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In-circuit programming switch
发布时间:2017-03-18 阅读：次 [打印文章] [关闭窗口]- A simple bidirectional analog switch (MAX4525) facilitates in-circuit programming by providing dual service for two l塑封电感器ines (SDA滤波电感 and SCL) on the programmable device: for normal operation they connect to other circuitry, and for programming mode they connect to the programming header.
A similar version of this article appeared in the October 21, 2008 issue of ED magazine.
扁平型电感Many devices now available require programming through a serial bus such as I²C. This programming can be done during final test, after the circuit board has been assembled. In many cases the pins used for programming are used for something else during normal operation, and the bus itself can also be used for another function during normal operation.
A simple analo插件电感器g multiplexer circuit facilitates the in-circuit programming (Figure 1). The multiplexer shown 一体成型电感is a bidirectional analog switch (MAX4525). During normal operation, its input is pulled to ground by R1, causing the serial lines to connect to the rest of the circuit. During programming mode, the programming header asserts a logic high on the pin connected to the multiplexer input, causing the mux to switch over to the pins on the programming header.
Figure 1. This analog switch (MAX4525) enables in-circuit programming by providing dual service for two lines (SDA and SCL) on the programmable device: for normal operation they connect to other circuitry, and for programming mode they connect to the programming header.
An I²C bus is present in the figure, so pullup resistors are provided for other circuitry on the board. The device programmer that connects to the programming header must have its own pullup resistors. The series resistance added by the multiplexer should be accounted for by other circuitry on the board. To avoid forward-biasing the ESD diodes, the serial data lines should not go below ground or above the VCC voltage of the MAX4525.锡膏印刷设备的机架有限元模型引言锡膏印刷设备是表面组装技术(Surface Mount Technology，SMT)生产线的关键设备之一，是生产 工艺流程的第一道工序⋯，其印刷结果的好坏，直接 影响到后续工艺流程，甚至是产品的
一种车载开关电源的设计0 引言 由于开关电源技术的不断发展，开关电源被应用到越来越广泛的领域中。不但要求电源输出电压种类多元化，输入电压也多种多样，尤其直流输入电压范围比较广泛，本文设计了一种应用在列车上的电源。1 主电路
请教，我的LM2596ADJ为什么会固定输出1.235VR1是4.7k,R2是1.54k,按照计算应该输出5V才对，但我无论如何调整这两个电阻，输出一直是1.235V也就是参考电压。
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R2不应该接到+5，应该接到Pin4图画错了确实是我画错了，粗心大意
