请教ADC旋转按钮中函数调用问题

只看该作者 · 2015-1-20 17:23

获得Volunme的值
Volume = Get_ADC_Knob();
函数定义如下：
uint32_t Get_ADC_Knob(void)
{
uint32_t ADC_Raw_Data;
/* Clear the A/D ADI NT0 interrupt flag */
EADC_CLR_INT_FLAG(EADC, 0x1);

//Trigger sample module 0 to start A/D conversion
EADC_START_CONV(EADC, 0x1);

/* Wait ADC interrupt (g_u32AdcIntFlag will be set at IRQ_Handler function) */
while(EADC_GET_INT_FLAG(EADC, 0x1) == 0);
ADC_Raw_Data = EADC_GET_CONV_DATA(EADC, 0);

return ADC_Raw_Data;
}

EADC_GET_CONV_DATA函数的定义如下：
/**
  * @brief Get the conversion data of the user-specified sample module.
  * @param[in] eadc Base address of EADC module.
  * @param[in] u32ModuleNum Decides the sample module number, valid value are from 0 to 18.
  * @return Return the conversion data of the user-specified sample module.
  * @details This macro is used to read RESULT bit (EADC_DATn[15:0], n=0~18) field to get conversion data.
  */
#define EADC_GET_CONV_DATA(eadc, u32ModuleNum) ((eadc)->DAT[(u32ModuleNum)] & EADC_DAT_RESULT_Msk)

我的问题是在函数Get_ADC_Knob()中EADC_GET_CONV_DATA(EADC, 0)，u32ModuleNum的值不是已经被设定为0了吗，那么它又是如何根据我旋转按钮而最终改变volume的值的？？
还是我的理解有错？volume的值究竟是如何根据我旋转MCU上的按钮而随之改变的？

只看该作者 · 2015-1-20 18:53

问题已解决
EADC位于APB总线，地址空间为：0X4000_3000-0X4004_3FFF，变化范围为0-4095。
(eadc)->DAT[(u32ModuleNum)]中DAT数组定义如下：
/**
   * DATn, n=0~18
   * ===================================================================================================
   * Offset: 0x00-0x48  A/D Data Register n for Sample Module n, n=0~18
   * ---------------------------------------------------------------------------------------------------
   * |Bits |Field    |Descriptions
   * | :----: | :----: | :---- |
   * |[15:0]  |RESULT |A/D Conversion Result
   * |       |       |This field contains 12 bits conversion result.
   * |       |       |When DMOF (EADC_CTL[9]) is set to 0, 12-bit ADC conversion result with unsigned format will be filled in RESULT[11:0] and zero will be filled in RESULT[15:12].
   * |       |       |When DMOF (EADC_CTL[9]) set to 1, 12-bit ADC conversion result with 2'complement format will be filled in RESULT[11:0] and signed bits to will be filled in RESULT[15:12].
   * |[16] |OV       |Overrun Flag
   * |       |       |If converted data in RESULT[11:0] has not been read before new conversion result is loaded to this register, OV is set to 1.
   * |       |       |0 = Data in RESULT[11:0] is recent conversion result.
   * |       |       |1 = Data in RESULT[11:0] is overwrite.
   * |       |       |Note: It is cleared by hardware after EADC_DAT register is read.
   * |[17] |VALID    |Valid Flag
   * |       |       |This bit is set to 1 when corresponding sample module channel analog input conversion is completed and cleared by hardware after EADC_DAT register is read.
   * |       |       |0 = Data in RESULT[11:0] bits is not valid.
   * |       |       |1 = Data in RESULT[11:0] bits is valid.
   */
它用于存储APB EADC_BA返回的值，并且存在其0-11位中

请教ADC旋转按钮中函数调用问题

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