AT89C51ID2 Atmel Corporation, AT89C51ID2 Datasheet - Page 30

• Manufacturer Part Number: AT89C51ID2
• Manufacturer: Atmel Corporation

Specifications of AT89C51ID2

• Flash (kbytes): 64 Kbytes
• Max. Operating Frequency: 60 MHz
• Cpu: 8051-12C
• Max I/o Pins: 32
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Sram (kbytes): 2
• Eeprom (bytes): 2048
• Self Program Memory: API
• Operating Voltage (vcc): 2.7 to 5.5
• Timers: 4
• Isp: UART
• Watchdog: Yes

Registers
4289C–8051–11/05
Table 24. AUXR Register
AUXR - Auxiliary Register (8Eh)
Reset Value = XX00 10’HSB. XRAM’0b
Not bit addressable
Number
Bit
7
-
7
6
5
4
3
2
1
0
Mnemonic Description
EXTRAM
XRS2
XRS1
XRS0
Bit
AO
M0
6
-
-
-
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Pulse length
Cleared to stretch MOVX control: the RD/ and the WR/ pulse length is 6 clock
periods (default).
Set to stretch MOVX control: the RD/ and the WR/ pulse length is 30 clock
periods.
XRAM Size
XRS2 XRS1XRS0XRAM size
0
0
0
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 during a MOVX or MOVC
instruction is used.
0
M0
5
0
0
1
1
0
0 256 bytes
1 512 bytes
0 768 bytes(default)
1 1024 bytes
0 1792 bytes
XRS2
4
XRS1
3
XRS0
2
AT89C51ID2
EXTRAM
1
AO
0
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