时钟芯片驱动

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c51/2051新线路板(1#,89c51)上DS1302的主电源VCC2连到VCC上，VCC通过开关连到电池正极。DS1302的备用电源VCC1直接连到电池正极。故障现象：

安装好后切换开关状态，芯片强烈发热。测量压降，类似短路。仅将VCC1断开，故障消失；仅将VCC2断路，加电时正常，切换开关后发热，这是最令人奇怪的。将芯片换到旧的89c51线路板(2#,89c51)上，（VCC1，VCC2短接连到VCC）故障消失。

新旧线路板逻辑连接都是一样的。在新板上只留下DS1302芯片，其他芯片均移走仍然出现故障。此时与芯片连接的元件只有MAX232的去藕电容。在新板上使用一只1u的电容，在旧板上是0.1u的。判断当开关闭合时，电容充电，DS1302 VCC1的电压出现瞬断造成内部电路紊乱。焊下该电容，故障现象消失。

匪夷所思的是1#在连接上指示LED，更换了电源开关后故障又出现。最怀疑的是干扰，但看来也还没有找到根本原因。

有些怀疑芯片WP是否应常置位，否则三线输入在断电过程中是否会产生紊乱。

再次试验。用于赤道仪2051的线路板(3#,89c2051)（1u电容），取下MCU，工作正常。将MCU1加上，从而DS1302三线连到了单片机上，异常现象出现。重新编程，令端口上电后即复位（但仍会有正脉冲），现象依旧。

换到1#板。取下MCU，工作正常；加上MCU，异常。重新编程，令端口上电后即复位，同时，只在写时钟前复位WP，写结束后即置位。故障现象消失。试验时钟8小时，准确。

