' in the
??? ;general assignments section.

see????
?movf??? cmd,w?????????? ;save cmd
?movwf?? temp_cmd
?movf??? addr,w????????? ;save addr
?movwf?? temp_addr?????? ;
?movlw?? cmd???????????? ;Load W with the location of the cmd
??? ;register.
?movwf?? fsr???????????? ;Transfer that information into the File
??? ;Select Register.? The fsr now points to
??? ;location cmd.
?sel???????????????????? ;Select the 93CX6.
?strtbt????????????????? ;Send a start bit.
;
?btfsc?? cmd,7?????????? ;bit 7 = 0?
IF????? XC46
?goto??? sca8??????????? ;xfer 8 bit cmd/adr
ENDIF
IF????? LC468
?goto??? sca9??????????? ;xfer 9 bit cmd/adr
ENDIF
IF????? H16????
?goto??? sca10?????????? ;xfer 10 bit cmd/adr
ENDIF
IF????? H8
?goto??? sca11?????????? ;xfer 11 bit cmd/adr
ENDIF

;??????? goto??? set_cmd_addr??? ;no then set cmd/addr
?btfss?? cmd,6?????????? ;bit 6 = 0 ???
IF????? XC46
?goto??? sc8???????????? ;xfer 8 bit cmd/adr
ENDIF
IF????? LC468
?goto??? sc9???????????? ;xfer 9 bit cmd/adr
ENDIF??
IF????? H16????
?goto??? sc10??????????? ;xfer 10 bit cmd/adr
ENDIF
IF????? H8
?goto??? sc11??????????? ;xfer 11 bit cmd/adr
ENDIF
;??????? goto??? set_cmd???????? ;yes then set cmd
IF????? XC46
?goto??? sca8??????????? ;xfer 8 bit cmd/adr
ENDIF
IF????? LC468
?goto??? sca9??????????? ;xfer 9 bit cmd/adr
ENDIF
IF????? H16????
?goto??? sca10?????????? ;xfer 10 bit cmd/adr
ENDIF
IF????? H8
?goto??? sca11?????????? ;xfer 11 bit cmd/adr
ENDIF

;??????? goto??? set_cmd_addr??? ;else set cmd/addr
see1
?movf??? temp_cmd,w????? ;retore cmd????
?movwf?? cmd???????????? ;?????? /
?movf??? temp_addr,w???? ;restore addr
?movwf?? addr??????????? ;?????? /
?btfsc?? cmd,6?????????? ;Check for a WRITE or ERASE command.
?goto??? see2??????????? ;Yes, parse the command further.
?btfsc?? cmd,7?????????? ;Check for a READ command.
?goto??? read_?????????? ;Yes, process READ command.
?btfsc?? cmd,5?????????? ;Check for a EWEN or ERAL command.
?goto??? see3??????????? ;Yes, parse the command further.
?btfsc?? cmd,4?????????? ;Check for a WRAL command.
?goto??? write_????????? ;Yes, process WRITE/WRAL command.

exit_?? dsel??????????????????? ;No further processing required; 93CX6
??? ;command completed.
;
?retlw?? no_err????????? ;Return with good completion status.

see2??? btfss?? cmd,7?????????? ;Check for a ERASE command.
?goto??? write_????????? ;No, process WRITE command.
exit2_? call??? rdychk????????? ;ERASE command requires a status check.
?dsel??????????????????? ;De-select the 93CX6.
?addwf?? pc????????????? ;Compute completion status from results of
??? ;status check.
?retlw?? no_err????????? ;Return with good completion status.
?retlw?? error?????????? ;Return with bad completion status.

see3??? btfsc?? cmd,4?????????? ;Check for a EWEN command.
?goto??? exit_?????????? ;Yes, no further processing required, exit
??? ;now.
?goto??? exit2_????????? ;No, ERAL command which requires a status
??? ;check.

read_?? incf??? fsr???????????? ;Increment the File Select Register to point
??? ;to the register receiving the upper byte of
??? ;the incomming 93CX6 data word.
?call??? din8??????????? ;Input the upper byte.
IF????? org8
ELSE
?incf??? fsr???????????? ;Increment the File Select Register to point
??? ;to the register receiving the lower byte.
?call??? din8??????????? ;Input 8 more bits.
ENDIF
?goto??? exit_?????????? ;No further processing required, exit now.

write_? incf??? fsr???????????? ;Increment the File Select Register to point
??? ;to the upper byte of the 16 bit 93CX6 data
??? ;word to be transmitted.
?call??? dout8?????????? ;Output that byte.
IF????? org8
ELSE
?incf??? fsr??????????? ;Increment the File Select Register to point
????????? ;to the lower byte.
?call??? dout8????????? ;Output the lower byte of the 16 bit 93CX6
????????? ;data word.
ENDIF
?goto??? exit2_????????? ;Exit with a status check.

