AT83C5135 Atmel Corporation, AT83C5135 Datasheet - Page 59

• Manufacturer Part Number: AT83C5135
• Manufacturer: Atmel Corporation

Specifications of AT83C5135

• Max. Operating Frequency: 32 MHz
• Cpu: 8051-12C
• Max I/o Pins: 34
• Usb Transceiver: 1
• Usb Speed: Full Speed
• Usb Interface: Device
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Sram (kbytes): 1.25
• Eeprom (bytes): 512
• Operating Voltage (vcc): 2.7 to 3.6
• Timers: 4
• Mask Rom (kbytes): 16
• Watchdog: Yes

15. Dual Data Pointer Register
Figure 15-1. Use of Dual Pointer
7683C–USB–11/07
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 external 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 15-1) that allows the program code to switch
between them (see Figure 15-1).
Table 15-1.
Reset Value = xxxx x0x0b
Not bit addressable
a. Bit 2 stuck at 0; this allows to use INC AUXR1 to toggle DPS without changing GF3.
ASSEMBLY LANGUAGE
Number
Bit
7
6
5
4
3
2
1
0
7
-
DPS
0
Mnemonic
AUXR1 Register
AUXR1- Auxiliary Register 1(0A2h)
GF3
DPS
Bit
0
-
-
-
-
-
6
-
DPH(83H) DPL(82H)
Description
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.
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.
This bit is a general-purpose user flag.
Always cleared.
Reserved
The value read from this bit is indeterminate. Do not set this bit.
Data Pointer Selection
Cleared to select DPTR0.
Set to select DPTR1.
DPTR1
5
-
DPTR0
4
-
GF3
3
External Data Memory
AT83C5134/35/36
2
0
1
-
DPS
0
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