STM32__ 06 - single channel ADC

One ,ADC（ Analog to digital conversion ）

STM32 Chip integrated 12 Bit successive approximation type ADC modular , What is successive approximation , Simply put, there is a built-in DAC The module is used to output a voltage for binary comparison with the input voltage , adopt DAC To determine the numerical value of the input voltage . The input voltage range is 0~3.3, Corresponding digital quantity 0~4095. I'm using 103c8t6, Yes 2 individual ADC modular , Respectively ADC1 And ADC2, Every ADC Module has 10 Channels . Next is the following ADC The module is briefly introduced .

  I will learn the part of this section , Divide into 3 The modules are

1, Input module

      The input pin is for IO Please refer to the following figure , The pin application diagram is from Jiangke University

 

This picture is very important , It will be used many times later . The configuration of the input module is relatively simple, and it is configured as GPIO_Mode_AIN（GPIO Analog input mode ）

2, Connection channel module

This part mainly configures the input channel , The order , Transformation cycle .

It also involves mode selection ： Injection mode and rule mode

What we are talking about here is the rule pattern , A simple explanation is to sort the input channels , Then according to certain rules, there is a single conversion , Continuous transformation , Scan conversion , Non scan conversion . Refer to the data manual for specific functions .

3,ADC Converter module （ a key ）

In the use of ADC The converter needs to set the prescaler , The prescaler is right 72MHz Divide the internal clock of

  Although it can be /2,/4,/6,/8 frequency division , however ADCCLK The biggest one is 14MHz, So you can only use /6,/8 frequency division .

Trigger source can be timer or software .

After the conversion, the value needs to be read from the register , But the register is 16 position , But the value read is 12 position , It needs to be right here 12 Right align the values of bits .

Two , Code section

Conduct ADC Several steps of , Basically follow the above 3 Programming of large modules

1, Turn on RCC, Include ADC And GPIO

2,GPIO initialization , Configured for analog input mode

3, Configure the connection module

4,ADC converter

5, Turn on ADC

6, calibration , Reduce error

      Calibration does not require in-depth understanding , Just know how to calibrate .

AD.c

#include "stm32f10x.h"                  // Device header

void AD_Init(void)
{
	// Turn on the clock 
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1,ENABLE);// Turn on ADC1 The clock 
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA,ENABLE);// Turn on GPIOA The clock 
	
	
	
	GPIO_InitTypeDef GPIO_InitStructure;
	GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AIN;
	GPIO_InitStructure.GPIO_Pin=GPIO_Pin_0;
	GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
	GPIO_Init(GPIOA,&GPIO_InitStructure);
	
	ADC_RegularChannelConfig(ADC1,ADC_Channel_0,1,ADC_SampleTime_55Cycles5);// Select the input channel of the rule group 
	
  // initialization ADC
	ADC_InitTypeDef ADC_InitStructure;
	ADC_InitStructure.ADC_Mode=ADC_Mode_Independent;// Select independent working mode 
	ADC_InitStructure.ADC_DataAlign=ADC_DataAlign_Right;// Data alignment ： Right alignment 
	ADC_InitStructure.ADC_ExternalTrigConv=ADC_ExternalTrigConv_None;// External trigger source selects software trigger 
	ADC_InitStructure.ADC_ContinuousConvMode=DISABLE;// Continuous conversion mode or single mode 
	ADC_InitStructure.ADC_ScanConvMode=DISABLE;//	 Scan mode or non scan mode 
	ADC_InitStructure.ADC_NbrOfChannel=1;// Number of channels 1~16;
	ADC_Init(ADC1,&ADC_InitStructure);
	RCC_ADCCLKConfig(RCC_PCLK2_Div6);// To configure ADCCLK  6 frequency division   72/6=12MHz
	// Turn on ADC
	ADC_Cmd(ADC1,ENABLE);
	
	// calibration 
	ADC_ResetCalibration(ADC1);// Reset calibration 
	while(ADC_GetResetCalibrationStatus(ADC1)==SET);// Wait for reset calibration to complete 
	ADC_StartCalibration(ADC1);// Start calibration 
	while(ADC_GetCalibrationStatus(ADC1)==SET);// Wait for the calibration to complete 
	
}

uint16_t AD_GetValue(void)
{
	ADC_SoftwareStartConvCmd(ADC1,ENABLE);
	while(ADC_GetFlagStatus(ADC1,ADC_FLAG_EOC)==RESET);// Rule group or injection group conversion completion flag bit 
	return ADC_GetConversionValue(ADC1);
}

main.c

#include "stm32f10x.h"                  // Device header
#include "Delay.h"
#include "LED.h"
#include "Key.h"
#include "Buzzer.h"
#include "OLED.h "
#include "AD.h"

uint16_t ADValue;
float Volatge;
int main()
{
   OLED_Init();
	 AD_Init();
	 
	OLED_ShowString(1,1,"ADValue");
	OLED_ShowString(2,1,"Volatge:0.00V");
	while(1)
	{
    ADValue = AD_GetValue();		
		Volatge = (float)ADValue / 1241;
		
		OLED_ShowNum(1,9,ADValue,4);
		OLED_ShowNum(2,9,Volatge,1);// Show the part of an integer 
		OLED_ShowNum(2,11,(uint16_t)(Volatge*100)%100,2);
		Delay_ms(100);
	}
	
}

3、 ... and , summary

32 It's a little entry , It's a lot easier to learn . In a few days, we will update the single chip microcomputer of the electronic game MSP430.