阅读:1341回复:5
调了两天都不通啊!!!(那边没人,只好过来问了)
调了两天都不通啊!!!
硬件采用与52串口同步通信,即txd接7706-SCLK,rxd接7706的Din和Dout。(datasheet上的典型电路) 7706寄存器读写和初始化程序如下: unsigned char read_7706() { unsigned char dat; RI=0; while(RI==0); dat=SBUF; return dat; } void write_7706(unsigned char dat) { TI=0; SBUF=dat; while(TI==0); TI=0; } /*;*** AD7706 ANALOGUE TO DIGITAL CONVERTOR CONFIGURATION ********************************* ; ;This is the AD7706 configuration routine ; ;The ADC configuration steps are as follows: ; 1)Write to the communications register specifying that the next operation to be a ; write to the clock register,select AIN1 (ie 0x20). ; ; 2)Write to the clock register appropiate settings (ie 0x0C) ; - Mclk out enabled ; - Input clock divided by two ; - Update rate of 20 ms or 50 Hz which gives ; a 3 dB digital filter cutoff of 13.1 Hz ; ; 3)Write to the comms register specifying that the next operation to be a write to ; the setup register and a calibration on channel 3 (ie 0x13) ; ; 4)Write to the setup register appropiate settings (0x54) ; - perform self calibration on channel 3 ; - Gain of 4 (max input voltage 0.625 !!) ; - unipolar mode ; - on chip buffer enabled ; - clear Fsync to begin a conversion */ void init_7706() { write_7706(0x20); //1.write communication reg,next write clock reg write_7706(0x0C); //2.write clock reg, write_7706(0x08); //.write communication register,next read communication register temp=read_7706(); //read communication register write_7706(0x28); //next read clock register temp=read_7706(); //read clock register write_7706(0x10); //3.write communication register,next write set register write_7706(0x40); //4.write set register write_7706(0x08); //next read communication register temp=read_7706(); //read communication register write_7706(0x18); //next read set register temp=read_7706(); //read set register } 发现读出的寄存器值均为0xff,初始化不成功的。软硬件和资料是符合的啊,怎么会有这么奇怪的问题呢??? |
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沙发#
发布于:2002-11-04 17:22
不好意思,我问的是关于AD7706的使用,题目没有写清楚,sorry!
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板凳#
发布于:2002-11-04 17:38
在付值语句中添加中间变量试一下啦。
ACC=SBUF; dat=ACC; 不一定行的。 |
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地板#
发布于:2002-11-05 12:06
我认为此接法绝对有问题,是不是你还没有真正理解。
rxd在作为通讯口时,只是一个输入信号啊,怎能和din/dout连在一块,又输入又输出呢? 你应该仔细研究一下时序。 会不会是,这两个管脚只是当作普通io使用? [编辑 - 11/5/02 by hglzw] |
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地下室#
发布于:2002-11-05 16:27
呵呵,请看一下“有关D12端点读取的问题”,偶还是解决不了。
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5楼#
发布于:2002-11-06 10:31
我认为此接法绝对有问题,是不是你还没有真正理解。 电路是没问题的,DS中的典型电路嘛。问题已经解决了,是时序问题,7706串口读写是先高字节后低字节,而52则是先低后高。所以要通过转换来实现每次读写。 昨天看时序图的时候突然发现的,呵呵。这种细节问题还真是麻烦人啊 |
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