单片机实现简易波形发生器Word格式.docx

1、显示段码如表1.1所示。表1.1 共阴极数码管显示段码显示字符12345678显示段码3FH06H5BH4FH66H6DH7DH07H7FH9AbCDEF灭6FH77H7CH39H5EH79H71H00H1.1.2 键盘电路原理如图1.2所示为44的矩阵式键盘和单片机的P3口相连，行连接P3.0-P3.3，列连接P3.4-P3.5。用扫描法对按键进行扫描，先将所有行置0，所有列置1，当有按键按下时，通过对P3口的状态查询则按下的按键所在列将为0，其余仍未1，通过延时去抖动判断是否真有按键按下，若有，则逐行扫描，判断按键所在行，最后返回按键键码，并去执行相应按键的程序。返回键码如表1.2所示。按

2、键返回键码EEHDEHBEH7EHEDHDDHBDHBEBHDBHBBH7BHE7HD7HB7H表1.2 键盘扫描返回键码1.1.3 D/A转换电路原理如图1.3所示为AD/DA转换芯片PCF8591和单片机相连的电路，其中4路D/A，一路A/D，简易波形发生器用到的为D/A转换，单片机的P2.0及P2.1口和PCF8591的时钟线SCL、数据线SDA相连，通过I2C串行总线向PCF8591发送数据并进行数字量转换成模拟量后输出。1.2 元器件选择及说明 简易波形发生器是由单片机向D/A转换器中输入数字量，通过D/A转换成模拟量从而输出波形，因此用到的器件主要有单片机STC89C51，AD/D

3、A转换芯片PCF8591，四位共阴极数码管，44的矩阵式键盘。下面对两种芯片进行说明。1.2.1 单片机STC89C51 单片机的引脚可分为电源、外接晶振、控制和可编程输入/输出引脚。（1）电源引脚（2根） VCC：电源输入，接5V电源GND：接地线（2）外接晶振引脚（2根） XTAL1：片内振荡电路的输入端XTAL2：片内振荡电路的输出端（3）控制引脚（4根） RST：复位引脚，引脚上出现2个机器周期的高电平将使单片机复位。ALE/PROG：地址锁存允许信号/片内EPROM编程脉冲PSEN：外部存储器读选通信号EA/VPP：程序存储器的内外部选通，接低电平从外部程序存储器读指令，如果接高电平

4、则从内部程序存储器读指令。（4）可编程输入/输出引脚（32根） STC89C52单片机有4组8位的可编程I/O口，分别位P0、P1、P2、P3口，每个口有8位（8根引脚），共32根。P0口（P0.0P0.7）：8位双向I/O口线；P1口（P1.0P1.7）：8位准双向I/O口线；P2口（P2.0P2.7）：P3口（P3.0P3.7）：8位准双向I/O口线。1.2.2 AD/DA转换芯片PCF8951PCF8591是单片、单电源低功耗8位CMOS数据采集器件，具有4个模拟输入、一个输出和一个串行I2C总线接口。3个地址引脚A0、A1和A2用于编程硬件地址，允许将最多8个器件连接至I2C总线而不需

5、要额外硬件。器件的地址、控制和数据通过两线双向I2C总线传输。其引脚如下：AIN0AIN3：模拟信号输入端。A0A3：引脚地址端。VDD、VSS：电源端（2.56V）。SDA、SCL：I2C总线的数据线、时钟线。OSC：外部时钟输入端，内部时钟输出端。EXT：内部、外部时钟选择线，使用内部时钟时EXT接地。AGND：模拟信号地。器件功能包括多路复用模拟输入、片上跟踪和保持功能、8位模数转换和8位数模转换。最大转换速率取决于I2C总线的最高速率。具体功能描述如下：（1）地址I2C总线系统中的每一片PCF8591通过发送有效地址到该器件来激活。该地址包括固定部分和可编程部分。可编程部分必须根据地址

6、引脚A0、A1和A2来设置。在I2C总线协议中地址必须是起始条件后作为第一个字节发送。地址字节的最后一位是用于设置以后数据传输方向的读/写位。地址如图1.4所示。（2）控制字发送到 PCF8591 的第二个字节将被存储在控制寄存器，用于控制器件功能。控制寄存器的高半字节用于允许模拟输出，和将模拟输入编程为单端或差分输入。低半字节选择一个由高半字节定义的模拟输入通道。控制字如图1.4所示。（3）D/A转换发送给 PCF8591 的第三个字节被存储到DAC 数据寄存器，并使用片上D/A 转换器转换成对应的模拟电压。这个D/A 转换器由连接至外部参考电压的具有256个接头的电阻分压电路和选择开关组成

