STM32讀取24位模數(shù)轉(zhuǎn)換(24bit ADC)芯片ADS1231數(shù)據(jù)
ADS1231是一款TI公司出品的24位ADC芯片,常用于與稱重傳感器配合實(shí)現(xiàn)體重計(jì)的應(yīng)用。這里介紹STM32讀取ADS1231的電路和代碼實(shí)現(xiàn)。ADS1231的特點(diǎn)為通過硬件管腳可控制兩種采樣速率(10SPS和80SPS),及可以控制芯片上下電以實(shí)現(xiàn)低功耗過程控制。
ADS1231的內(nèi)部原理如下圖所示(固定128倍輸入信號放大增益):
STM32電路連接
ADS1231與STM32的連接關(guān)系設(shè)計(jì)如下圖所示:
ADS1231的采樣模擬接口可以工作在和數(shù)字接口不同的電壓,如模擬供電 AVDD采用 5V,數(shù)字供電采用3.3V,從而與STM32的接口直接連接即可。
ADS1231測試電路
ADS1231典型的應(yīng)用連接到惠斯通電橋,接收差分電壓,由于內(nèi)部已固定為128倍信號放大,所以對于5V供電(AVDD),最大檢測差分電壓范圍為±20mV。需要注意輸入差分信號有共模電壓范圍要求:
簡單測試可以采用如下方式:
當(dāng)可調(diào)電阻器為10歐姆時(shí),IN+和IN-差分電壓為(5/(4700+4700+10))*10 = 5.31mV。而IN-端電壓為2.49734V,IN+端電壓為2.50265V,共模和差模電壓都在手冊電氣范圍內(nèi),可以微調(diào)可調(diào)電位器的阻值,調(diào)整輸出差模電壓。
ADS1231訪問協(xié)議
ADS1231可以通過硬件管腳SPEED控制采樣速率, 及通過/PWRDONW管腳控制芯片上下電:
讀取數(shù)據(jù)的時(shí)序則為:
- 檢測nRDY管腳(也是Dout管腳)狀態(tài),如為低電平則可以讀取數(shù)據(jù),如為高電平則不能讀取數(shù)據(jù) ;
- 當(dāng)數(shù)據(jù)可讀取時(shí), 發(fā)送24個(gè)時(shí)鐘,并在每個(gè)時(shí)鐘的下降沿獲得采樣數(shù)據(jù)的24位中的各個(gè)位,高位優(yōu)先接收到
- 24個(gè)時(shí)鐘之后,多發(fā)一個(gè)時(shí)鐘,使得nRDY管腳回到輸出高電平狀態(tài),在下一次數(shù)據(jù)可讀取時(shí),ADS1231會(huì)將信號拉低
STM32工程配置
這里采用STM32G031F8P6和STM32CUBEIDE開發(fā)環(huán)境,實(shí)現(xiàn)ADS1231的ADC數(shù)據(jù)讀取。
首先配置基本工程和時(shí)鐘系統(tǒng):
配置UART2作為通訊口。
配置與ADS1231連接的4個(gè)管腳:
保存并生成初始工程代碼:
STM32工程代碼
代碼主要實(shí)現(xiàn)微秒級的時(shí)序控制,采用的微秒延時(shí)函數(shù)參考: STM32 HAL us delay(微秒延時(shí))的指令延時(shí)實(shí)現(xiàn)方式及優(yōu)化
測試邏輯采用以下方式:
- 串口收到0x01命令,進(jìn)行10Hz輸出測試
- 串口收到0x02命令,進(jìn)行80Hz輸出測試
main.c文件完整代碼如下:
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
* @attention
*
* Copyright (c) 2023 STMicroelectronics.
* All rights reserved.
*
* This software is licensed under terms that can be found in the LICENSE file
* in the root directory of this software component.
* If no LICENSE file comes with this software, it is provided AS-IS.
