一 STC32G单片机内置ADC模块简介

STC32G单片机内部集成了一个12位高速ADC转换器，ADC的最高时钟频率为系统频率的1/2。其输入通道多达15个（第15通道为专门测量内部1.19V参考信号源的通道），可分时切换使用。

STC15系列单片机内置ADC模块以电源电源作为ADC参考电压，STC32G的ADC模块则与之不同，它有单独的参考电压源引脚，可以接入精准的参考电压（0~5V皆可），以获得稳定的ADC值；参考电源引脚也可直接与MCU供电电源连接，不过AD转换结果可能会收到电源电源波动的影响。注意：STC32GADC模块的参考电压输入引脚不可悬空。

STC32G单片机的内置ADC模块转换结果存储在两个8位寄存器中，可配置为左对齐（高8位存储在高位寄存器ADC_RES中，低四位存储在低位寄存器ADC_REL的高四位中），可配置为右对齐（高4位存储在高位寄存器ADC_RES的低4位中，低8位存储在低位寄存器ADC_REL中）。

二 STC32G单片机内置ADC模块的相关寄存器

STC32G单片机内置ADC模块的相关寄存器包含控制寄存器ADC_CONTR、转换结果高位寄存器ADC_RES、转换结果低位寄存器ADC_RESL、配置寄存器ADCCFG、时序控制寄存器ADCTIM。下面是STC用户手册对这几个寄存器的功能介绍。