7、。接头译码器切换一个接头至DAC 输出线。D/A转换顺序的波形如图1.5。1.3 程序设计及流程图本次优秀的设计为当输入任意频率，数码管显示出频率并输出相应频率的方波，此次设计是由定时时间决定，频率范围为30Hz500Hz，当由按键输入次频率范围内任意频率时，对应数码管显示出来并在示波器上输出方波，流程图如图1.6所示。程序见附录。2 课程设计工作记录2.1 设计步骤和时间安排6月17日至6月18日，选课题，查阅资料。6月19日至6月21日，研究电路图。6月22日至7月1日，根据课题要求，编写程序，从及格开始，然后中，良，优秀依次展开。并进行仿真，纠正程序的功能错误，不断完善程序。7月2日，进

8、行答辩。7月4日，交实习报告。2.2 课题完成结果说明（1）此次简易波形发生器实现了以下功能： 及格：上电之后，数码管最后四位将显示1234，当按键1按下时，显示1234灭亮闪烁一次，时间间隔为0.5s；当按键2按下时，显示1234灭亮闪烁两次，当按键3按下时，显示1234灭亮闪烁三次；当按键4按下时，显示1234灭亮闪烁四次。 中等：上电之后，示波器显示100Hz方波，数码管显示频率100。当有“频率加”按键按下时，频率加100Hz；当有“频率减”按键按下时，频率减100Hz；当有“幅值加”按键按下时，幅值加0.1V；当由“幅值减”按键按下时，幅值减0.1V。 良好：上电之后，数码管无显示，

9、示波器无波形。当有按键1按下时，示波器出现方波，数码管显示对应频率，此时若有频率加减按键按下，方波频率加减100Hz,若有幅值加减按键按下时，方波幅值加减0.1V；当有按键2按下时，示波器出现三角波，数码管显示对应频率，此时若有频率加减按键按下，三角波频率加减100Hz；当有按键3按下时，示波器出现正弦波，数码管显示对应频率，此时若有频率加减按键按下，正弦波频率加减100Hz。 优秀：上电之后示波器无波形，数码无显示，当输入030Hz500Hz内的任意频率后，数码管显示所输频率，示波器显示相应频率的波形。、 （2）实验中遇到的问题： 1.由于是用I2C总线串行输入数据，延时时间较长，定时时间不

10、准确，方波频率显示只能到700Hz，三角波和正弦波频率只能显示到400Hz。 2.由于显示部分占用了延时时间，为了增大频率，将显示部分的延时减小里许多，导致了数码管后两位显示较暗。 3.由于定时不是很准确，优秀中的各个频率所输出的波形也不是特别精确。 （3）总结通过这三周的实习，感觉时间很紧迫，我认为想要真正做好一次设计三周的时间真的不够用，觉得还有很多不足的地方需要改进，但却已经没有时间。在之前学习单片机感觉还能驾驭，即使在平时实验中也还能凑合应付。但当自己真正做一个模块时，有种无从下手的感觉。并且这次设计我们用的是C语言编程，对于单片机的C语言编程我们还不太了解，后来通过去图书馆借书和查阅

11、资料慢慢的了解了许多C语言程序，之后便开始研究电路图并开始编程，刚开始比较困难，问题很多，但在不断的失败和解决问题的过程中，我一点点进步，最终完成了这次设计任务。这次课程实习是我受益匪浅，让我对单片机的原理和功能有了进一步的了解，学到了更多的电路知识，在对单片机编程过程中，认识了解了IIC总线输入方式，了解了PCF8591类芯片的使用方法。从这次实习，我也发现了自己的许多不足，并更加完善了自我，锻炼了动手能力，而且学会了将理论知识和实际相结合。课程设计验收指导教师评语及成绩：成绩指导教师签字年 月 日教研室主任意见教研室主任签字附录简易波形发生器优秀设计程序：#includestdio.hst