*
******************************************************************************
*/
//Written by Pegasus Yu in 2023
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "string.h"
/* USER CODE END Includes */
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
/* USER CODE END PTD */
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
__IO float usDelayBase;
void PY_usDelayTest(void)
{
__IO uint32_t firstms, secondms;
__IO uint32_t counter = 0;
firstms = HAL_GetTick()+1;
secondms = firstms+1;
while(uwTick!=firstms) ;
while(uwTick!=secondms) counter++;
usDelayBase = ((float)counter)/1000;
}
void PY_Delay_us_t(uint32_t Delay)
{
__IO uint32_t delayReg;
__IO uint32_t usNum = (uint32_t)(Delay*usDelayBase);
delayReg = 0;
while(delayReg!=usNum) delayReg++;
}
void PY_usDelayOptimize(void)
{
__IO uint32_t firstms, secondms;
__IO float coe = 1.0;
firstms = HAL_GetTick();
PY_Delay_us_t(1000000) ;
secondms = HAL_GetTick();
coe = ((float)1000)/(secondms-firstms);
usDelayBase = coe*usDelayBase;
}
void PY_Delay_us(uint32_t Delay)
{
__IO uint32_t delayReg;
__IO uint32_t msNum = Delay/1000;
__IO uint32_t usNum = (uint32_t)((Delay%1000)*usDelayBase);
if(msNum>0) HAL_Delay(msNum);
delayReg = 0;
while(delayReg!=usNum) delayReg++;
}
/* USER CODE END PD */
/* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
#define ads1231_rdy (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_7)==0)?1:0
#define ads1231_clk_h HAL_GPIO_WritePin(GPIOA, GPIO_PIN_6, GPIO_PIN_SET)
#define ads1231_clk_l HAL_GPIO_WritePin(GPIOA, GPIO_PIN_6, GPIO_PIN_RESET)
#define ads1231_dout HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_7)
/* USER CODE END PM */
/* Private variables ---------------------------------------------------------*/
UART_HandleTypeDef huart2;
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_USART2_UART_Init(void);
/* USER CODE BEGIN PFP */
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
uint8_t cmd=0;
uint32_t ads1231_data;
uint32_t counter=0;
/* USER CODE END 0 */
/**
* @brief The application entry point.
* @retval int
*/
int main(void)
{
/* USER CODE BEGIN 1 */
/* USER CODE END 1 */
/* MCU Configuration--------------------------------------------------------*/
/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();
/* USER CODE BEGIN Init */
/* USER CODE END Init */
/* Configure the system clock */
SystemClock_Config();
/* USER CODE BEGIN SysInit */
/* USER CODE END SysInit */
/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_USART2_UART_Init();
/* USER CODE BEGIN 2 */
PY_usDelayTest();
PY_usDelayOptimize();
//hardware reset of ADS1231
HAL_GPIO_WritePin(ADS1231_nPDWN_GPIO_Port, ADS1231_nPDWN_Pin, GPIO_PIN_RESET);
PY_Delay_us_t(1000000);
HAL_GPIO_WritePin(ADS1231_nPDWN_GPIO_Port, ADS1231_nPDWN_Pin, GPIO_PIN_SET);
__HAL_UART_CLEAR_FLAG(&huart2, UART_FLAG_RXNE);
HAL_UART_Receive_IT(&huart2, (uint8_t *)&cmd, 1);
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
if(cmd==0x01) //10SPS
{
HAL_GPIO_WritePin(ADS1231_SPEED_GPIO_Port, ADS1231_SPEED_Pin, GPIO_PIN_RESET);
while(ads1231_rdy) PY_Delay_us_t(1);
while(!ads1231_rdy) PY_Delay_us_t(1);
ads1231_data = 0;
PY_Delay_us_t(1);
for(uint8_t i=1;i<=24;i++)
{
ads1231_clk_h;
PY_Delay_us_t(1);
ads1231_clk_l;
ads1231_data |= (ads1231_dout<<(24-i));
PY_Delay_us_t(1);
}
ads1231_clk_h;
PY_Delay_us_t(1);
ads1231_clk_l;
PY_Delay_us_t(1);
HAL_UART_Transmit(&huart2, &ads1231_data, 3, 2700);
counter++;
if(counter%10==0) PY_Delay_us_t(1000000);
}
if(cmd==0x02) //80SPS
{
HAL_GPIO_WritePin(ADS1231_SPEED_GPIO_Port, ADS1231_SPEED_Pin, GPIO_PIN_SET);
while(ads1231_rdy) PY_Delay_us_t(1);
while(!ads1231_rdy) PY_Delay_us_t(1);
ads1231_data = 0;
PY_Delay_us_t(1);
for(uint8_t i=1;i<=24;i++)
{
ads1231_clk_h;
PY_Delay_us_t(1);
ads1231_clk_l;
ads1231_data |= (ads1231_dout<<(24-i));
PY_Delay_us_t(1);
}
ads1231_clk_h;
PY_Delay_us_t(1);
ads1231_clk_l;
PY_Delay_us_t(1);
HAL_UART_Transmit(&huart2, &ads1231_data, 3, 2700);
counter++;
if(counter%80==0) PY_Delay_us_t(1000000);
}
/* USER CODE END WHILE */
/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}
/**
* @brief System Clock Configuration
* @retval None
*/
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
/** Configure the main internal regulator output voltage
*/
HAL_PWREx_ControlVoltageScaling(PWR_REGULATOR_VOLTAGE_SCALE1);
/** Initializes the RCC Oscillators according to the specified parameters
* in the RCC_OscInitTypeDef structure.
