All inputs of the C16x family have Schmitt-Trigger input characteristics. These Schmitt-Triggers are intended to always provide proper internal low and high levels, even if anundefined voltage level (between TTL-VIL and TTL-VIH) is externally applied to the pin.The hysteresis of these inputs, however, is very small, and can not be properly used in anapplication to suppress signal noise, and to shape slow rising/falling input transitions.Thus, it must be taken care that rising/falling input signals pass the undefined area of theTTL-specification between VIL and VIH with a sufficient rise/fall time, as generally usualand specified for TTL components (e.g. 74LS series: gates 1V/us, clock inputs 20V/us).The effect of the implemented Schmitt-Trigger is that even if the input signal remains inthe undefined area, well defined low/high levels are generated internally. Note that allinput signals are evaluated at specific sample points (depending on the input and theperipheral function connected to it), at that signal transitions are detected if twoconsecutive samples show different levels. Thus, only the current level of an input signalat these sample points is relevant, that means, the necessary rise/fall times of the inputsignal is only dependant on the sample rate, that is the distance in time between twoconsecutive evaluation time points. If an input signal, for instance, is sampled throughsoftware every 10us, it is irrelevant, which input level would be seen between thesamples. Thus, it would be allowable for the signal to take 10us to pass through theundefined area. Due to the sample rate of 10us, it is assured that only one sample canoccur while the signal is within the undefined area, and no incorrect transition will bedetected. For inputs which are connected to a peripheral function, e.g. capture inputs, thesample rate is determined by the clock cycle of the peripheral unit. In the case of theCAPCOM unit this means a sample rate of 400ns @ 20MHz CPU clock. This requiresinput signals to pass through the undefined area within these 400ns in order to avoidmultiple capture events.For input signals, which do not provide the required rise/fall times, external circuitry mustbe used to shape the signal transitions.In the attached diagram, the effect of the sample rate is shown. The numbers 1 to 5 in thediagram represent possible sample points. Waveform a) shows the result if the inputsignal transition time through the undefined TTL-level area is less than the time distancebetween the sample points (sampling at 1, 2, 3, and 4). Waveform b) can be the result ifthe sampling is performed more than once within the undefined area (sampling at 1, 2, 5,3, and 4).Sample points:1. Evaluation of the signal clearly results in a low level2. Either a low or a high level can be sampled here. If low is sampled, no transition willbe detected. If the sample results in a high level, a transition is detected, and anappropriate action (e.g. capture) might take place.3. Evaluation here clearly results in a high level. If the previous sample 2) had alreadydetected a high, there is no change. If the previous sample 2) showed a low, atransition from low to high is detected now.
上传时间： 2013-10-23
上传用户：copu
All inputs of the C16x family have Schmitt-Trigger input characteristics. These Schmitt-Triggers are intended to always provide proper internal low and high levels, even if anundefined voltage level (between TTL-VIL and TTL-VIH) is externally applied to the pin.The hysteresis of these inputs, however, is very small, and can not be properly used in anapplication to suppress signal noise, and to shape slow rising/falling input transitions.Thus, it must be taken care that rising/falling input signals pass the undefined area of theTTL-specification between VIL and VIH with a sufficient rise/fall time, as generally usualand specified for TTL components (e.g. 74LS series: gates 1V/us, clock inputs 20V/us).The effect of the implemented Schmitt-Trigger is that even if the input signal remains inthe undefined area, well defined low/high levels are generated internally. Note that allinput signals are evaluated at specific sample points (depending on the input and theperipheral function connected to it), at that signal transitions are detected if twoconsecutive samples show different levels. Thus, only the current level of an input signalat these sample points is relevant, that means, the necessary rise/fall times of the inputsignal is only dependant on the sample rate, that is the distance in time between twoconsecutive evaluation time points. If an input signal, for instance, is sampled throughsoftware every 10us, it is irrelevant, which input level would be seen between thesamples. Thus, it would be allowable for the signal to take 10us to pass through theundefined area. Due to the sample rate of 10us, it is assured that only one sample canoccur while the signal is within the undefined area, and no incorrect transition will bedetected. For inputs which are connected to a peripheral function, e.g. capture inputs, thesample rate is determined by the clock cycle of the peripheral unit. In the case of theCAPCOM unit this means a sample rate of 400ns @ 20MHz CPU clock. This requiresinput signals to pass through the undefined area within these 400ns in order to avoidmultiple capture events.
