Freescale Semiconductor, Inc.
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*
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*
EEPROM Command SubRoutines
* These 7 subroutines execute each of the 7 commands
* that the EEPROM will respond to
*
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***
EWEN - subroutine to enable write/erase ******************************
J9356_EWEN
lda
sta
lda
sta
bset
jsr
jsr
bclr
rts
#$80
OPCODE
#$C0
ADDR
CS,PORTA
J9356_WR_OP
;load opcode
;load address
;CS line is high
;write opcode
J9356_WR_ADDR ;write address
CS,PORTA
;CS line is low
;return
***
EWDS - subroutine to disable write/erase *****************************
J9356_EWDS
lda
sta
clr
bset
jsr
jsr
bclr
rts
#$80
OPCODE
ADDR
;load opcode
;load addr
;CS line is high
;write opcode
CS,PORTA
J9356_WR_OP
J9356_WR_ADDR ;write address
CS,PORTA
;CS line is low
;return
***
WRITE - subroutine to write EEPROM ***********************************
J9356_WRITE
lda
sta
bset
jsr
jsr
jsr
bclr
bclr
jsr
rts
#$A0
OPCODE
;load opcode
CS,PORTA
J9356_WR_OP
J9356_WR_ADDR ;write address
J9356_WR_DATA ;write data
SER_OUT,PORTA
;CS line is high
;write opcode
CS,PORTA
J9356_WAIT
;CS line is low
;wait until EEPROM is ready
;return
AN1241/D
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