T89C51RD2-3CWC-L datasheet(48/86 Pages) ATMEL

48 / 86 page

Rev. F - 15 February, 2001

T89C51RD2

Example : .....

; DPTR = EEPROM data pointer, A = Data to write

Wait :

MOV

A,EECON

ANL

A,#01h

JNZ

Wait

MOV

EETIM,#3Ch

; 12MHz*5 = 3Ch

MOV

EECON,#02h

; EEE=1 EEPROM mapped

MOVX @DPTR,A

; Write data to EEPROM

MOV

EECON,#50h or 52h ; Write Sequence

MOV

EECON,#A0h or A2h

....

7.4. Read Data

The following procedure is used to read the data store in the EEPROM memory:

• Map the program space (Set bit EEE of EECON register)

• Load DPTR with the address to read

• Execute a MOVX A, @DPTR

Example :

...

; DPTR = EEPROM data pointer

MOV EECON,#02h

; EEE=1 EEPROM mapped

MOVX A,@DPTR

; Read data from EEPROM

...

; A = Data

7.5. Registers

Table 25. EECON Register

EECON (S:0D2h)

EEPROM Control Register

Reset Value= XXXX XX00b

76543210

EEPL3

EEPL2

EEPL1

EEPL0

EEE

EEBUSY

Bit Number

Bit Mnemonic

Description

7-4

EEPL3-0

Programming Launch command bits

Write 5Xh followed by AXh to EECON to launch the programming.

Not implemented, reserved for future use.a

User software should not write 1s to reserved bits. These bits may be used in future 8051 family products to invoke new features. In

that case, the reset or inactive value of the new bit will be 0, and its active value will be 1. The value read from a reserved bit is

indeterminate.

Not implemented, reserved for future use.b

User software should not write 1s to reserved bits. These bits may be used in future 8051 family products to invoke new features. In

that case, the reset or inactive value of the new bit will be 0, and its active value will be 1. The value read from a reserved bit is

indeterminate.

EEE

Enable EEPROM Space bit

Set to map the EEPROM space during MOVX instructions (Write in the column latches)

Clear to map the data space during MOVX.

EEBUSY

Programming Busy flag

Set by hardware when programming is in progress.

Cleared by hardware when programming is done.

Can not be set or cleared by software.

T89C51RD2-3CWC-L Datasheet(PDF) 48 Page - ATMEL Corporation

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