- 1 基本原理
- 1.1 寄存器介绍
- 1.2 寄存器汇总
- 1.3 ADC采集实现框图
- 2 实现代码
// PIC16F15323 Configuration Bit Settings // 'C' source line config statements // CONFIG1 #pragma config FEXTOSC = ECH // External Oscillator mode selection bits (EC above 8MHz; PFM set to high power) #pragma config RSTOSC = EXT1X // Power-up default value for COSC bits (EXTOSC operating per FEXTOSC bits) #pragma config CLKOUTEN = OFF // Clock Out Enable bit (CLKOUT function is disabled; i/o or oscillator function on OSC2) #pragma config CSWEN = ON // Clock Switch Enable bit (Writing to NOSC and NDIV is allowed) #pragma config FCMEN = ON // Fail-Safe Clock Monitor Enable bit (FSCM timer enabled) // CONFIG2 #pragma config MCLRE = ON // Master Clear Enable bit (MCLR pin is Master Clear function) #pragma config PWRTE = OFF // Power-up Timer Enable bit (PWRT disabled) #pragma config LPBOREN = OFF // Low-Power BOR enable bit (ULPBOR disabled) #pragma config BOREN = ON // Brown-out reset enable bits (Brown-out Reset Enabled, SBOREN bit is ignored) #pragma config BORV = LO // Brown-out Reset Voltage Selection (Brown-out Reset Voltage (VBOR) set to 1.9V on LF, and 2.45V on F Devices) #pragma config ZCD = OFF // Zero-cross detect disable (Zero-cross detect circuit is disabled at POR.) #pragma config PPS1WAY = ON // Peripheral Pin Select one-way control (The PPSLOCK bit can be cleared and set only once in software) #pragma config STVREN = ON // Stack Overflow/Underflow Reset Enable bit (Stack Overflow or Underflow will cause a reset) // CONFIG3 #pragma config WDTCPS = WDTCPS_31// WDT Period Select bits (Divider ratio 1:65536; software control of WDTPS) #pragma config WDTE = ON // WDT operating mode (WDT enabled regardless of sleep; SWDTEN ignored) #pragma config WDTCWS = WDTCWS_7// WDT Window Select bits (window always open (100%); software control; keyed access not required) #pragma config WDTCCS = SC // WDT input clock selector (Software Control) // CONFIG4 #pragma config BBSIZE = BB512 // Boot Block Size Selection bits (512 words boot block size) #pragma config BBEN = OFF // Boot Block Enable bit (Boot Block disabled) #pragma config SAFEN = OFF // SAF Enable bit (SAF disabled) #pragma config WRTAPP = OFF // Application Block Write Protection bit (Application Block not write protected) #pragma config WRTB = OFF // Boot Block Write Protection bit (Boot Block not write protected) #pragma config WRTC = OFF // Configuration Register Write Protection bit (Configuration Register not write protected) #pragma config WRTSAF = OFF // Storage Area Flash Write Protection bit (SAF not write protected) #pragma config LVP = ON // Low Voltage Programming Enable bit (Low Voltage programming enabled. MCLR/Vpp pin function is MCLR.) // CONFIG5 #pragma config CP = OFF // UserNVM Program memory code protection bit (UserNVM code protection disabled) // #pragma config statements should precede project file includes. // Use project enums instead of #define for ON and OFF. #include// 调用PIC16f15323单片机的头文件 //#include"delay.h"//调用延时子函数的头文件 #define uint unsigned int #define uchar unsigned char uint ADbuf=0; // 缓存AD转换结果 void main() { //-------------------1、Configure Port:---------------------// // The corresponding data direction register is TRISA. // Setting a TRISA bit (= 1) will make the corresponding PORTA pi an input. // Clearing a TRISA bit (= 0) will make the corresponding PORTA pin an output. // 解释为什么需要TRISA0=1？ After the A/D module has been configured as desired, // the selected channel must be acquired before the conversion is started. // The analog input channels must have their corresponding TRIS bits selected as inputs. TRISA0=1; // RA0口为输入口，电压输入口 TRISC0=0; // AD响应中断对应的LED灯的数据方向为输出 // 1 = Port pin is > VIH，即高电平 ; 0 = Port pin is < VIL，即低电平 RA0=0; // 要不要这行语句没有影响，因为该端口是输入端口 RC0=0; // LED灯的初值为灭 //The ANSELA register (Register 14-4) is used to configure the Input mode of an I/O pin to analog. // Setting the appropriate ANSE 如果ANSEL=1，IO口为模拟输入，如果ANSEL=0，数字IO口。 