有没有那位兄弟做成功过下面这个电容表？
One of the smallest atmegas, the atmega8, was selected to do the job, as the IO and resource requirements are only limited. The power supply consists of a 9V battery linearly regulated to 5V using a 7805, to get a stable and quiet supply. The rather large 47 uF tantalum decoupling cap might be overkill, but was selected to further stabilize the power supply.http://cache.amobbs.com/bbs_upload782111/files_12/ourdev_420975.png
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The measurement circuit needs a little explanation. The meter can be in three modes: low range measuring, high range measuring or discharging. These modes are defined by the states of PD5 and PD6. When discharging PD6 pulls low and the capacitor is discharged through R7 (220). At high range measuring PD5 pulls high, charging the capacitor through R8 (1.8K) and PD6 is high impedance to allow the analog comperator to watch the voltage. At low range measuring PD5 is also high impedance and only R6 (1.8Meg) charges the capacitor.
The LCD must be a standard HD44780 compatible 16x2 character display. The connector shown above is a 10 pin flat cable, with a pinout selected for ease of routing on a stripboard. The cable must connect to the LCD as follows:
The circuit was implemented on stripboard and built into a simple plastic case. The top of the case was cut to hold the button, the LED and the LCD, which was all hot-melt glued:
Software
Beside the capacitance measurement logic and configuring the mcu's timer and analog comperator, the following more general tasks are solved by the software:
Assembler optimized fixed point math multiplication
EEPROM read and write functions
Delay milliseconds function
Conversion of numbers to ascii with decimal and decade control (pF, nF, uF, mF)
Hold-down-single-button menu implementation
HD44780 compatible LCD char and string routines
The software can run on atmega8 and on atmega48/88/168 family mcu's. A single line of code dealing with timer setup must be changed according to what family of mcu is used. 程序来了．
Capmeter源文件ourdev_420979.zip(文件大小:7K) (原文件名:Capmeter.zip) LZ怎么不先尝试着做一下,然后分享一下经验呢? 已经做了一个，初始化显示没问题，测量时死活没显示．应该还有问题．．
所以看看有没有人做过？ http://www.ouravr.com/bbs/bbs_content.jsp?bbs_sn=436997&bbs_page_no=1&search_mode=3&search_text=fsclub&bbs_id=9999 LZ对它的工作原理和程序的算法理解么?如果理解的话,自己都应该可以写一个出来的. 本人网站上有一电容表套件，可以测道引线的电容，应该比楼主说的那个成本低，看图片。 （网址：www.jyetech.com）
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(原文件名:CapMeter_6.jpg) To: ywl0409 老黄牛
之前是按照图和程序做的．没有去深入理解．现在再看．
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(原文件名:IMG_4498.jpg) 00000 做了个电容箱，用43B测量输出电容值（10nF以下值和个别几十nF）显示不稳，跳变比较大，用LCR电桥测也是读数不稳！把电容拆下来直接测量是没问题的，但是接到电路里就不稳了。电容箱是数字的，用交流电源供电，通过控制继电器通断输出不同的电容值。
哪位大侠帮我分析一下？是电路布线分布电容的影响？还是单片机工作的电磁干扰影响？
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