寄存器ADC_CONTR

配置寄存器ADCCFG

时序控制寄存器ADCTIM

三 ADC模块函数库编程

ADC模块应用离不开相关寄存器编程，先将常用的寄存器配置操作编写成库函数供以后调用。

头文件

/*STC32G_ADC.hDesigned by Bill LiuVersion 0.0 Modified last by Bill Liu,7/21//enum//STC32G_ADC_CHN //STC32G ADC channelSTC32G_ADC_SPEED //STC32G ADC clock frequency/Macro functionSTC32G_ADCPOWERON(); //adc power onSTC32G_ADCPOWEROFF(); //adc power offSTC32G_ADCSTART();//adc startSTC32G_ADCSTOP(); //adc stopSTC32G_ADCCLEARFLAG()://clear flagSTC32G_ADCPWMTRIENBLE(); //PWM trigger adc enableSTC32G_ADCPWMTRIDISBLE();//PWM trigger adc disableSTC32G_ADCSELCH0(); //selected ADC_CH0STC32G_ADCSELCH1(); //selected ADC_CH1STC32G_ADCSELCH2(); //selected ADC_CH2STC32G_ADCSELCH3(); //selected ADC_CH3STC32G_ADCSELCH4(); //selected ADC_CH4STC32G_ADCSELCH5(); //selected ADC_CH5STC32G_ADCSELCH6(); //selected ADC_CH6STC32G_ADCSELCH7(); //selected ADC_CH7STC32G_ADCSELCH8(); //selected ADC_CH8STC32G_ADCSELCH9(); //selected ADC_CH9STC32G_ADCSELCH10(); //selected ADC_CH10STC32G_ADCSELCH11(); //selected ADC_CH11STC32G_ADCSELCH12(); //selected ADC_CH12STC32G_ADCSELCH13(); //selected ADC_CH13STC32G_ADCSELCH14(); //selected ADC_CH14STC32G_ADCSELCH15();//selected ADC_CH15 at inner band gap voltageSTC32G_ADCRESLALIG();//adc result left alignmentSTC32G_ADCRESRALIG(): //adc result right alignment//fuanction/STC32G_AdcSelChn(STC32G_ADC_CHN chn); //return voidSTC32G_AdcSelSpeed(STC32G_ADC_SPEED selSpeed); //return voidSTC32G_AdcStructInitDef(STC32G_ADC_TypeDef* pStruct); //return voidSTC32G_AdcInit(STC32G_ADC_TypeDef mStruct); //return voidSTC32G_AdcGetRes(ui16* pResult); //return ui16*/#ifndef__STC32G_ADC_H#define__STC32G_ADC_H#include"config.h"#include "STC32G_GPIO.h"#define STC32G_ADCPOWERON(){ADC_POWER = 1;} //adc power on#define STC32G_ADCPOWEROFF() {ADC_POWER = 0;} //adc power off#define STC32G_ADCSTART() {ADC_START = 1;} //adc start#define STC32G_ADCSTOP() {ADC_START = 0;}//adc stop#define STC32G_ADCCLEARFLAG() {ADC_FLAG = 0;} //clear flag#define STC32G_ADCPWMTRIENBLe(){ADC_EPWMT = 1;} //PWM trigger adc enable#define STC32G_ADCPWMTRIDISBLE(){ADC_EPWMT = 0;}//PWM trigger adc disable#define STC32G_ADCSELCH0() {STC32G_P1MODE_HIIN(PIN0); ADC_CONTR &= 0xF0;} //selected ADC_CH0#define STC32G_ADCSELCH1() {STC32G_P1MODE_HIIN(PIN1); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x01;} //selected ADC_CH1#define STC32G_ADCSELCH2() {STC32G_P1MODE_HIIN(PIN2); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x02;} //selected ADC_CH2#define STC32G_ADCSELCH3() {STC32G_P1MODE_HIIN(PIN3); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x03;} //selected ADC_CH3#define STC32G_ADCSELCH4() {STC32G_P1MODE_HIIN(PIN4); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x04;} //selected ADC_CH4#define STC32G_ADCSELCH5() {STC32G_P1MODE_HIIN(PIN5); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x05;} //selected ADC_CH5#define STC32G_ADCSELCH6() {STC32G_P1MODE_HIIN(PIN6); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x06;} //selected ADC_CH6#define STC32G_ADCSELCH7() {STC32G_P1MODE_HIIN(PIN7); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x07;} //selected ADC_CH7#define STC32G_ADCSELCH8() {STC32G_P0MODE_HIIN(PIN0); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x08;} //selected ADC_CH8#define STC32G_ADCSELCH9() {STC32G_P0MODE_HIIN(PIN1); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x09;} //selected ADC_CH9#define STC32G_ADCSELCH10() {STC32G_P0MODE_HIIN(PIN2); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x10;} //selected ADC_CH10#define STC32G_ADCSELCH11() {STC32G_P0MODE_HIIN(PIN3); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x11;} //selected ADC_CH11#define STC32G_ADCSELCH12() {STC32G_P0MODE_HIIN(PIN4); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x12;} //selected ADC_CH12#define STC32G_ADCSELCH13() {STC32G_P0MODE_HIIN(PIN5); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x13;} //selected ADC_CH13#define STC32G_ADCSELCH14() {STC32G_P0MODE_HIIN(PIN6); ADC_CONTR &= 0xF0; ADC_CONTR |= 0x14;} //selected ADC_CH14#define STC32G_ADCSELCH15() { ADC_CONTR &= 0xF0; ADC_CONTR |= 0x15;} //selected band gap voltage#define STC32G_ADCRESLALIG() {RESFMT = 0;} //adc result left alignment#define STC32G_ADCRESRALIG() {RESFMT = 1;} //adc result right alignment//******************************************************typedef enum{ADC_CH0 =0, //ADC channel 0 at P10ADC_CH1, //ADC channel 1 at P11ADC_CH2, //ADC channel 2 at P54ADC_CH3, //ADC channel 3 at P13ADC_CH4, //ADC channel 4 at P14ADC_CH5, //ADC channel 5 at P15ADC_CH6, //ADC channel 6 at P16ADC_CH7, //ADC channel 7 at P17ADC_CH8, //ADC channel 8 at P00ADC_CH9, //ADC channel 9 at P01ADC_CH10, //ADC channel 10 at P02ADC_CH11, //ADC channel 11 at P03ADC_CH12, //ADC channel 12 at P04ADC_CH13, //ADC channel 13 at P05ADC_CH14, //ADC channel 14 at P06ADC_CH15, //ADC channel 15 at inner band gap voltage}STC32G_ADC_CHN; //STC32G ADC channel//******************************************************typedef enum{FOSC_DIV_2X1 = 0, // FOSC / (2 * 1)FOSC_DIV_2X2,// FOSC / (2 * 2)FOSC_DIV_2X3,// FOSC / (2 * 3)FOSC_DIV_2X4,// FOSC / (2 * 4)FOSC_DIV_2X5,// FOSC / (2 * 5)FOSC_DIV_2X6,// FOSC / (2 * 6)FOSC_DIV_2X7,// FOSC / (2 * 7)FOSC_DIV_2X8,// FOSC / (2 * 8)FOSC_DIV_2X9,// FOSC / (2 * 9)FOSC_DIV_2X10,// FOSC / (2 * 10)FOSC_DIV_2X11,// FOSC / (2 * 11)FOSC_DIV_2X12,// FOSC / (2 * 12)FOSC_DIV_2X13,// FOSC / (2 * 13)FOSC_DIV_2X14,// FOSC / (2 * 14)FOSC_DIV_2X15,// FOSC / (2 * 15)FOSC_DIV_2X16,// FOSC / (2 * 16)}STC32G_ADC_SPEED; //STC32G ADC clock frequency//******************************************************typedef struct{BOOL adcPowerOn;//ADC power on enable/disable, 0-disable, 1-enable STC32G_ADC_CHN adcChn; //slected adc channelBOOL pwmTrigAble;STC32G_ADC_SPEED adcSpeed;//STC32G_ADC_SPEEDBOOLadcResultRA;//adc result_data style,0:left alignment(default), 1:right alignmentBOOLadcSetupTime;//ADC channel select setup time control congigure, 0: 1 system clock cycles(default), 1: 2 system clock cyclesu8adcHoldTime;//ADC channel select hold time control congigure. 0: 1 ADC clock cycle time, 1:2 ADC clock cycle timesu8adcSampleTime;//analog signal sampling control time. 10 min. recommended 0x1F}STC32G_ADC_TypeDef;/******************************************************Function: STC32G_AdcSelChn(STC32G_ADC_CHN chn);return value: voidchn:adc channeldescription: select adc channelExample:STC32G_AdcSelChn(ADC_CH0);******************************************************/void STC32G_AdcSelChn(STC32G_ADC_CHN chn);/******************************************************Function: STC32G_AdcSelSpeed(STC32G_ADC_SPEED selSpeed);return value: voidselSpeed:selected speeddescription: configure adc speedExample:STC32G_AdcSelSpeed(FOSC_DIV_2X16);******************************************************/void STC32G_AdcSelSpeed(STC32G_ADC_SPEED selSpeed);/******************************************************Function: STC32G_AdcInitDef(STC32G_ADC_TypeDef* pStruct);return value: voidpStruct: STC32G_ADC_TypeDef struct address to be inited to defaultdescription: Init STC32G_ADC_TypeDef struct to default valueExample:STC32G_ADC_TypeDef mStruct;STC32G_AdcInitDef(&mStruct);******************************************************/void STC32G_AdcInitDef(STC32G_ADC_TypeDef* pStruct);/******************************************************Function: STC32G_AdcInit(STC32G_ADC_TypeDef mStruct);return value: voidmStruct: configure STC32G by mStructdescription: init adcExample:STC32G_ADC_TypeDef mStruct;STC32G_AdcInit(mStruct);******************************************************/void STC32G_AdcInit(STC32G_ADC_TypeDef mStruct);/******************************************************Function: STC32G_AdcGetRes(ui16* pResult);return value: ui16pResult: address to store got resultdescription: get adc resultExample:ui16 mReult;STC32G_AdcGetRes(&mReult);******************************************************/u16 STC32G_AdcGetRes(ui16* pResult);#endif