上传时间： 2014-04-02
上传用户：han_zh
This application note demonstrates how to write an Inter Integrated Circuit bus driver (I2C) for the XA-S3 16-bitMicrocontroller from Philips Semiconductors.Not only the driver software is given. This note also contains a set of (example) interface routines and a smalldemo application program. All together it offers the user a quick start in writing a complete I2C system applicationwith the PXAS3x.The driver routines support interrupt driven single master transfers. Furthermore, the routines are suitable foruse in conjunction with real time operating systems.
上传时间： 2013-11-02
上传用户：zw380105939
I2C interface, is a very powerful tool for system designers. Theintegrated protocols allow systems to be completely software defined.Software development time of different products can be reduced byassembling a library of reusable software modules. In addition, themultimaster capability allows rapid testing and alignment ofend-products via external connections to an assembly-line computer.The mask programmable 87LPC76X and its EPROM version, the87LPC76X, can operate as a master or a slave device on the I2Csmall area network. In addition to the efficient interface to thededicated function ICs in the I2C family, the on-board interfacefacilities I/O and RAM expansion, access to EEPROM andprocessor-to-processor communications.
标签： microcontro Using 76X LPC
上传时间： 2013-12-30
上传用户：Artemis
#include <reg51.h>#include<intrins.h> #define BUSY1 (DQ1==0) sbit DQ1 = P0^4; unsigned char idata TMP; unsigned char idata TMP_d; unsigned char f; void wr_ds18_1(char dat);unsigned char rd_ds18_1(); /***************延时程序，单位us,大于10us*************/void time_delay(unsigned char time){ time=time-10; time=time/6; while(time!=0)time--;} /*****************************************************//* reset ds18b20 *//*****************************************************/void ds_reset_1(void){ unsigned char idata count=0; DQ1=0; time_delay(240); time_delay(240); DQ1=1; return;}
上传时间： 2013-10-29
上传用户：sssnaxie
