at89c51rd2-smsum ATMEL Corporation, at89c51rd2-smsum Datasheet - Page 90

• Manufacturer Part Number: at89c51rd2-smsum
• Description: 8-bit Flash Microcontroller
• Manufacturer: ATMEL Corporation

23.2
90
Read Data
AT89C51RD2/ED2
Figure 23-1. Recommended EEPROM Data Write Sequence
The following procedure is used to read the data stored in the EEPROM memory:
• Check EEBUSY flag
• If the user application interrupts routines use XRAM memory space: Save and disable
• Load DPTR with the address to read
• Set bit EEE of EECON register
• Execute a MOVX A, @DPTR
• Clear bit EEE of EECON register
• Restore interrupts.
interrupts.
Exec: MOVX @DPTR, A
EECON = 00h (EEE=0)
EEPROM Data Write
EEPROM Data Mapping
EECON = 02h (EEE=1)
EEPROM Mapping
Save & Disable IT
DPTR= Address
ACC= Data
Last Byte
Data Write
Sequence
to Load?
Cleared?
Restore IT
EEBusy
EA= 0
4235J–8051–01/08