at89c51rd2-smsum ATMEL Corporation, at89c51rd2-smsum Datasheet - Page 3

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

2. Block Diagram
Figure 2-1.
4235J–8051–01/08
Block Diagram
ALE/
XTALA1
XTALA2
PSEN
PROG
WR
EA
RD
(2)
(2)
CPU
(2) (2)
(2)
Timer 0
Timer 1
EUART
(2)
CORE
C51
(2) (2)
256x8
RAM
Ctrl
INT
IB-bus
(1): Alternate function of Port 1
(2): Alternate function of Port 3
Port 0 Port 1
64K x 8
Flash
Parallel I/O Ports &
External Bus
Port 2
1792 x 8
XRAM
Port 3
(1)
Port4
PCA
Port 5
(1)
(1)
Timer2
(1)
(1) (1)(1)(1)
AT89C51RD2/ED2
SPI
Keyboard
(1)
2K x 8
BOOT
ROM
Watch
-dog
Regulator
POR / PFD
(AT89C51ED2)
EEPROM*
2K x 8
3