stm32l476g-discovery ADC转换 USART
接着我的上一帖。我打算usart显示ADC转化后的数值 aResultDMA ，但是依旧有问题(显示0.000，如图所示)。求大神指导啊，V：chongzi15896main.c 文件内容：1.#include "stm32l476g_discovery.h"2.#include "stm32l476xx.h"3.#include "stm32l4xx_hal_conf.h"4.#include "adc.h"5.#include "SysClock.h"6.#include "LED.h"7.#include "UART.h"8.#include "main.h"9.#include "string.h"10. #include "stdio.h"11.12. char RxComByte = 0;13. uint8_t buffer;14. /* ADC handle declaration */15. ADC_HandleTypeDef AdcHandle;16.17. /* ADC channel configurationstructure declaration */18. ADC_ChannelConfTypeDef sConfig;19.20. /* Converted value declaration */21. uint32_t aResultDMA;22.23. int main(void){24.25. int a,n,i;26. float b;27. a=1100;28. 29.30. HAL_Init();31. System_Clock_Init();// SwitchSystem Clock = 80 MHz32. LED_Init();33. UART2_Init();34. ADCx_CLK_ENABLE();35. ADCx_CHANNEL_GPIO_CLK_ENABLE();36. DMAx_CHANNELx_CLK_ENABLE();37. ADCx_FORCE_RESET();38. ADCx_RELEASE_RESET();39.40. b=(float)aResultDMA*3300/4069;41. while (1){42. n= sprintf((char *)buffer, "a = %d\t", a);43. n+= sprintf((char *)buffer +n, "b = %f \r\n", b);44. USART_Write(USART2,buffer, n);45. a= a + 1;46. for (i = 0; i < 8000000; i++); // Delay47. Red_LED_On();48.49. }50. /* ### - 1 - Initialize ADCperipheral #################################### */51. AdcHandle.Instance = ADC1;52. if (HAL_ADC_DeInit(&AdcHandle) != HAL_OK)53. {54. /* ADC de-initialization Error */55. Red_LED_On();56. }57.58. AdcHandle.Init.ClockPrescaler =ADC_CLOCK_ASYNC_DIV1; /* Asynchronous clock mode, inputADC clock not divided */59. AdcHandle.Init.Resolution =ADC_RESOLUTION_12B; /* 12-bit resolution for converteddata */60. AdcHandle.Init.DataAlign = ADC_DATAALIGN_RIGHT; /* Right-alignment for converted data */61. AdcHandle.Init.ScanConvMode = DISABLE; /* Sequencer disabled (ADC conversion ononly 1 channel: channel set on rank 1) */62. AdcHandle.Init.EOCSelection =ADC_EOC_SINGLE_CONV; /* EOC flag picked-up to indicateconversion end */63. AdcHandle.Init.LowPowerAutoWait = DISABLE; /* Auto-delayed conversion feature disabled*/64. AdcHandle.Init.ContinuousConvMode = ENABLE; /* Continuous mode enabled(automatic conversion restart after each conversion) */65. AdcHandle.Init.NbrOfConversion = 1; /* Parameter discarded becausesequencer is disabled */66. AdcHandle.Init.DiscontinuousConvMode = DISABLE; /* Parameter discarded because sequencer isdisabled */67. AdcHandle.Init.NbrOfDiscConversion =1; /* Parameter discarded becausesequencer is disabled */68. AdcHandle.Init.ExternalTrigConv =ADC_SOFTWARE_START; /* Software start to trigthe 1st conversion manually, without external event */69. AdcHandle.Init.ExternalTrigConvEdge=ADC_EXTERNALTRIGCONVEDGE_NONE; /* Parameter discarded because software trigger chosen */70. AdcHandle.Init.DMAContinuousRequests = ENABLE; /* DMA circular mode selected */71. AdcHandle.Init.Overrun =ADC_OVR_DATA_OVERWRITTEN; /* DR register is overwritten withthe last conversion