A/D转换器的功用是将模仿输入信号采样得到能够供给计算机进行处理的数字信号。开发板的A/D输入模块电路图如下
typedef struct
{
__IO uint32_t CR; /*!< Offset: 0x000 A/D Control Register (R/W) */
__IO uint32_t GDR; /*!< Offset: 0x004 A/D Global Data Register (R/W) */
uint32_t RESERVED0;
__IO uint32_t INTEN; /*!< Offset: 0x00C A/D Interrupt Enable Register (R/W) */
__IO uint32_t DR[8]; /*!< Offset: 0x010-0x02C A/D Channel 0..7 Data Register (R/W) */
__I uint32_t STAT; /*!< Offset: 0x030 A/D Status Register (R/ ) */
__IO uint32_t ADTRM;
} LPC_ADC_TypeDef;
ADC的初始化代码，首要设置了时钟频率，满意ADC操作的需求
void ADC_Init(LPC_ADC_TypeDef *ADCx, uint32_t rate)
{
uint32_t temp, tmp;
// Turn on power and clock
CLKPWR_ConfigPPWR(CLKPWR_PCONP_PCADC, ENABLE); //敞开ADC功用
ADCx->CR = 0; //操控寄存器初始化
//Enable PDN bit
tmp = ADC_CR_PDN;
// Set clock frequency
temp = CLKPWR_GetCLK(CLKPWR_CLKTYPE_PER); //设置时钟频率
/* The APB clock (PCLK_ADC0) is divided by (CLKDIV+1) to produce the clock for
* A/D converter, which should be less than or equal to 12.4MHz.
* A fully conversion requires 31 of these clocks.
* ADC clock = PCLK_ADC0 / (CLKDIV + 1);
* ADC rate = ADC clock / 31;
*/
temp = (temp /(rate * 31)) – 1;
tmp |= ADC_CR_CLKDIV(temp);
ADCx->CR = tmp; //装备了时钟频率
}
中止装备
/*********************************************************************//**
* @brief ADC interrupt configuration
* @param[in] ADCx pointer to LPC_ADC_TypeDef, should be: LPC_ADC
* @param[in] IntType: type of interrupt, should be:
* – ADC_ADINTEN0: Interrupt channel 0
* – ADC_ADINTEN1: Interrupt channel 1
* …
* – ADC_ADINTEN7: Interrupt channel 7
* – ADC_ADGINTEN: Individual channel/global flag done generate an interrupt
* @param[in] NewState:
* – SET : enable ADC interrupt
* – RESET: disable ADC interrupt
* @return None
**********************************************************************/
void ADC_IntConfig (LPC_ADC_TypeDef *ADCx, ADC_TYPE_INT_OPT IntType, FunctionalState NewState)
{
ADCx->INTEN &= ~ADC_INTEN_CH(IntType);
if (NewState){
ADCx->INTEN |= ADC_INTEN_CH(IntType);
}
}
设置通道
void ADC_ChannelCmd (LPC_ADC_TypeDef *ADCx, uint8_t Channel, FunctionalState NewState)
{
if (NewState == ENABLE) {
ADCx->CR |= ADC_CR_CH_SEL(Channel);
} else {
ADCx->CR &= ~ADC_CR_CH_SEL(Channel);
}
}
中止处理
void ADC_IRQHandler(void)
{
adc_value = 0;
if (ADC_ChannelGetStatus(LPC_ADC, TENGHUA_ADC_PREPARED_CHANNEL, ADC_DATA_DONE))
{
adc_value = ADC_ChannelGetData(LPC_ADC, TENGHUA_ADC_PREPARED_CHANNEL);
NV%&&&&&%_DisableIRQ(ADC_IRQn);
}
}
其实ADC是很简单和根底的，首要仍是把握好寄存器的运用。