1、程序的基本格式先介绍二条伪指令：EQU ——标号赋值伪指令ORG ——地址定义伪指令PIC16C5X在RESET后指令计算器PC被置为全“1”，所以PIC16C5X几种型号芯片的复位地址为：PIC16C54/55：1FFHPIC16C56：3FFHPIC16C57/58：7FFH一般来说，PIC的源程序并没有要求统一的格式，大家可以根据自己的风格来编写。但这里我们推荐一种清晰明了的格式TITLE This is ⋯⋯ ；程序标题；--------------------------------------；名称定义和变量定义；--------------------------------------F0 EQU 0RTCC EQU 1PC EQU 2STATUS EQU 3FSR EQU 4RA EQU 5RB EQU 6RC EQU 7┋PIC16C54 EQU 1FFH ；芯片复位地址PIC16C56 EQU 3FFHPIC16C57 EQU 7FFH；-----------------------------------------ORG PIC16C54 GOTO MAIN ；在复位地址处转入主程序ORG 0 ；在0000H开始存放程序；-----------------------------------------；子程序区；-----------------------------------------DELAY MOVLW 255┋RETLW 0；------------------------------------------；主程序区；------------------------------------------MAINMOVLW B‘00000000’TRIS RB ；RB已由伪指令定义为6，即B口┋LOOPBSF RB，7 CALL DELAYBCF RB，7 CALL DELAY┋GOTO LOOP；-------------------------------------------END ；程序结束注:MAIN标号一定要处在0页面内。2、程序设计基础
上传时间： 2013-11-14
上传用户：cjf0304
晶振：12M TEMPER_L EQU 36H TEMPER_H EQU 35H TEMPER_NUM EQU 60H FLAG1 BIT 00H DQ BIT P3.3AAA:MOV SP,#70H LCALL GET_TEMPER LCALL TEMPER_COV LJMP AAA NOP ;------------------读出转换后的温度值 GET_TEMPER: SETB DQ ; 定时入口 BCD:LCALL INIT_1820 JB FLAG1,S22 LJMP BCD ; 若DS18B20不存在则返回S22:LCALL DELAY1 MOV A,#0CCH ; 跳过ROM匹配------0CC LCALL WRITE_1820 MOV A,#44H ; 发出温度转换命令 LCALL WRITE_1820 NOP LCALL DELAY LCALL DELAY CBA:LCALL INIT_1820 JB FLAG1,ABC LJMP CBA ABC:LCALL DELAY1 MOV A,#0CCH ; 跳过ROM匹配 LCALL WRITE_1820 MOV A,#0BEH ; 发出读温度命令 LCALL WRITE_1820 LCALL READ_18200 ;READ_1820 RET ;------------------读DS18B20的程序,从DS18B20中读出一个字节的数据 READ_1820: MOV R2,#8 RE1: CLR C
上传时间： 2013-10-09
上传用户：heart_2007
PLC TM卡开发系统汇编程序(ATM8051) ;***************** 定义管脚*************************SCL BIT P1.0SDA BIT P1.1GC BIT P1.2BZ BIT P3.6LEDI BIT P1.4LEDII BIT P1.5OK BIT 20H.1OUT1 BIT P1.3OUT2 BIT P1.0OUT3 BIT P1.1RXD BIT P3.0TXD BIT P3.1PCV BIT P3.2WPC BIT P3.3RPC BIT P3.5LEDR BIT P3.4LEDL BIT P3.6TM BIT P3.7;********************定义寄存器***********************ROMDTA EQU 30H;NUMBY EQU 61H;SLA EQU 60H;MTD EQU 2FH;MRD EQU 40H;TEMP EQU 50H;;ORG 00H;;INDEX:MOV P1, #00H;MOV P2, #0FFHMOV MTD ,#00HCALL REEMOV R0,40HCJNE R0,#01,NO;MOV P2,#1CHLJMP VIMEN MOV P2,#79HACALL TOUCHRESET ;JNC NO ;CALL READTM ;CJNE A,#01H,NO;NOPMOV MTD, #00HCALL WEENOPMOV P2,#4AHSETB BZCALL TIMECLR BZMOV PCON, #0FFHVIME:CALL TIME1CALL TOUCHRESETJNC VIMECALL READTMCJNE A, #01H,VIME;NOPNOPNOPIII: MOV MTD,#00HCALL REECALL BBJNB OK,NO1LJMP ZHUNO1:MOV MTD,#10H
上传时间： 2014-03-24
上传用户：448949