result in case of overrun */72. AdcHandle.Init.OversamplingMode = DISABLE; /* No oversampling */73.74. /* Initialize ADC peripheral according to the passedparameters */75. HAL_ADC_Init(&AdcHandle);76. if (HAL_ADC_Init(&AdcHandle) != HAL_OK)77. {78. Red_LED_On();79. }80.81.82. /* ### - 2 - Start calibration############################################ */83. HAL_ADCEx_Calibration_Start(&AdcHandle,ADC_SINGLE_ENDED);84. if (HAL_ADCEx_Calibration_Start(&AdcHandle, ADC_SINGLE_ENDED) !=HAL_OK)85. {86. Red_LED_On();87. }88.89. /* ### - 3 - Channel configuration######################################## */90. sConfig.Channel =ADCx_CHANNEL; /* Sampled channel number */91. sConfig.Rank = ADC_REGULAR_RANK_1; /* Rank of sampled channel numberADCx_CHANNEL */92. sConfig.SamplingTime = ADC_SAMPLETIME_6CYCLES_5; /* Sampling time (number of clock cycles unit) */93. sConfig.SingleDiff =ADC_SINGLE_ENDED; /* Single-ended input channel */94. sConfig.OffsetNumber = ADC_OFFSET_NONE; /* No offset subtraction */95. sConfig.Offset = 0; /* Parameter discarded becauseoffset correction is disabled */96. HAL_ADC_ConfigChannel(&AdcHandle,&sConfig);97. if (HAL_ADC_ConfigChannel(&AdcHandle, &sConfig) != HAL_OK)98. {99. Green_LED_Toggle();100. }101. 102. /* ### - 4 - Start conversion in DMA mode################################# */103. HAL_ADC_Start_DMA(&AdcHandle,&aResultDMA, 1);104. if (HAL_ADC_Start_DMA(&AdcHandle, &aResultDMA, 1) != HAL_OK)105. {106. Green_LED_Toggle();107. }108. 109. 110. }
adc.c文件内容：
1. #include "main.h"2. 3. /** @addtogroupSTM32L4xx_HAL_Examples4. * @{5. */6. 7. /** @defgroup ADC_DMA_Transfer8. * @{9. */10. 11./* Private typedef-----------------------------------------------------------*/12./* Private define------------------------------------------------------------*/13./* Private macro -------------------------------------------------------------*/14./* Private variables---------------------------------------------------------*/15./* Private function prototypes-----------------------------------------------*/16./* Private functions---------------------------------------------------------*/17. 18./** @defgroup HAL_MSP_Private_Functions19. * @{20. */21. 22./**23.* @briefADC MSP Init24.* @paramhadc : ADC handle25.* @retval None26.*/27.void HAL_ADC_MspInit(ADC_HandleTypeDef *hadc)28.{29. GPIO_InitTypeDef GPIO_InitStruct;30. staticDMA_HandleTypeDef DmaHandle;31. 32. /*##-1- Enable peripheralsand GPIO Clocks #################################*/33. /* ADC Periph clock enable*/34. ADCx_CLK_ENABLE();35. /* ADC Periph interface clockconfiguration */36. __HAL_RCC_ADC_CONFIG(RCC_ADCCLKSOURCE_SYSCLK);37. /* Enable DMA clock */38. DMAx_CHANNELx_CLK_ENABLE();39. 40. __HAL_RCC_GPIOA_CLK_ENABLE();41. 