AT89C51ID2 Atmel Corporation, AT89C51ID2 Datasheet - Page 25

• 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

Dual Data Pointer
Register DPTR
Figure 5. Use of Dual Pointer
4289C–8051–11/05
7
AUXR1(A2H)
The additional data pointer can be used to speed up code execution and reduce code
size.
The dual DPTR structure is a way by which the chip will specify the address of an exter-
nal data memory location. There are two 16-bit DPTR registers that address the external
memory, and a single bit called DPS = AUXR1.0 (see Table 23) that allows the program
code to switch between them (Refer to Figure 5).
DPS
0
DPH(83H) DPL(82H)
DPTR1
DPTR0
External Data Memory
AT89C51ID2
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