12、ring.hintrins.h #define uint unsigned int /宏定义#define uchar unsigned charsbit SCL=P20; /时钟位sbit SDA=P21; /数据位sbit dula=P26; /数码管段选锁存端sbit wela=P27; /数码管位选锁存端uchar code duanma=0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,0x07,0x7f,0x6f; /数码管段码uchar code weima=0xdf,0xbf,0x7f;uchar code plth_tab=0xc4,0xc6,0xc8,0

13、xca,0xcc,0xce,0xcf,0xd1,0xd2,0xd3,0xd4,0xd6,0xd7,0xd8,0xd9,0xda,0xdb,0xdb,0xdc,0xdd,0xde,0xdf,0xdf,0xe0,0xe0,0xe1,0xe2,0xe3,0xe3,0xe4,0xe4,0xe5,0xe5,0xe6,0xe6,0xe7,0xe7,0xe7,0xe8,0xe8,0xe9,0xe9,0xe9,0xea,0xea,0xea,0xeb,0xeb,0xeb,0xeb,0xec,0xec,0xec,0xed,0xed,0xed,0xee,0xee,0xee,0xee,0xee,0xef,0xef,0

14、xef,0xef,0xf0,0xf0,0xf0,0xf0,0xf0,0xf1,0xf1,0xf1,0xf1,0xf1,0xf1,0xf2,0xf2,0xf2,0xf2,0xf2,0xf2,0xf3,0xf3,0xf3,0xf3,0xf3,0xf3,0xf4,0xf4,0xf4,0xf4,0xf4,0xf4,0xf4,0xf4,0xf5,0xf5,0xf5,0xf5,0xf5,0xf5,0xf5,0xf5,0xf5,0xf6,0xf6,0xf6,0xf6,0xf6,0xf6,0xf6,0xf6,0xf6,0xf6,0xf6,0xf7,0xf7,0xf7,0xf7,0xf7,0xf7,0xf7,0

15、xf7,0xf7,0xf7,0xf7,0xf7,0xf7,0xf8,0xf8,0xf8,0xf8,0xf8,0xf8,0xf8,0xf8,0xf8,0xf8,0xf8,0xf8,0xf8,0xf8,0xf9,0xf9,0xf9,0xf9,0xf9,0xf9,0xf9,0xf9,0xf9,0xf9,0xf9,0xf9,0xf9,0xf9,0xf9,0xf9,0xf9,0xf9,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0xfa,0

16、xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfb,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0xfc,0

17、xfc,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfd,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0

18、xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xfe,0xff,0xff,0xff,0xff,0

19、xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0

20、xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff,0xff;uchar code pltl_tab=0xf0,0xf0,0xf0,0xf0,0xe0,0x20,0xf0,0x00,0

21、x20,0x40,0xf0,0x50,0x50,0x60,0x30,0x20,0x00,0xf0,0x90,0x40,0x20,0x00,0xa0,0x1a,0x50,0xd0,0x60,0x20,0xb0,0x05,0x95,0x25,0xb5,0x15,0xa5,0x05,0x95,0xf5,0x4a,0xaa,0x0a,0x6a,0xca,0x20,0x80,0xe0,0x0a,0x6a,0xca,0xfa,0x5a,0xba,0xea,0x4a,0x7a,0xaa,0x0a,0x3a,0x6a,0xca,0xfa,0x2a,0x5a,0x8a,0xea,0x1a,0x4a,0x7a,0

22、xaa,0xda,0x0a,0x3a,0x60,0x90,0xc0,0xf0,0x20,0x55,0x7f,0x9f,0xcf,0xf0,0x3f,0x6f,0x87,0x9f,0xcf,0xed,0x0b,0x2a,0x5a,0x72,0x8a,0xba,0xd2,0xea,0x15,0x2d,0x45,0x5d,0x75,0xa5,0xbd,0xd5,0xeb,0x00,0x18,0x30,0x48,0x60,0x78,0x90,0xa8,0xc0,0xd8,0xf0,0x04,0x18,0x30,0x48,0x60,0x78,0x88,0x98,0xa8,0xc0,0xd8,0xe8,0

23、xf8,0x08,0x20,0x38,0x45,0x52,0x60,0x78,0x90,0xa0,0xb0,0xc0,0xd0,0xe0,0xf0,0x00,0x10,0x20,0x30,0x40,0x50,0x5c,0x69,0x75,0x80,0x90,0xa0,0xb0,0xbc,0xc9,0xd5,0xe0,0xf0,0x00,0x10,0x1c,0x29,0x35,0x40,0x4c,0x59,0x65,0x70,0x7c,0x89,0x95,0xa0,0xac,0xb9,0xc5,0xd0,0xda,0xe3,0xed,0xf6,0x00,0x0d,0x1a,0x27,0x35,0

