AT89S51-24PC Atmel, AT89S51-24PC Datasheet - Page 8

• Manufacturer Part Number: AT89S51-24PC
• Description: IC 8051 MCU 4K FLASH 40-DIP
• Manufacturer: Atmel
• Series: 89Sr

Specifications of AT89S51-24PC

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 24MHz
• Connectivity: UART/USART
• Peripherals: WDT
• Number Of I /o: 32
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -

8
AT89S51
Table 5-2.
Dual Data Pointer Registers: To facilitate accessing both internal and external data memory,
two banks of 16-bit Data Pointer Registers are provided: DP0 at SFR address locations 82H-
83H and DP1 at 84H-85H. Bit DPS = 0 in SFR AUXR1 selects DP0 and DPS = 1 selects DP1.
The user should ALWAYS initialize the DPS bit to the appropriate value before accessing the
respective Data Pointer Register.
Power Off Flag: The Power Off Flag (POF) is located at bit 4 (PCON.4) in the PCON SFR. POF
is set to “1” during power up. It can be set and rest under software control and is not affected by
reset.
AUXR
Bit
–
DISALE
DISRTO
WDIDLE
WDIDLE
0
1
Not Bit Addressable
Reserved for future expansion
Disable/Enable ALE
DISALE
Operating Mode
0
1
Disable/Enable Reset-out
DISRTO
0
1
Disable/Enable WDT in IDLE mode
AUXR: Auxiliary Register
WDT continues to count in IDLE mode
WDT halts counting in IDLE mode
–
7
Address = 8EH
ALE is emitted at a constant rate of 1/6 the oscillator frequency
ALE is active only during a MOVX or MOVC instruction
Reset pin is driven High after WDT times out
Reset pin is input only
–
6
–
5
WDIDLE
4
DISRTO
3
–
2
Reset Value = XXX00XX0B
–
1
DISALE
2487D–MICRO–6/08
0