串行傳送的特點(diǎn) 隨著多微機(jī)系統(tǒng)的應(yīng)用和微機(jī)網(wǎng)絡(luò)的發(fā)展,通信功能顯得越來(lái)越重要。這里所說(shuō)的通信是指計(jì)算機(jī)與外界的信息交換。因此,通信既包括計(jì)算機(jī)與外部設(shè)備之間,也包括計(jì)算機(jī)和計(jì)算機(jī)之間的信息交換。由于串行通信所用的傳輸線少,并且可以借助現(xiàn)存的電話網(wǎng)進(jìn)行信息傳送,因此,特別適合于遠(yuǎn)距離傳送。對(duì)于那些與計(jì)算機(jī)相距不遠(yuǎn)的人機(jī)交換設(shè)備和串行存儲(chǔ)的外部設(shè)備(磁盤等),采用串行方式交換數(shù)據(jù)也很普遍。在實(shí)時(shí)控制和管理方面,采用多臺(tái)微處理機(jī)組成分級(jí)分布式控制系統(tǒng),其中各CPU之間的通信一般都是串行方式。所以,串行接口是微機(jī)應(yīng)用系統(tǒng)常用的接口。串行傳送是在一根傳輸線上一位一位的傳送,這根線既做數(shù)據(jù)線又做聯(lián)絡(luò)線,也就是說(shuō)要在一根傳輸線上既傳送數(shù)據(jù)信息,又傳送聯(lián)絡(luò)控制信息,這就是串行方式傳送的第一個(gè)特點(diǎn)。那么,如何來(lái)識(shí)別在一根線串行傳送的信息流中,哪一部分是聯(lián)絡(luò)信號(hào),哪一部分是數(shù)據(jù)信號(hào)。為解決這個(gè)問(wèn)題,就引出了串行通信的數(shù)據(jù)格式的約定。因此,串行傳送的第二個(gè)特點(diǎn)是它的數(shù)據(jù)格式有固定的要求(即固定的數(shù)據(jù)格式),分異步和同步數(shù)據(jù)格式,與此相應(yīng),就有異步通信和同步通信兩種方式。異步通信方式是按字符傳送的,而同步通信是按數(shù)據(jù)塊傳送的。
class="tags">標(biāo)簽: 單片機(jī) 串行通訊 雙工
class="time">上傳時(shí)間: 2014-12-27
class="username">上傳用戶:shen007yue
Bootloader是微處理器上電時(shí)運(yùn)行的第一段代碼,它可以通過(guò)通信接口實(shí)現(xiàn)對(duì)微處理器內(nèi)部應(yīng)用程序的更新升級(jí),為網(wǎng)絡(luò)化嵌入式產(chǎn)品的應(yīng)用程序升級(jí)帶來(lái)極大的便利。由于目前沒(méi)有統(tǒng)一嵌入式系統(tǒng)的Bootloader。基于NEC 78K0系列單片機(jī)自編程原理,設(shè)計(jì)出一個(gè)適用于78K0/Fx2系列單片機(jī)的Bootloader,并能夠通過(guò)單片機(jī)串口在線升級(jí)應(yīng)用程序。 Abstract: Bootloader is the first piece of code executed after microprocessor startup. It makes the embedded product’s firmware update conveniently through communication interface. However, no unified bootloader is available for all kinds of microprocessor products. Based on the principle of self-programming NEC 78K0s’ series, a useful Bootloader which is suitable for 78K0/Fx2s’ series MCU is designed,the design can update the application through serial ports.