51汇编程序实例：举一例说明：流水灯加数码管 LOOP: ; 标号CLR P2.6 ;选中p2.6 数码管左边的8字使能SETB P2.7 ;p2.7不使能。 右边的数码管消隐MOV P0,#28H ;把28h送p0口；数码管显示 0LCALL DELAY ;延时MOV P0,#0FFH ;0ffh 送p0口，数码管清除CLR P1.0 ;点亮p1.0发光管MOV P0,#7EH ;把7eh送p0口；数码管显示 1LCALL DELAYMOV P0,#0FFHCLR P1.1 ;点亮p1.0发光管CLR P1.0 ;点亮p1.0发光管MOV P0,#0A2H ;数码管显示 2LCALL DELAYMOV P0,#0FFHCLR P1.2CLR P1.1CLR P1.0MOV P0,#62H ;数码管显示 3LCALL DELAYMOV P0,#0FFHCLR P1.3CLR P1.2CLR P1.1CLR P1.0MOV P0,#74H ;数码管显示 4LCALL DELAYMOV P0,#0FFHCLR P1.4CLR P1.3CLR P1.2CLR P1.1CLR P1.0MOV P0,#61H ;数码管显示 5;LCALL DELAYMOV P0,#0FFHCLR P1.5CLR P1.4CLR P1.3CLR P1.2CLR P1.1CLR P1.0MOV P0,#21H ; 数码管显示 6LCALL DELAYMOV P0,#0FFHCLR P1.6CLR P1.5CLR P1.4CLR P1.3CLR P1.2CLR P1.1CLR P1.0MOV P0,#7AH ; 数码管显示 7LCALL DELAYMOV P0,#0FFHCLR P1.7CLR P1.6CLR P1.5CLR P1.4CLR P1.3CLR P1.2CLR P1.1CLR P1.0MOV P0,#20H ; 数码管显示 8LCALL DELAYMOV P0,#0FFHLCALL DELAYMOV P0,#0FFHMOV P1,#0FFH;程序到此结果为左边的数码管显示0，1，2，3，4，5，6，7，8;p1.0------------p1.7指示灯依次点亮SETB P2.6 ; 左边的8消隐CLR P2.7 ;选中p2.7 数码管右边的8字使能 ，；MOV P0,#28HLCALL DELAYMOV P0,#0FFHMOV P1,#0FFHCLR P1.0MOV P0,#7EHLCALL DELAYMOV P0,#0FFHMOV P1,#0FFHCLR P1.1MOV P0,#0A2HLCALL DELAYMOV P0,#0FFHMOV P1,#0FFHCLR P1.2MOV P0,#62HLCALL DELAYMOV P0,#0FFHMOV P1,#0FFHCLR P1.3MOV P0,#74HLCALL DELAYMOV P0,#0FFHMOV P1,#0FFHCLR P1.4MOV P0,#61HLCALL DELAYMOV P0,#0FFHMOV P1,#0FFHCLR P1.5MOV P0,#21HLCALL DELAYMOV P0,#0FFHMOV P1,#0FFHCLR P1.6MOV P0,#7AHLCALL DELAYMOV P0,#0FFHMOV P1,#0FFHCLR P1.7MOV P0,#20HLCALL DELAYMOV P0,#0FFHMOV P1,#0FFHMOV P0,#0FFHMOV P1,#0FFH;这一段和上一段基本相同， 不同的是右边的数码管依次显示012345678，左边的不亮；;同时p1口的灯流动显示：AJMP LOOP; 注意： 程序运行到此跳转到开始标号，重复执行：DELAY: ;延时子程序；参考前面的教程：CLR P3.3 ;注意小喇叭在3.3口， 这里可以使小喇叭发出嗒，嗒声MOV R7,#255NOPNOPD1:MOV R6,#255setb p3.3D2: DJNZ R6,D2clr p3.3DJNZ R7,D1SETB P3.3RETENDLOOP: ； 标号CLR P2.6 ；选中p2.6 数码管左边的8字使能SETB P2.7 ；p2.7不使能。 右边的数码管消隐MOV P0,#28H ；把28h送p0口；数码管显示 0 ;28为1010000LCALL DELAY ； 延时程序MOV P0,#0FFH ；0ffh 送p0口，数码管清除；P0口为11111111CLR P1.0 ；点亮p1.0发光管； P1。0为电平，P0口为11111110MOV P0,#7EH ；把7eh送p0口；数码管显示 1； P1。0为低电平，P0口为11111110LCALL DELAY ； 延时程序MOV P0,#0FFHMOV P0,#0FFH ；0ffh 送p0口，数码管清除；P0口为11111111 清一次显示这条是清显示的
上传时间： 2013-10-31
上传用户：gundamwzc
用单片机配置FPGA—PLD设计技巧 Configuration/Program Method for Altera Device Configure the FLEX Device You can use any Micro-Controller to configure the FLEX device–the main idea is clocking in ONE BITof configuration data per CLOCK–start from the BIT 0The total Configuration time–e.g. 10K10 need 15K byte configuration file•calculation equation–10K10* 1.5= 15Kbyte–configuration time for the file itself•15*1024*8*clock = 122,880Clock•assume the CLOCK is 4MHz•122,880*1/4Mhz=30.72msec
上传时间： 2013-10-09
上传用户：a67818601