3#板。P1.0，P1.1加上拉电阻。原程序，芯片发热。重新编程，使WP置位。发热现象消失。

好景不长，3#又出现问题。将1u电容取下，故障消失。加上，故障出现。

3#线路板2051单片机，加0.1u电容，WP置位。试验一晚上不发热。



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	时钟芯片驱动 [2006-05-24] 以时钟芯片DS1302为例。 NFL sports jerseys are a abundant means for any fan to appearance cheap nfl jerseys their abutment for their respected team .cheap nfl jerseys As you attending at the altered available, you ability admiration what some cheap nfl jerseys of your alternatives are as you aswell cheap nfl jerseys activate the seek for one that is cheap nfl jerseys acceptable for you.Typically, 2013 super bowl jerseys you will exchange that NFL sports jerseys cheap nike nfl jerseys are advised as replicas of the official bold jersey your respected players wear. They are fabricated of a college superior nylon allowing the derma beneath them to breathe easily. Best of all,cheap nfl jerseys the faculty superior versions ravens jerseys will endure a continued time acknowledgment to the added material. Over the years,49ers jerseys these jerseys accept become cheap nfl jerseys absolute accepted acknowledgment to the cheap nfl jerseys able followings the teams have. Most break at home admirers like to action the jersey of their respected player, while they acclamation at the bold on nfl jerseys cheap the big screen. Those that do Cheap Nike NFL jerseys accomplish it to the big game, they adore accepting their on to appearance the aggregation they cheap nfl jerseys are admitting and they tend to attending ablaze in a affiliate marketer of hundreds cutting the absolute above mentioned jersey When you are searching at the altered NFL sports jerseys, you will apprehension that they accept a altered appearance 2013 super bowl jerseys depending on gender.cheap authentic jerseys The ones advised nfl jerseys cheap for men are about abutting cut to the close and aggregate cheap jerseys china out in the accept areas Women will exchange a added airy close band that gives them added nfl jerseys china comfort Their options cheap nfl jerseys can be bigger in the chest breadth and smaller in the amateur and sides. There are cheap jerseys china even some risque jersey sources cheap nfl jerseys of the added adventuresome women to wear. 管脚排列（extracted from datasheet）时钟上升沿写，下降沿读。 Vcc2是主电源；Vcc1是备用电源。指令集（extraced from datasheet） C51编程：文件头 //时钟芯片声明代码开始－－－－－－－－－－－－－－－－ //定义管脚Time-Keeping Chip TK sbit TK_CLK=P3^3; sbit TK_CE=P3^6; sbit TK_IO=P3^7; //定义指令 #define TK_RDSEC 0x81 #define TK_WRSEC 0x80 #define TK_RDMIN 0x83 #define TK_WRMIN 0x82 #define TK_RDHR 0x85 #define TK_WRHR 0x84 #define TK_RDDATE 0x87 #define TK_WRDATE 0x86 #define TK_RDMON 0x89 #define TK_WRMON 0x88 #define TK_RDWEEK 0x8B #define TK_WRWEEK 0x8A #define TK_RDYR 0x8D #define TK_WRYR 0x8C #define TK_WRWP 0x8E #define TK_RDCLKBURST 0xBF #define TK_WRCLKBURST 0xBE //函数声明 void tkwrite(unsigned char address,unsigned char value); unsigned char tkread(unsigned char address); void tkreadclock(unsigned char clock[]); void tksetclock(unsigned char clock[]); unsigned char bcd2char(unsigned char bcd); unsigned char char2bcd(unsigned char ch); //时钟芯片声明代码结束－－－－－－－－－－－－－－－－主程序 //时钟芯片初始化开始－－－－－－－－－－－－－－－ tkwrite(TK_WRWP,0); tkwrite(TK_WRSEC,0); //时钟芯片初始化结束－－－－－－－－－－－－－－－调用 unsigned char clk[8]; ...... tksetclock(clk); ...... tkreadclock(clk); ...... 子程序 //时钟芯片驱动代码开始－－－－－－－－－－－－－－－－ /************************************************* TimeKeeping Chip TK 写1个字节，仅涉及CLK ***********************************************/ void tksendbyte(unsigned char value){ unsigned char i; for(i=0;i<8;i++){ if(0x01&value) TK_IO=1; else TK_IO=0; TK_CLK=0; TK_CLK=1; value>>=1; } } /*********************************************** TimeKeeping Chip TK 读1个字节，仅涉及CLK ***********************************************/ unsigned char tkreadbyte(void){ unsigned char i,res; res=0; TK_IO=1; for(i=0;i<8;i++){ TK_CLK=1; TK_CLK=0; res/=2; if(TK_IO) res+=128; } return res; } /*********************************************** TimeKeeping Chip TK 在地址address处写入value ***********************************************/ void tkwrite(unsigned char address,unsigned char value){ TK_CLK=0; TK_CE=0; TK_CE=1; tksendbyte(address); tksendbyte(value); TK_CLK=0; TK_CE=0; } /*********************************************** TimeKeeping Chip TK 从地址address读出一个字节返回读出值 ***********************************************/ unsigned char tkread(unsigned char address){ unsigned char res; TK_CLK=0; TK_CE=0; TK_CE=1; tksendbyte(address); res=tkreadbyte(); TK_CE=0; return res; } /********************************************** bcd和char格式的转换 ***********************************************/ unsigned char bcd2char(unsigned char bcd){ unsigned char res; res=bcd/16; res=10; res+=bcd%16; return res; } unsigned char char2bcd(unsigned char ch){ unsigned char res; res=ch/10; res=16; res+=ch%10; return res; } /************************************************ TimeKeeping Chip TK burst读时钟转为char输出 ***********************************************/ void tkreadclock(unsigned char clock[]){ unsigned char i; TK_CLK=0; TK_CE=0; TK_CE=1; tksendbyte(TK_RDCLKBURST); for(i=0;i<8;i++){ clock[i]=bcd2char(tkreadbyte()); } TK_CE=0; } /*********************************************** TimeKeeping Chip TK 转为bcd后burst写时钟 *************************************************/ void tksetclock(unsigned char clock[]){ unsigned char i; TK_CLK=0; TK_CE=0; TK_CE=1; tksendbyte(TK_WRCLKBURST); for(i=0;i<8;i++){ tksendbyte(char2bcd(clock[i])); } TK_CE=0; } //时钟芯片驱动代码结束－－－－－－－－－－－－－－－－ [2006-10-7] 发现奇怪的现象。 c51/2051新线路板(1#,89c51)上DS1302的主电源VCC2连到VCC上，VCC通过开关连到电池正极。DS1302的备用电源VCC1直接连到电池正极。故障现象：安装好后切换开关状态，芯片强烈发热。测量压降，类似短路。仅将VCC1断开，故障消失；仅将VCC2断路，加电时正常，切换开关后发热，这是最令人奇怪的。将芯片换到旧的89c51线路板(2#,89c51)上，（VCC1，VCC2短接连到VCC）故障消失。新旧线路板逻辑连接都是一样的。在新板上只留下DS1302芯片，其他芯片均移走仍然出现故障。此时与芯片连接的元件只有MAX232的去藕电容。在新板上使用一只1u的电容，在旧板上是0.1u的。判断当开关闭合时，电容充电，DS1302 VCC1的电压出现瞬断造成内部电路紊乱。焊下该电容，故障现象消失。 1#换成3300p电容，反复试验，正常。 [2006-10-11] 匪夷所思的是1#在连接上指示LED，更换了电源开关后故障又出现。最怀疑的是干扰，但看来也还没有找到根本原因。 [2006-10-12] 有些怀疑芯片WP是否应常置位，否则三线输入在断电过程中是否会产生紊乱。再次试验。用于赤道仪2051的线路板(3#,89c2051)（1u电容），取下MCU，工作正常。将MCU1加上，从而DS1302三线连到了单片机上，异常现象出现。重新编程，令端口上电后即复位（但仍会有正脉冲），现象依旧。换到1#板。取下MCU，工作正常；加上MCU，异常。重新编程，令端口上电后即复位，同时，只在写时钟前复位WP，写结束后即置位。故障现象消失。试验时钟8小时，准确。 [2006-10-13] 3#板。P1.0，P1.1加上拉电阻。原程序，芯片发热。重新编程，使WP置位。发热现象消失。所以似乎：WP应常置位，仅在写入前复位。好景不长，3#又出现问题。将1u电容取下，故障消失。加上，故障出现。 [2006-10-14] 1#线路板51单片机，0.003u电容，WP置位。试验不发热。 3#线路板2051单片机，无电容，WP置位。试验一晚上不发热。可是，1#重新组装记录器后故障再出现·····，天理难容啊 [2006-10-15] 3#线路板2051单片机，加0.1u电容，WP置位。试验一晚上不发热。