AT80C51RD2 Atmel Corporation, AT80C51RD2 Datasheet - Page 16

• Manufacturer Part Number: AT80C51RD2
• Manufacturer: Atmel Corporation

Specifications of AT80C51RD2

• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 32
• Spi: 1
• Uart: 1
• Sram (kbytes): 1.25
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Watchdog: Yes

16
AT80C51RD2
Reset Value = XX0X 00’HSB.XRAM’0b (see
Not bit addressable
Number
Bit
3
2
1
0
Mnemonic
EXTRAM
XRS1
XRS0
Bit
AO
Description
XRAM Size
XRS1
0
0
1
1
EXTRAM bit
Cleared to access internal XRAM using MOVX @ Ri/ @ DPTR.
Set to access external memory.
Programmed by hardware after Power-up regarding Hardware Security Byte (HSB),
default setting, XRAM selected.
ALE Output bit
Cleared, ALE is emitted at a constant rate of 1/6 the oscillator frequency (or 1/3 if X2
mode is used) (default). Set, ALE is active only if a MOVX or MOVC instruction is used.
0
1
0
1
XRS0
XRAM Size
256 bytes (default)
512 bytes
768 bytes
1024 bytes
Table
8-1)
4113D–8051–01/09