源文件

/*STC32G_ADC.cDesigned by Bill LiuVersion 0.0 Modified last by Bill Liu, 07/21/*/#include"STC32G_ADC.h"//******************************************************void STC32G_AdcSelChn(STC32G_ADC_CHN chn){switch(chn){case ADC_CH0:STC32G_ADCSELCH0()break;case ADC_CH1:STC32G_ADCSELCH1()break;case ADC_CH2:STC32G_ADCSELCH2()break;case ADC_CH3:STC32G_ADCSELCH3()break;case ADC_CH4:STC32G_ADCSELCH4()break;case ADC_CH5:STC32G_ADCSELCH5()break;case ADC_CH6:STC32G_ADCSELCH6()break;case ADC_CH7:STC32G_ADCSELCH7()break;case ADC_CH8:STC32G_ADCSELCH8()break;case ADC_CH9:STC32G_ADCSELCH9()break;case ADC_CH10:STC32G_ADCSELCH10()break;case ADC_CH11:STC32G_ADCSELCH11()break;case ADC_CH12:STC32G_ADCSELCH12()break;case ADC_CH13:STC32G_ADCSELCH13()break;case ADC_CH14:STC32G_ADCSELCH14()break;case ADC_CH15:STC32G_ADCSELCH15()break;}}//End of STC32G_AdcSelChn(STC32G_ADC_CHN chn)//******************************************************void STC32G_AdcSelSpeed(STC32G_ADC_SPEED selSpeed){ADCCFG &= 0xF0;ADCCFG |= selSpeed;}//End of STC32G_AdcSelSpeed(STC32G_ADC_SPEED selSpeed)//******************************************************void STC32G_AdcInitDef(STC32G_ADC_TypeDef* pStruct){pStruct -> adcPowerOn = 0;pStruct -> adcChn = ADC_CH0;pStruct -> pwmTrigAble = 0; //PWM trigger disablepStruct -> adcSpeed = FOSC_DIV_2X1; //adc clk is sclok/2pStruct -> adcResultRA = 0; //adc result left alignpStruct -> adcSetupTime = 0; //Tadcsetup a adc clkpStruct -> adcHoldTime = 0x01;//adc hold time 2 adc clkpStruct -> adcSampleTime = 0x0A; //adc sampling time: 11 adc clk, 0x0A <= adcSampleTime <= 0x1F }//End of STC32G_AdcInitDef(STC32G_ADC_TypeDef* pStruct)//******************************************************void STC32G_AdcInit(STC32G_ADC_TypeDef mStruct){STC32G_AdcSelChn(mStruct.adcChn);ADC_EPWMT = mStruct.pwmTrigAble;ADCCFG &= 0xF0;ADCCFG |= mStruct.adcSpeed;RESFMT = mStruct.adcResultRA;ADCTIM &= 0x7F;ADCTIM |= mStruct.adcSetupTime;ADCTIM &= 0x9F;ADCTIM |= mStruct. adcHoldTime;ADCTIM &= 0xE0;ADCTIM |= mStruct. adcSampleTime;ADC_POWER = mStruct.adcPowerOn;}//End of STC32G_AdcInit(STC32G_ADC_TypeDef mStruct)//******************************************************u16 STC32G_AdcGetRes(ui16* pResult){*pResult = 0;STC32G_ADCSTART();_nop_();_nop_();while(!ADC_FLAG);STC32G_ADCCLEARFLAG()*pResult = ADC_RES;if(RESFMT){*pResult <<= 8;*pResult += ADC_RESL;}else{*pResult <<= 4;*pResult += ADC_RESL >> 4;}return *pResult;}//End of STC32G_AdcGetRes(ui16* pResult)

