AT89C51RD2-RDTUM Atmel, AT89C51RD2-RDTUM Datasheet - Page 2

• Manufacturer Part Number: AT89C51RD2-RDTUM
• Description: 8-bit Microcontrollers - MCU Microcontroller
• Manufacturer: Atmel

Specifications of AT89C51RD2-RDTUM

• Product Category: 8-bit Microcontrollers - MCU
• Core: 8051
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 60 MHz
• Program Memory Size: 64 KB
• Data Ram Size: 2 KB
• On-chip Adc: No
• Operating Supply Voltage: 2.7 V to 5.5 V
• Package / Case: VQFP
• Mounting Style: SMD/SMT
• Interface Type: EUART, SPI
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Number Of Programmable I/os: 48
• Number Of Timers: 3 bit
• Program Memory Type: Flash
• Factory Pack Quantity: 800
• Supply Voltage - Max: 5.5 V
• Supply Voltage - Min: 2.7 V

6. Boot Process - Upper 2Kbytes Execution with BLJB = 0
7. Flash/EEPROM - First Read after Load Disturbed
2
MOVX @DPTR,A ;Load Column latches
NOP ; ADDED INSTRUCTION
Use the same mode for the two timers..
In case of Boot process with BLJB = 0 and BSB = 00, the User Application is executed but the program space located
in the upper 2KBytes of the 64KBytes on chip Flash memory cannot be executed. This is due to ENBOOT bit which is
set in this Bootloader flow.
Workaround
Clear ENBOOT bit at the beginning of user application software.
In the ‘In-Application Programming’ mode from the Flash, if the User software application loads the Column Latch Area
prior to calling the programming sequence in the UART Bootloader.
The ‘Read after load’ issue leads to a wrong Opcode Fetch during the column latch load sequence.
Workaround
Update of the Flash API Library. A NOP instruction has to be inserted after the load instruction.
AT89C51RD2/ED2
4257E–8051–08/07