AT89C51RD2 Atmel Corporation, AT89C51RD2 Datasheet - Page 90

• Manufacturer Part Number: AT89C51RD2
• Manufacturer: Atmel Corporation

Specifications of AT89C51RD2

• Flash (kbytes): 64 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 32
• Spi: 1
• Uart: 1
• Sram (kbytes): 2
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART
• Watchdog: Yes

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
4235K–8051–05/08