AT89C51RC2 Atmel Corporation, AT89C51RC2 Datasheet - Page 20

• Manufacturer Part Number: AT89C51RC2
• Manufacturer: Atmel Corporation

Specifications of AT89C51RC2

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

Dual Data Pointer
Register (DPTR)
Figure 7. Use of Dual Pointer
20
AT89C51RB2/RC2
7
AUXR1(A2H)
DPS
0
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 17) that allows the program
code to switch between them (see Figure 7).
DPH(83H) DPL(82H)
DPTR1
DPTR0
External Data Memory
4180E–8051–10/06