AT89LP6440 Atmel Corporation, AT89LP6440 Datasheet - Page 27

• Manufacturer Part Number: AT89LP6440
• Manufacturer: Atmel Corporation

Specifications of AT89LP6440

• Flash (kbytes): 64 Kbytes
• Max. Operating Frequency: 20 MHz
• Cpu: 8051-1C
• Max I/o Pins: 38
• Spi: 1
• Twi (i2c): 1
• Uart: 1
• Adc Channels: 8
• Adc Resolution (bits): 10
• Adc Speed (ksps): 153.8
• Sram (kbytes): 4.25
• Eeprom (bytes): 8192
• Self Program Memory: IAP
• Operating Voltage (vcc): 2.4 to 3.6
• Timers: 3
• Isp: SPI/OCD
• Watchdog: Yes

5.2.1
3706C–MICRO–2/11
Data Pointer Update
Table 5-2.
The Dual Data Pointers on the AT89LP3240/6440 include two features that control how the data
pointers are updated. The data pointer decrement bits, DPD1 and DPD0 in DPCF, configure the
INC DPTR instruction to act as DEC DPTR. The resulting operation will depend on DPS as
shown in
Table 5-3.
The data pointer update bits, DPU1 and DPU0, allow MOVX @DPTR and MOVC @DPTR
instructions to update the selected data pointer automatically in a post-increment or post-decre-
ment fashion. The direction of update depends on the DPD1 and DPD0 bits as shown in
5-4.
Table 5-4.
Instruction
JMP @A+DPTR
MOV DPTR, #data16
MOV /DPTR, #data16
INC DPTR
INC /DPTR
MOVC A,@A+DPTR
MOVC A,@A+/DPTR
MOVX A,@DPTR
MOVX A,@/DPTR
MOVX @DPTR, A
MOVX @/DPTR, A
DPD1
DPD1
A summary of data pointer instructions with fast context switching is listed
0
0
1
1
0
0
1
1
Table
DPD0
DPD0
Data Pointer Instructions
Data Pointer Decrement Behavior
Data Pointer Auto-Update
0
1
0
1
0
1
0
1
5-3.
DEC DPTR0
DEC DPTR0
INC DPTR0
INC DPTR0
INC DPTR
DPTR0++
DPTR0++
DPTR0--
DPTR0--
DPTR
Update Operation for MOVX and MOVC (DPU1 = 1 & DPU0 = 1)
Equivalent Operation for INC DPTR and INC /DPTR
DPS = 0
DPS = 0
DEC DPTR1
DEC DPTR1
INC DPTR1
INC DPTR1
INC /DPTR
DPTR1++
DPTR1++
DPTR1--
DPTR1--
/DPTR
DPS = 0
JMP @A+DPTR0
MOV DPTR0, #data16
MOV DPTR1, #data16
INC DPTR0
INC DPTR1
MOVC A,@A+DPTR0
MOVC A,@A+DPTR1
MOVX A,@DPTR0
MOVX A,@DPTR1
MOVX @DPTR0, A
MOVX @DPTR1, A
DEC DPTR1
DEC DPTR1
INC DPTR1
INC DPTR1
AT89LP3240/6440
INC DPTR
DPTR1++
DPTR1++
DPTR1--
DPTR1--
DPTR
Operation
DPS = 1
DPS = 1
DPS = 1
JMP @A+DPTR1
MOV DPTR1, #data16
MOV DPTR0, #data16
INC DPTR1
INC DPTR0
MOVC A,@A+DPTR1
MOVC A,@A+DPTR0
MOVX A,@DPTR1
MOVX A,@DPTR0
MOVX @DPTR1, A
MOVX @DPTR0, A
inTable
DEC DPTR0
DEC DPTR0
INC DPTR0
INC DPTR0
INC /DPTR
DPTR0++
DPTR0++
DPTR0--
DPTR0--
/DPTR
5-2.
Table
27