class="tags">標(biāo)簽: Bootloader MCU 自編程
class="time">上傳時(shí)間: 2013-10-26
class="username">上傳用戶:fang2010
1.設(shè)計(jì)任務(wù)分析 原理: 當(dāng)按下開(kāi)關(guān),NE555計(jì)時(shí)器,4引腳于高電平,元件工作,電容C1充電,且2、6引腳達(dá)到高電平,此時(shí)輸出端3為低電平,揚(yáng)聲器發(fā)出響聲;開(kāi)關(guān)松開(kāi)后,電容C1放電,在2、6引腳大于1/3Vcc前,3端為低電平,揚(yáng)聲器工作;當(dāng)放電使2、6端電平小于1/3Vcc,3端為高電平,揚(yáng)聲器不工作。電容C2與滑動(dòng)變阻器一起控制引腳4的狀態(tài),使置零輸入端呈不同的臨界電壓,從而控制揚(yáng)聲器響音時(shí)間的長(zhǎng)短。當(dāng)電路轉(zhuǎn)換時(shí),2、6端電壓不同,使得輸出端3低電平電壓也不同,從而實(shí)現(xiàn)揚(yáng)聲器的雙音。
class="tags">標(biāo)簽: 555 定時(shí)器 雙音 門鈴電路
class="time">上傳時(shí)間: 2013-10-08
class="username">上傳用戶:懶龍1988
鐘是現(xiàn)代人類日常生活必不可少的工具,語(yǔ)音時(shí)鐘更是現(xiàn)在電子時(shí)鐘多功能化發(fā)展的一個(gè)方向。語(yǔ)音電子鐘具有突出的播報(bào)時(shí)間的功能,它被廣泛用在生活中的各種場(chǎng)合。本設(shè)計(jì)就是從日常生活中常見(jiàn)的事物入手,通過(guò)對(duì)語(yǔ)音電子鐘的設(shè)計(jì),讓我認(rèn)識(shí)到單片機(jī)已經(jīng)深入到我們生活的每個(gè)領(lǐng)域。 本文從語(yǔ)音電子鐘的設(shè)計(jì)原理、設(shè)計(jì)方案入手,詳細(xì)介紹了系統(tǒng)硬件設(shè)計(jì)、軟件設(shè)計(jì)及調(diào)試。在語(yǔ)音電子鐘的設(shè)計(jì)中,要處理好以下幾個(gè)關(guān)鍵:D/A(數(shù)/模)轉(zhuǎn)換,語(yǔ)音識(shí)別,人機(jī)接口,程序設(shè)計(jì)。D/A(數(shù)/模)和語(yǔ)音識(shí)別技術(shù)關(guān)系到時(shí)間的正確播報(bào),人機(jī)接口是播報(bào)時(shí)間和調(diào)整時(shí)間的關(guān)鍵。利用凌陽(yáng)SPCE061A單片機(jī)在語(yǔ)音識(shí)別和處理方面的優(yōu)點(diǎn),結(jié)合實(shí)踐,設(shè)計(jì)出有特色的語(yǔ)音電子鐘。
class="tags">標(biāo)簽: 單片機(jī) 語(yǔ)音 電子鐘
class="time">上傳時(shí)間: 2013-10-30
class="username">上傳用戶:feitian920
清單1 LSDAA: ADC R16,R16 ;十進(jìn)制數(shù)(在R16中)左移調(diào)整子程序 ADDAA: IN R6,SREG ;bcd碼相加調(diào)整子程序,先保存相加后的 LDI R17,$66 ;狀態(tài)the old status ADD R16,R17 ;再將和預(yù)加立即數(shù)$66 IN R17,SREG ;輸入相加后新?tīng)顟B(tài)(the new status) OR R6,R17 ;新舊狀態(tài)相或 SBRS R6,0 ;相或后進(jìn)位置位則跳行 SUBI R16,$60 ;否則減去$60(十位bcd不滿足調(diào)整條件) SBRS R6,5 ;半進(jìn)位置位則跳行 SUBI R16,6 ;否則減去$06(個(gè)位bcd不滿足調(diào)整條件) ROR R6 ;向高位BCD返還進(jìn)位位! RET
class="tags">標(biāo)簽: AVR 單片機(jī)實(shí)用 程序設(shè)計(jì)
class="time">上傳時(shí)間: 2013-10-08
class="username">上傳用戶:zh_901
MFC 六大技術(shù)之簡(jiǎn)化仿真(Console 程序) 第㆓篇【欲善工事先利其器】提供給對(duì) Visual C++ 整合環(huán)境全然陌生的朋友㆒個(gè)導(dǎo)引。 這㆒篇當(dāng)然不能取代 Visual C++ User's Guide 的㆞位,但對(duì)整個(gè)軟件開(kāi)發(fā)環(huán)境有全盤以 及概觀性的介紹,可以讓初學(xué)者迅速了解手㆖掌握的工具,以及它們的主要功能。 第㆔篇【淺出 MFC 程序設(shè)計(jì)】介紹㆒個(gè) MFC 程序的生死因果。已經(jīng)有 MFC 程序經(jīng) 驗(yàn)的朋友,不見(jiàn)得不會(huì)對(duì)本篇感到驚艷。根據(jù)我的了解,太多㆟使用 MFC 是「只知道 這么做,不知道為什么」;本篇詳細(xì)解釋 MFC 程序之來(lái)龍去脈,為初入 MFC 領(lǐng)域的 讀者奠定扎實(shí)的基礎(chǔ)。說(shuō)不定本篇會(huì)讓你有醍醐灌頂之感。
class="tags">標(biāo)簽: MFC 簡(jiǎn)體中文
class="time">上傳時(shí)間: 2013-12-16
class="username">上傳用戶:qq527891923
一,實(shí)驗(yàn)?zāi)康?1, 熟悉單片機(jī)定時(shí)/計(jì)數(shù)功能,掌握初始化編成方法; 2, 掌握順序控制程序的簡(jiǎn)單編程;掌握顯示數(shù)據(jù)的編程方法
