AT89C51RB2-RLTCM ATMEL [ATMEL Corporation], AT89C51RB2-RLTCM Datasheet - Page 2

• Manufacturer Part Number: AT89C51RB2-RLTCM
• Description: 8-bit Microcontroller with 16K/ 32K Bytes Flash
• Manufacturer: ATMEL [ATMEL Corporation]

Block Diagram
Figure 1. Block Diagram
Notes:
2
1. Alternate function of Port 1.
2. Alternate function of Port 3.
AT89C51RB2/RC2
ALE/
XTAL1
XTAL2
PSEN
PROG
WR
EA
RD
(2)
(2)
CPU
In addition, the AT89C51RB2/RC2 has a Programmable Counter Array, an XRAM of
1024 Bytes, a Hardware Watchdog Timer, a Keyboard Interface, an SPI Interface, a
more versatile serial channel that facilitates multiprocessor communication (EUART)
and a speed improvement mechanism (X2 mode).
The Pinout is the standard 40/44 pins of the C52.
The fully static design reduces system power consumption of the AT89C51RB2/RC2 by
allowing it to bring the clock frequency down to any value, even DC, without loss of data.
The AT89C51RB2/RC2 has 2 software-selectable modes of reduced activity and 8-bit
clock prescaler for further reduction in power consumption. In Idle mode, the CPU is fro-
zen while the peripherals and the interrupt system are still operating. In power-down
mode, the RAM is saved and all other functions are inoperative.
The added features of the AT89C51RB2/RC2 make it more powerful for applications
that need pulse width modulation, high speed I/O and counting capabilities such as
alarms, motor control, corded phones, and smart card readers.
Table 1. Memory Size
AT89C51RB2
AT89C51RC2
Part Number
(2) (2)
(2)
Timer 0
Timer 1
EUART
BRG
(2)
+
CORE
C51
(2) (2)
256x8
RAM
Ctrl
INT
IB-bus
Flash (Bytes)
Parallel I/O Ports & Ext. Bus
32Kx8 or
Port 0Port 1 Port 2 Port 3
16Kx8
Flash
16K
32K
XRAM
1Kx8
XRAM (Bytes)
Boot
2Kx8
ROM
1024
1024
(1)
PCA
Watch
Dog
(1)
(1)
Board
Key
Timer2
TOTAL RAM
(1)
(1) (1) (1) (1)
(Bytes)
1280
1280
SPI
4180B–8051–04/03
I/O
32
32