ANSA0=1; // Set RA0 to analog ANSELA0,为什么见头文件 while(1) // 死循环，单片机初始化后，就一直运行这个死循环 { //-------------------2、Configure the ADC module:---------------------// //（1）寄存器ADCON1: ADFM ADCS<2:0> - - ADPREF<1:0> // 10-BIT ADC ConVERSION RESULT FORMAT ADFM=1; // AD Result Format Select bit. 0 = Left justified. 1 = Right justified //The source of the conversion clock is software selectable via the ADCS<2:0> bits ADCS2=0;ADCS1=0;ADCS0=0; // Select ADC conversion clock FOSC/2 // The ADPREF<1:0> bits of the ADCON1 register provides control of the positive voltage reference ADPREF1=0;ADPREF0=0; // Select voltage reference 00 =VREF+ is connected to VDD //（2）寄存器ADCON0: CHS<5:0> GO/DONE ADON //The CHS<5:0> bits of the ADCON0 register determine which channel is connected to the sample and hold circuit. //CHS5=1;CHS4=1;CHS3=1;CHS2=1;CHS1=0;CHS0=0; // Select ADC input channel Temperature sensor 选择温度传感器作为模拟输入 CHS5=0;CHS4=0;CHS3=0;CHS2=0;CHS1=0;CHS0=0; // Select ADC input channel 选择RA0(AN0)作为模拟输入 //ADC Conversion Status bit. 1 = ADC conversion cycle in progress. Setting this bit starts an ADC conversion cycle. // This bit is automatically cleared by hardware when the ADC conversion has completed. // 0 = ADC conversion completed/not in progress GOnDONE=0; // AD Conversion Status bit。为什么叫用GO_DONE看一下xc.h头文件 //To enable the ADC module, the ADON bit of the ADCON0 register must be set to a ‘1’. ADON=1; //Turn on ADC module 模数转换器使能位。 1 = A/D converter module is powered up //--------------------3、Configure ADC interrupt (optional):---------------------// //ADIE=0; //禁止AD中断 //AD中断使能 ADIE=1; ADIF=0; // Clear ADIF bit INTEDG=1; // Interrupt Edge Select bit 1 = Interrupt on rising edge of INT pin PEIE=1; // 允许外设中断 GIE=1; // 总中断允许 //----------ADC BLOCK DIAGRAM框图有下面两个寄存器，但是AD采集程序没有用到？--------------// // AUTO ConVERSION TRIGGER // TRIGSEL<3:0>; //The Auto-conversion Trigger source is selected with the ADACT<4:0> bits of the ADACT register. ADACT4=0;ADACT3=0;ADACT2=0;ADACT1=0;ADACT0=0;//Auto-Conversion Trigger Selection bits //--------------------4、 Wait the required acquisition time:---------------------// asm("NOP"); //延时，让模拟电压稳定 asm("NOP"); asm("NOP"); asm("NOP"); asm("NOP"); //---------------5、Start conversion by setting the GO/DONE bit.:---------------------// // When ADON = 1时，GO_DONE=1: AD conversion in progress set this bit（GO_DONE=1）, starts the AD conversion. // it is automatically cleared by hardware when the AD conversion is complete GOnDONE=1; //开始进行AD转换 GO/DONE: A/D Conversion Status bit ADGO=1; //---------6、Wait for ADC conversion to complete by one ofthe following:（1）Polling the GO/DONE bit。（2）Waiting for the ADC interrupt------// while( GOnDONE) continue;//等待AD转换结束，AD转换完成后，GO_DONE自动由1变成0 //-----------------------7、Read ADC Result----------------------// // The conversion of an analog input signal results in a corresponding 10-bit digital number. // The ADRESH（高8位）:ADRESL（低8位） registers contain the 10-bit result of the AD conversion. // When the AD conversion is complete, the result is loaded into this AD Result register pair, // and the GO/DONE bit is cleared and the A/D interrupt flag bit ADIF is set // 需要注意到底是左对齐还是右对齐，这会影响ADbuf=ADRESH*256+ADRESL是否正确 ADbuf=ADRESH*256+ADRESL;//转换结果一共有10bit。由于2^10为1024，所以这是一个4位数 0-1023 //---------------8、Clear the ADC interrupt flag (required if interrupt is enabled)--------------------// } } // void __interrupt(irq(TMR0,TMR1),base(0x100)) timerIsr(void) // 文档里可以查到要用 void __interrupt() ISR(void) 的形式添加中断程序 //void interrupt ISR(void)//PIC单片机的所有中断都是这样一个入口 void __interrupt() ISR(void)//PIC单片机的所有中断都是这样一个入口 { // When the AD conversion is complete, the A/D interrupt flag bit ADIF is set. if(ADIF==1) // 需要进一步判断是否为外部中断的溢出中断标志位 { // The interrupt flag bit(s) must be cleared in software before // re-enabling interrupts to avoid recursive interrupts //溢出中断标志位清零 如果ADIF出现上升沿，则产生中断，所以中断发生之后要清零。 ADIF=0; // 执行中断处理程序，执行中断产生时想要执行的功能 RC0=1; // 外部中断发生时，LED灯亮 } }
