參數(shù)資料
型號: AT80251G2D-SLSUM
廠商: Atmel
文件頁數(shù): 14/77頁
文件大?。?/td> 0K
描述: IC 8051 MCU ROMLESS 44PLCC
標準包裝: 972
系列: 8x251
核心處理器: C251
芯體尺寸: 8/16-位
速度: 24MHz
連通性: EBI/EMI,I²C,Microwire,SPI,UART/USART
外圍設備: POR,PWM,WDT
輸入/輸出數(shù): 32
程序存儲器類型: ROMless
RAM 容量: 1K x 8
電壓 - 電源 (Vcc/Vdd): 4.5 V ~ 5.5 V
振蕩器型: 內(nèi)部
工作溫度: -40°C ~ 85°C
封裝/外殼: 44-LCC(J 形引線)
包裝: 管件
21
AT/TSC8x251G2D
4135F–8051–11/06
Instruction Set
Summary
This section contains tables that summarize the instruction set. For each instruction
there is a short description, its length in bytes, and its execution time in states (one state
time is equal to two system clock cycles). There are two concurrent processes limiting
the effective instruction throughput:
Instruction Fetch
Instruction Execution
Table 20 to Table 32 assume code executing from on-chip memory, then the CPU is
fetching 16-bit at a time and this is never limiting the execution speed.
If the code is fetched from external memory, a pre-fetch queue will store instructions
ahead of execution to optimize the memory bandwidth usage when slower instructions
are executed. However, the effective speed may be limited depending on the average
size of instructions (for the considered section of the program flow). The maximum aver-
age instruction throughput is provided by Table 14 depending on the external memory
configuration (from Page Mode to Non-Page Mode and the maximum number of wait
states). If the average size of instructions is not an integer, the maximum effective
throughput is found by pondering the number of states for the neighbor integer values.
Table 14.
Minimum Number of States per Instruction for given Average Sizes
If the average execution time of the considered instructions is larger than the number of
states given by Table 14, this larger value will prevail as the limiting factor. Otherwise,
the value from Table 14 must be taken. This is providing a fair estimation of the execu-
tion speed but only the actual code execution can provide the final value.
Notation for Instruction
Operands
Table 15 to Table 19 provide notation for Instruction Operands.
Table 15.
Notation for Direct Addressing
Average size
of Instructions
(bytes)
Page Mode
(states)
Non-page Mode (states)
0 Wait
State
1 Wait
State
2 Wait States 3 Wait States 4 Wait States
11
2
3
4
5
6
22
4
6
8
10
12
3
6
9
12
15
18
44
8
12
16
20
24
5
10
15
20
25
30
Direct
Address
Description
C251
C51
dir8
A direct 8-bit address. This can be a memory address (00h-7Fh) or a
SFR address (80h-FFh). It is a byte (default), word or double word
depending on the other operand.
33
dir16
A 16-bit memory address (00:0000h-00:FFFFh) used in direct
addressing.
3–
相關PDF資料
PDF描述
AT80251G2D-SLSUL IC 8051 MCU ROMLESS 44PLCC
202516-1 CONN HOUSING COAXI SKT 42POS BLK
213522-1 M-SERIES KIT 34P V.35
201310-1 CONN HOUSING PLUG 75POS BLACK
213685-1 34P PLUG KIT,M-SERIES,CC,JS
相關代理商/技術(shù)參數(shù)
參數(shù)描述
AT804 制造商:POSEICO 制造商全稱:POSEICO 功能描述:PHASE CONTROL THYRISTOR
AT804S12 制造商:n/a 功能描述:Thyristor
AT804S16 制造商:POSEICO 制造商全稱:POSEICO 功能描述:PHASE CONTROL THYRISTOR
AT805-1.2KER 制造商: 功能描述:600mA Ultra Low Dropout Regulator 制造商:undefined 功能描述:600mA Ultra Low Dropout Regulator
AT805-3.3KER 制造商: 功能描述:600mA Ultra Low Dropout Regulator 制造商:undefined 功能描述:600mA Ultra Low Dropout Regulator