;
;
IF????? XC46
sca8
?movlw?? b'11000000'???? ;clr all but hi 2
?andwf?? cmd,w?????????? ;save in w
?iorwf?? addr??????????? ;mask in addr.
?incf??? fsr???????????? ;inc FSR
?call??? dout8?????????? ;output
?goto??? see1??????????? ;return
ENDIF
IF????? LC468
;
sca9
?bcf???? addr,7????????? ;clr hi of addr
?btfsc?? cmd,6?????????? ;xfer cmd's bit 6
?bsf???? addr,7????????? ;to addr's bit 7
?call??? dout9?????????? ;output
?goto??? see1??????????? ;return
ENDIF
IF????? H16
;
sca10??
?call??? dout10????????? ;output cmd reg
?goto??? see1??????????? ;return
ENDIF???????????????
;
IF????? H8
sca11
?bcf???? cmd,5?????????? ;xfer cmd's bit 3 to
?btfsc?? cmd,3?????????? ;cmd's bit 5
?bsf???? cmd,5?????????? ;?????? /
?call??? dout11????????? ;output
?goto??? see1??????????? ;return
;
ENDIF
;
;
;
IF????? XC46
sc8
?movf??? cmd,w?????????? ;get command
?movwf?? addr??????????? ;save in addr
?incf??? fsr???????????? ;inc pointer
?call??? dout8?????????? ;output
?goto??? see1??????????? ;return
;
ENDIF
IF????? LC468
sc9????
?rlf???? cmd,w?????????? ;rotate cmd left
?movwf?? addr??????????? ;save in addr
?call??? dout9?????????? ;xfer 9 bits
?goto??? see1??????????? ;return
ENDIF
IF????? H16
;
sc10???
?rlf???? cmd???????????? ;rotate cmd
?rlf???? cmd,w?????????? ;left twice
?movwf?? addr??????????? ;save in addr
?clrf??? cmd???????????? ;clear command
?call??? dout10????????? ;xfer 10 bits
?goto??? see1??????????? ;return
ENDIF
;
IF????? H8
sc11
?bcf???? addr,7????????? ;xfer cmd's bit 4
?btfsc?? cmd,4?????????? ;to addr's bit 7
?bsf???? addr,7????????? ;?????? /
?call??? dout11????????? ;xfer 11 bits
?goto??? see1??????????? ;return
ENDIF
;********************************************************************
;*????????????????????? Test Program??????????????????????????????? *
;********************************************************************
?main??????????????????? ;We've include a sample program to exercise
??? ;the PIC to 93C66 interface using a simple
??? ;erase, write and verify routine.
??? ;8 bit organization has been used
??? ;with a 3 wire interface.
?
?clrf??? serial????????? ;Clear the port tied to the 93C66 device.
?movlw?? b'11110000'???? ;Intialize the data direction register for
?tris??? serial????????? ;that port.
?
?movlw?? ewen??????????? ;Load W with the Erase/Write Enable command.
?movwf?? cmd???????????? ;Transfer W into cmd register.
?call??? see???????????? ;Enable the 93C66 device.

?movlw?? eral??????????? ;Load W with the Erase All command.
?movwf?? cmd???????????? ;Transfer W into cmd register.
?call??? see???????????? ;Erase the 93C66.
?xorlw?? error?????????? ;Check completion status.
?btfsc?? status, zflag?? ;Test for error condition.
?goto??? errloop???????? ;Yes, bad completion status, error-out.

??? ;Write loop:
tstptrn equ???? 0xAA??????????? ;Define the test pattern to be written.

?movlw?? write?????????? ;Load W with the Write command.
?movwf?? cmd???????????? ;Transfer W into cmd register.
?movlw?? tstptrn???????? ;Intialize the 93C66 data registers with
??? ;write data.
?movwf?? highb?????????? ;load in high byte only
??? ;since 8 bit low byte is ignored
?clrf??? addr??????????? ;start at addr 0
test1?? call??? see???????????? ;Write data word into 93C66 device.
?xorlw?? error?????????? ;Check completion status.
?btfsc?? status,zflag??? ;Test for error condition.
?goto??? errloop???????? ;Yes, bad completion status, error-out.
?incfsz? addr??????????? ;No, increment the 8 bit memory address
??? ;field.
?goto??? test1?????????? ;write another location
?btfss?? cmd,3?????????? ;see if all done
?goto??? wrt_nxt_pg????? ;no then write next page
?goto??? read_tst??????? ;read written data
wrt_nxt_pg
?bsf???? cmd,3?????????? ;set page bit
?goto??? test1?????????? ;No, write another location.

??? ;Read loop:
read_tst
?movlw?? read??????????? ;Load W with the Read command.
?movwf?? cmd???????????? ;Transfer W into cmd register.
test2?? call??? see???????????? ;Read addressed data word from 93C66 device.
?movlw?? tstptrn???????? ;Load W with the pattern written.
?subwf?? highb,w???????? ;Verify the data read against what was
??? ;written.
?btfss?? status,zflag??? ;Same?
?goto??? errloop???????? ;No, error-out.
?incfsz? addr??????????? ;Yes, both byte correct, increment the 8 bit
??? ;memory address field.
?goto??? test2?????????? ;do next byte
?btfss?? cmd,3?????????? ;check page bit
?goto??? rd_nxt_pg?????? ;no then chk next page
?goto??? allok?????????? ;all done!!!
rd_nxt_pg
?bsf???? cmd,3?????????? ;set page bit
?goto??? test2?????????? ;No, read another location.

allok?? goto??? allok?????????? ;Home safe!
;
;
errloop
?goto??? errloop
;
;
;
;KEY DEFINITIONS
;
?ORG???? PIC54
SYS_RESET
?GOTO??? START
;
?END