四 应用编程示例

下面写段示例程序，演示ADC库文件的使用。

头文件：

/*main.hDesigned by Bill LiuVersion 0.0 Modified last by Bill Liu ,04/18/*/#ifndef__MAIN_H__#define__MAIN_H__//#include "myport.h"#include "mtype.h"#include "config.h"#include "STC32G_GPIO.h"#include "STC32G_Delay.h"#include "STC32G_UART.h"//#include "STC32G_EEPROM.h"//#include "STC32G_PWM.h"#include "STC32G_ADC.h"//#include "STC32G_EEPROM.H"//#include "STC32G_SPI.h"//#include "STC32G_PWM.h"//#include "STC32G_Timer.h"//#include "STC32G_comparator.h"STC32G_ADC_TypeDef mstruct;#endif

源文件：

/*main.cDesigned by Bill LiuVersion 0.0 Modified last by Bill Liu, 03/25/*/#include "main.h"ui8 str[30] = {0};ui16 ADCRes = 0;f32 TestVoltage = 0;void main(){SysInit();Uart1_Init(VBAUD_8BITS,G1, 0, 9600);STC32G_AdcInitDef(&mstruct);mstruct.adcPowerOn = 1;mstruct.adcChn = ADC_CH0;mstruct.pwmTrigAble = 0;mstruct.adcSpeed = FOSC_DIV_2X16;mstruct.adcHoldTime = 0x01;mstruct.adcSampleTime = 0x1F;STC32G_AdcInit(mstruct);while(1){STC32G_AdcGetRes(&ADCRes);Uart1_SendString("ADCRes = ");LongToString(ADCRes,str);Uart1_SendString(str);Uart1_SendString("\r\n"); TestVoltage = 5000.0/4096*ADCRes;FloatString(TestVoltage,str,2);Uart1_SendString("TestVoltage = ");Uart1_SendString(str);Uart1_SendString("mV");Uart1_SendString("\r\n");/*STC32G_ADCSELCH15()STC32G_AdcGetRes(&ADCRes);Uart1_SendString("ADCRes = ");LongToString(ADCRes,str);Uart1_SendString(str);Uart1_SendString("\r\n"); TestVoltage = 5000.0/4096*ADCRes;FloatString(TestVoltage,str,2);Uart1_SendString("Inner Bandgap Voltage = ");Uart1_SendString(str);Uart1_SendString("mV");Uart1_SendString("\r\n");STC32G_ADCSELCH0()*/Uart1_SendString("This a ADC Test Program!");Uart1_SendString("\r\n");Uart1_SendString("\r\n");Uart1_SendString("\r\n");Delayxms(1000);}}//End of main()

测试板的参考电压为基准电压芯片AD586提供的5V电压。下面用一个10K的电位器将5V电源电压分压，将分压接到P1.0做AD输入，用ADC来测试分得电压的大小。

测得基准电压值：

测得分压值：

将程序编译，下载到单片机，在串口助手上看到的结果如下：

将源文件中的注释去掉，再获取内部Bandgap的ADC值，并将其转换为电压，结果如下：

从结果可以看出，获得的Bandgap电压并不是手册上所说的1.19V，至于为什么，不是此处讨论的范围。本例已完整演示了，如何调用ADC库函数，实现ADC值获取及如何用ADC测量电压。

相关库函数及示例源代码下载链接：

/download/billliu66/87701680