t89c51rd2-slscl ATMEL Corporation, t89c51rd2-slscl Datasheet - Page 51

• Manufacturer Part Number: t89c51rd2-slscl
• Description: 0 To 40 Mhz Flash Programmable 8-bit Microcontroller
• Manufacturer: ATMEL Corporation

Read Data
Registers
4243G–8051–05/03
The following procedure is used to read the data store in the EEPROM memory:
•
•
•
Example :
Table 32. EECON Register
EECON (S:0D2h)
EEPROM Control Register
1.
2.
Reset Value = XXXX XX00b
Bit Number
EEPL3
Map the program space (Set bit EEE of EECON register)
Load DPTR with the address to read
Execute a MOVX A, @DPTR
7-4
7
3
2
1
0
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.
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.
...
Mnemonic
EEPL2
EEPL3-0
EEBUSY
6
EEE
Bit
-
-
Description
Programming Launch command bits
Write 5Xh followed by AXh to EECON to launch the programming.
Not implemented, reserved for future use.
Not implemented, reserved for future use.
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.
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.
EEPL1
5
MOV
MOVX
...
; DPTR = EEPROM data pointer
EECON,#02h
A,@DPTR
EEPL0
4
3
-
; EEE=1 EEPROM mapped
; Read data from EEPROM
(1)
(2)
2
-
T89C51RD2
EEE
1
; A = Data
EEBUSY
0
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