42. /*##- 2- Configureperipheral GPIO #########################################*/43. /* ADC Channel GPIO pinconfiguration */44. GPIO_InitStruct.Pin =ADCx_CHANNEL_PIN;45. GPIO_InitStruct.Mode =GPIO_MODE_ANALOG_ADC_CONTROL;46. GPIO_InitStruct.Pull =GPIO_NOPULL;47. HAL_GPIO_Init(ADCx_CHANNEL_GPIO_PORT,&GPIO_InitStruct);48. /*##- 3- Configure DMA#####################################################*/49. 50. /***********************Configure DMA parameters ***************************/51. DmaHandle.Instance = DMA1_Channel1;52. DmaHandle.Init.Request = DMA_REQUEST_0;53. DmaHandle.Init.Direction = DMA_PERIPH_TO_MEMORY;54. DmaHandle.Init.PeriphInc = DMA_PINC_DISABLE;55. DmaHandle.Init.MemInc = DMA_MINC_ENABLE;56. DmaHandle.Init.PeriphDataAlignment =DMA_PDATAALIGN_WORD;57. DmaHandle.Init.MemDataAlignment = DMA_MDATAALIGN_WORD;58. DmaHandle.Init.Mode = DMA_CIRCULAR;59. DmaHandle.Init.Priority = DMA_PRIORITY_MEDIUM;60. 61. /* Deinitialize& Initialize the DMA for new transfer */62. HAL_DMA_DeInit(&DmaHandle);63. HAL_DMA_Init(&DmaHandle);64. 65. /* Associate the DMA handle*/66. __HAL_LINKDMA(hadc,DMA_Handle, DmaHandle);67. 68. /* NVIC configuration forDMA Input data interrupt */69. HAL_NVIC_SetPriority(DMA1_Channel1_IRQn, 1,0);70. HAL_NVIC_EnableIRQ(DMA1_Channel1_IRQn);71.}72. 73./**74. * @brief ADC MSPDe-Initialization75. * This function frees the hardwareresources used in this example:76. * - Disable the Peripheral's clock77. * - Revert GPIO to their default state78. * @param hadc: ADC handlepointer79. * @retval None80. */81.void HAL_ADC_MspDeInit(ADC_HandleTypeDef *hadc)82.{83. 84. /*##-1- Reset peripherals##################################################*/85. ADCx_FORCE_RESET();86. ADCx_RELEASE_RESET();87. /* ADC Periph clock disable88. (automatically reset allADC's) */89. __HAL_RCC_ADC_CLK_DISABLE();90. 91. /*##-2- Disable peripheralsand GPIO Clocks ################################*/92. /* De-initialize the ADCChannel GPIO pin */93. HAL_GPIO_DeInit(ADCx_CHANNEL_GPIO_PORT,ADCx_CHANNEL_PIN);94.}95. 96. 97. 98./**99. * @briefInitializes the Global MSP.100. * @paramNone101. * @retval None102. */
这个b=(float)aResultDMA*3300/4069;
没有在while()循环里，ADC转换结果aResultDMA在循环里没有赋值给b变量。 本帖最后由 bbbone 于 2018-9-5 18:42 编辑
wenyangzeng 发表于 2018-9-5 17:52
这个b=(float)aResultDMA*3300/4069;
没有在while()循环里，ADC转换结果aResultDMA在循环里没有赋值给b变量 ...
怎么修改呢？我把 b=(float)aResultDMA*3300/4069; 放到while里，依然没起作用啊
老哥
问题 出在第四步，main文件的102行 。 我在第四部后面加一个Green_LED_On,这个灯是不亮的。之前部分都会亮。
/* ### - 4 - Start conversion in DMA mode ################################# */
HAL_ADC_Start_DMA(&AdcHandle, &aResultDMA, 1);
if (HAL_ADC_Start_DMA(&AdcHandle, &aResultDMA, 1) != HAL_OK)
{
Red_LED_On();
}
Green_LED_On(); bbbone 发表于 2018-9-5 18:38
怎么修改呢？我把 b=(float)aResultDMA*3300/4069; 放到while里，依然没起作用啊
老哥
...
楼主应该先确保读到ADC值，才能正确赋值给变量b。
ST官方代码应该多参考
wenyangzeng 发表于 2018-9-5 20:03
楼主应该先确保读到ADC值，才能正确赋值给变量b。
ST官方代码应该多参考
:)我也是从example上找的ADC，我感觉我跟例子里写的都一样。尴尬了 bbbone 发表于 2018-9-5 20:18
我也是从example上找的ADC，我感觉我跟例子里写的都一样。尴尬了
楼主可以直接运行ST演示代码，读取正确ADC值后再运行自己的代码试试。 你以为和例子一样，那么，你把例子来尝试看看，如果不行就简化代码再尝试
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