24、x40,0x4a,0x55,0x5f,0x6a,0x74,0x7d,0x87,0x90,0x9a,0xa4,0xad,0xb7,0xc0,0xca,0xd2,0xda,0xe2,0xea,0xf2,0xfa,0x02,0x0a,0x12,0x1a,0x22,0x2a,0x32,0x3a,0x42,0x4a,0x52,0x5a,0x62,0x6a,0x72,0x7a,0x82,0x8a,0x91,0x98,0x9e,0xa5,0xac,0xb3,0xba,0xc1,0xc8,0xce,0xd5,0xdc,0xd3,0xea,0xf0,0xf6,0xfc,0x02,0x08,0x0e,0x14,0

25、x1a,0x20,0x26,0x2c,0x32,0x38,0x3e,0x44,0x4a,0x50,0x56,0x5c,0x62,0x68,0x6e,0x74,0x7a,0x80,0x85,0x8a,0x8f,0x94,0x9a,0x9f,0xa4,0xaa,0xb0,0xb5,0xba,0xc0,0xc5,0xca,0xcf,0xd4,0xda,0xdf,0xe4,0xe8,0xed,0xf2,0xf6,0xfb,0x00,0x05,0x0a,0x0f,0x13,0x17,0x1b,0x20,0x24,0x28,0x2c,0x30,0x35,0x3a,0x3e,0x41,0x44,0x48,0

26、x4b,0x4e,0x52,0x56,0x5a,0x5d,0x61,0x65,0x69,0x6c,0x6f,0x72,0x76,0x79,0x7d,0x80,0x83,0x86,0x8a,0x8e,0x93,0x97,0x9b,0x9f,0xa3,0xa8,0xac,0xb0,0xb4,0xb8,0xbc,0xc0,0xc5,0xc9,0xcc,0xcf,0xd2,0xd5,0xd8,0xdc,0xdf,0xe2,0xe5,0xe8,0xeb,0xee,0xf1,0xf5,0xf8,0xfb,0xfe,0x01,0x03,0x06,0x08,0x0b,0x0e,0x10,0x13,0x15,0

27、x18,0x1b,0x20,0x23,0x25,0x28,0x2b,0x2d,0x30,0x32,0x35,0x37,0x3a,0x3d,0x3f,0x42,0x44,0x47,0x4a,0x4f,0x52,0x55,0x58,0x5b,0x5f,0x62,0x64,0x68,0x6a,0x6d,0x70,0x73,0x76,0x79,0x7b,0x7d,0x80,0x82,0x85,0x88,0x8a,0x8c,0x8e,0x91,0x93,0x96,0x99,0x9b,0x9d,0x9f,0xa3,0xa6,0xa8,0xaa,0xad,0xae,0xb0,0xb2,0xb4,0xb6,0

28、xb8,0xba,0xbc,0xbe,0xbf,0xc1,0xc3,0xc5,0xc6,0xc8,0xca,0xcc,0xce,0xd0,0xd2,0xd4,0xd6,0xd8,0xda,0xdc,0xdd,0xdf,0xe0,0xe2,0xe3,0xe4,0xe6,0xe8,0xe9,0xea,0xec,0xee,0xf0,0xf2,0xf4,0xf5,0xf6,0xf8,0xfa,0xfb,0xfc,0xfe,0xff;uchar code fz_tab=0x05,0x0a,0x0f,0x14,0x1a,0x1f,0x24,0x29,0x2e,0x33,0x38,0x3d,0x43,0x4

29、8,0x4d,0x52,0x57,0x5c,0x61,0x66,0x6c,0x71,0x76,0x7b,0x80,0x85,0x8a,0x8f,0x94,0x9a,0x9f,0xa4,0xa9,0xae,0xb3,0xb8,0xbd,0xc3,0xc8,0xcd,0xd2,0xd7,0xdc,0xe1,0xe6,0xeb,0xf0,0xf5,0xfa,0xff; /方波幅值void delay（uchar i）;void delayNOP（）;void display（）;void iic_start（）;void iic_Init（）;void check_ack（）;void iic_sendbyte（uchar indata）;void DAC_fang