參數(shù)資料
型號(hào)： DS80C323-ECD
英文描述： High-Speed/Low-Power Micro
中文描述： High-Speed/Low-Power微
文件頁(yè)數(shù)： 12/42頁(yè)
文件大?。?/td> 1501K
代理商： DS80C323-ECD
DS80C320/DS80C323
12 of 42
DUAL DATA POINTER
Data memory block moves can be accelerated using the Dual Data Pointer (DPTR). The standard 8032
DPTR is a 16-bit value that is used to address off-chip data RAM or peripherals. In the
DS80C320/DS80C323, the standard 16-bit data pointer is called DPTR0 and is located at SFR addresses
82h and 83h. These are the standard locations. The new DPTR is located at SFR 84h and 85h and is
called DPTR1. The DPTR Select bit (DPS) chooses the active pointer and is located at the LSB of the
SFR location 86h. No other bits in register 86h have any effect and are set to 0. The user switches
between data pointers by toggling the LSB of register 86h. The increment (INC) instruction is the fastest
way to accomplish this. All DPTR-related instructions use the currently selected DPTR for any activity.
Therefore only one instruction is required to switch from a source to a destination address. Using the
Dual-Data Pointer saves code from needing to save source and destination addresses when doing a block
move. Once loaded, the software simply switches between DPTR and 1. The relevant register locations
are as follows.
DPL
82h
Low byte original DPTR
DPH
83h
High byte original DPTR
DPL1
84h
Low byte new DPTR
DPH1
85h
High byte new DPTR
DPS
86h
DPTR Select (LSB)
Sample code listed below illustrates the saving from using the dual DPTR. The example program was
original code written for an 8051 and requires a total of 1869 DS80C320/DS80C323 machine cycles. This
takes 299 μs to execute at 25 MHz. The new code using the Dual DPTR requires only 1097 machine
cycles taking 175.5 μs. The Dual DPTR saves 772 machine cycles or 123.5 μs for a 64-byte block move.
Since each pass through the loop saves 12 machine cycles when compared to the single DPTR approach,
larger blocks gain more efficiency using this feature.
64-BYTE BLOCK MOVE WITHOUT DUAL DATA POINTER
; SH and SL are high and low byte source address.
; DH and DL are high and low byte of destination address.
# CYCLES
2
3
2
2
2
2
MOV
MOV
MOV
MOV
MOV
MOV
MOVE:
; THIS LOOP IS PERFORMED THE NUMBER OF TIMES LOADED INTO R5, IN THIS EXAMPLE 64
MOVX
A, @DPTR
; READ SOURCE DATA BYTE
MOV
R1, DPL
; SAVE NEW SOURCE POINTER
MOV
R2, DPH
;
MOV
DPL, R3
; LOAD NEW DESTINATION
MOV
DPH, R4
;
MOVX
@DPTR, A
; WRITE DATA TO DESTINATION
INC
DPTR
; NEXT DESTINATION ADDRESS
MOV
R3, DPL
; SAVE NEW DESTINATION POINTER
MOV
R4, DPH
;
MOV
DPL, R1
; GET NEW SOURCE POINTER
MOV
DPH, R2
;
INC
DPTR
; NEXT SOURCE ADDRESS
DJNZ
R5, MOVE
; FINISHED WITH TABLE
R5, #64d
DPTR, #SHSL
R1, #SL
R2, #SH
R3, #DL
R4, #DH
; NUMBER OF BYTES TO MOVE
; LOAD SOURCE ADDRESS
; SAVE LOW BYTE OF SOURCE
; SAVE HIGH BYTE OF SOURCE
; SAVE LOW BYTE OF DESTINATION
; SAVE HIGH BYTE OF DESTINATION
2
2
2
2
2
2
3
2
2
2
2
3
3
相關(guān)PDF資料
PDF描述
DS80C323-MCD High-Speed/Low-Power Micro
DS80C320 High-Speed/Low-Power Microcontrollers
DS80C320-ECG Strain Relief
DS80C320-ECL High-Speed/Low-Power Microcontrollers
DS80C320-ENG High-Speed/Low-Power Microcontrollers
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS80C323-ECD+ 功能描述:8位微控制器 -MCU High-Speed Low-Power RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
DS80C323-ECD+T&R 制造商:Maxim Integrated Products 功能描述:MXMDS80C323-ECD+T&R HIGH-SPEED/LOW-POWER 制造商:Maxim Integrated Products 功能描述:MCU 8BIT CISC ROMLESS 3V 44TQFP - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC MCU 18MHZ HS/LP 44-TQFP
DS80C323-ECD+T&R 功能描述:8位微控制器 -MCU High-Speed Low-Power RoHS:否 制造商:Silicon Labs 核心:8051 處理器系列:C8051F39x 數(shù)據(jù)總線寬度:8 bit 最大時(shí)鐘頻率:50 MHz 程序存儲(chǔ)器大小:16 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:1.8 V to 3.6 V 工作溫度范圍:- 40 C to + 105 C 封裝 / 箱體:QFN-20 安裝風(fēng)格:SMD/SMT
DS80C323-ECG 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:High-Speed Microcontroller User Guide
DS80C323-ECL 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:High-Speed Microcontroller User Guide
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