/*----------------------------------------------------------------------------
本例子通過串口發送AD0的值，AD0連接一個NTC溫度電阻

 
用手觸摸NTC溫度電阻,輸出數字將變化
使用我提供的串口調試工具，選擇【串口超級終端】波特率設置115200
 *---------------------------------------------------------------------------*/

#include <stm32f10x_lib.h>                        // STM32F10x Library Definitions
#include <stdio.h>
#include "STM32_Init.h"                           // STM32 Initialization
#include "STM32_Reg.h"

/*----------------------------------------------------------------------------
  從串口發送一個字節數據
  Write character to Serial Port.
 *----------------------------------------------------------------------------*/
int SendChar (int ch)  {

  //等待發送結束
  while (!(USART1->SR & USART_FLAG_TXE));
  //將數據放入發送寄存器
  USART1->DR = (ch & 0x1FF);

  return (ch);
}

/*----------------------------------------------------------------------------
  從串口讀取一個字節數據，直到讀到數據才返回
  Read character to Serial Port.
 *----------------------------------------------------------------------------*/
int GetKey (void)  {

  //等待接收結束
  while (!(USART1->SR & USART_FLAG_RXNE));
  //從接受寄存器讀取數據并返回
  return ((int)(USART1->DR & 0x1FF));
}


unsigned short int  ADC_ConvertedValue;
/*------------------------------------------------------------------------------
  Initialises the Analog/Digital converter
  PA1 (ADC Channel-0) is used as analog input
  use DMA Channel1 for ADC1 (see DMA request mapping)
  使用PA0-ADC1.0
 *------------------------------------------------------------------------------*/
void adc_Init (void) {

  RCC->APB2ENR |= RCC_APB2ENR_IOPAEN;			  //使能GPIO時鐘
  //GPIO設置為模擬輸入
  GPIOA->CRL &= ~0x00000000;
  GPIOA->CRH &= ~0x00000000;
  
  // enable periperal clock for DMA
  //使能DMA時鐘
  RCC->AHBENR |= (1<<0);
  // set channel1 memory address   
  //設置DMA內存地址，ADC轉換結果直接放入該地址
  DMA1_Channel1->CMAR  = (u32)&ADC_ConvertedValue;
  // set channel0 peripheral address
  //設置通道1外設地址
  DMA1_Channel1->CPAR  = (u32)&(ADC1->DR);
  // transmit 1 word
  //DMA傳送1個字
  DMA1_Channel1->CNDTR = 1;
  // configure DMA channel
  DMA1_Channel1->CCR   = 0x00002520;
  // DMA Channel 1 enable	   //使能DMA通道
  DMA1_Channel1->CCR  |= (1 << 0);                

  // enable periperal clock for ADC1  
  //使能ADC時鐘
  RCC->APB2ENR |= (1<<9);
  // only one conversion   // 只有1個轉換通道
  ADC1->SQR1  = 0x00000000;
  // set sample time channel0 (55,5 cycles)// (3bit)
  //通道1采樣周期55.5個時鐘周期
  ADC1->SMPR2 = 0x00000028;
  // set channel1 as 1st conversion	// (5bit)
  //第1個轉換通道是1通道
  ADC1->SQR3  = 0x00000000;
  // use independant mode, SCAN mode
  //使用獨立模式，掃描模式
  ADC1->CR1   = 0x00000100;
  // use data align right,continuous conversion
  //使用數據右對齊，連續轉換
  ADC1->CR2   = 0x000E0103;
  // EXTSEL = SWSTART 
  // enable ADC, DMA mode, no external Trigger
  // start SW conversion
  //允許ADC，DMA模式，無需外接觸發器
  //開始轉換
  ADC1->CR2  |=  0x00500000;					  
}

//軟件延時，非精確延時
void Delay(unsigned long time)
{unsigned long i,j;
  
	for(j=0; j<time; j++)
	{
	   for(i=0;i<12000;i++);
	}
}
/*----------------------------------------------------------------------------
  MAIN function
 *----------------------------------------------------------------------------*/
int main (void)
{
int AD_value;
  
  // STM32 setup
  //STM32初始化
  stm32_Init ();
  //ADC初始化
  adc_Init();
  printf ("ADC Example\r\n\r\n");

  while (1) 
  {
	   //Delay(1000);
	   
	   //為了方便觀察軟件仿真好觀察采用下面的延時
	   Delay(50);
	   //因為使用DMA操作，所以每次ADC轉換結束，ADC的值都被保存到ADC_ConvertedValue里
	   AD_value  = ADC_ConvertedValue;
	   //這里可以通過串口看到ADC的值
	   printf("AD value = 0x%04X\r\n", AD_value);
  } // end while
} // end main