class="tags">標(biāo)簽: 脈沖計(jì)數(shù)
class="time">上傳時(shí)間: 2013-10-15
class="username">上傳用戶:familiarsmile
詳細(xì)介紹了AD2S1200YSTZ資料
class="tags">標(biāo)簽: S1200 1200 YSTZ AD2
class="time">上傳時(shí)間: 2014-12-27
class="username">上傳用戶:hwl453472107
The MSP-FET430PIF is a Parallel Port interface (does not include target board) that is used to program and debug MSP430 FET tools and test boards through the JTAG interface. This interface is included in our FET tools, but sold without the development board. This interface uses a Parallel PC Port to communicate to the Debugger Software (IAR Kickstart software included) running on the PC. The interface uses the standard 14 pin header to communicate to the MSP430 device using the standard JTAG protocol. The flash memory can be erased and programmed in seconds with only a few keystrokes, and since the MSP430 flash is extremely low power, no external power supply is required. The tool has an integrated software environment and connects directly to the PC which greatly simplifies the set-up and use of the tool. The flash development tool supports development with all MSP430 flash parts. Features MSP430 debugging interface to connect a MSP430-Flash-device to a Parallel port on a PC Supports JTAG debug protocol (NO support for Spy-Bi-Wire (2-wire JTAG) debug protocol, Spy-Bi-Wire (2-wire JTAG) is supported by MSP-FET430UIF) Parallel Port cable and a 14-conductor target cable Full documentation on CD ROM Integrated IAR Kickstart user interface which includes: Assembler Linker Limulator Source-level debugger Limited C-compiler Technical specifications: Backwardly compatable with existing FET tool boards.
class="tags">標(biāo)簽: FET 430 PIF
class="time">上傳時(shí)間: 2013-10-26
class="username">上傳用戶:fengweihao158@163.com
The MSP-FET430U14 is a powerful flash emulation tool to quickly begin application development on the MSP430 MCU. It includes USB debugging interface used to program and debug the MSP430 in-system through the JTAG interface or the pin saving Spy Bi-Wire (2-wire JTAG) protocol. The flash memory can be erased and programmed in seconds with only a few keystrokes, and since the MSP430 flash is ultra-low power, no external power supply is required. The debugging tool interfaces the MSP430 to the included integrated software environment and includes code to start your design immediately. The MSP-FET430UIF development tools supports development with all MSP430 flash devices
class="tags">標(biāo)簽: JTAG MSP 430 USB
class="time">上傳時(shí)間: 2013-10-28
class="username">上傳用戶:13691535575