*/
RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSI;
RCC_OscInitStruct.HSIState = RCC_HSI_ON;
RCC_OscInitStruct.HSIDiv = RCC_HSI_DIV1;
RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSI;
RCC_OscInitStruct.PLL.PLLM = RCC_PLLM_DIV1;
RCC_OscInitStruct.PLL.PLLN = 8;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
RCC_OscInitStruct.PLL.PLLQ = RCC_PLLQ_DIV2;
RCC_OscInitStruct.PLL.PLLR = RCC_PLLR_DIV2;
if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
{
Error_Handler();
}
/** Initializes the CPU, AHB and APB buses clocks
*/
RCC_ClkInitStruct.ClockType = RCC_CLOCKTYPE_HCLK|RCC_CLOCKTYPE_SYSCLK
|RCC_CLOCKTYPE_PCLK1;
RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_2) != HAL_OK)
{
Error_Handler();
}
}
/**
* @brief USART2 Initialization Function
* @param None
* @retval None
*/
static void MX_USART2_UART_Init(void)
{
/* USER CODE BEGIN USART2_Init 0 */
/* USER CODE END USART2_Init 0 */
/* USER CODE BEGIN USART2_Init 1 */
/* USER CODE END USART2_Init 1 */
huart2.Instance = USART2;
huart2.Init.BaudRate = 115200;
huart2.Init.WordLength = UART_WORDLENGTH_8B;
huart2.Init.StopBits = UART_STOPBITS_1;
huart2.Init.Parity = UART_PARITY_NONE;
huart2.Init.Mode = UART_MODE_TX_RX;
huart2.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart2.Init.OverSampling = UART_OVERSAMPLING_16;
huart2.Init.OneBitSampling = UART_ONE_BIT_SAMPLE_DISABLE;
huart2.Init.ClockPrescaler = UART_PRESCALER_DIV1;
huart2.AdvancedInit.AdvFeatureInit = UART_ADVFEATURE_NO_INIT;
if (HAL_UART_Init(&huart2) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN USART2_Init 2 */
/* USER CODE END USART2_Init 2 */
}
/**
* @brief GPIO Initialization Function
* @param None
* @retval None
*/
static void MX_GPIO_Init(void)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
/* USER CODE BEGIN MX_GPIO_Init_1 */
/* USER CODE END MX_GPIO_Init_1 */
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOA_CLK_ENABLE();
/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(GPIOA, ADS1231_SPEED_Pin|ADS1231_SCK_Pin, GPIO_PIN_RESET);
/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(ADS1231_nPDWN_GPIO_Port, ADS1231_nPDWN_Pin, GPIO_PIN_SET);
/*Configure GPIO pins : ADS1231_SPEED_Pin ADS1231_nPDWN_Pin */
GPIO_InitStruct.Pin = ADS1231_SPEED_Pin|ADS1231_nPDWN_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
/*Configure GPIO pin : ADS1231_SCK_Pin */
GPIO_InitStruct.Pin = ADS1231_SCK_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
HAL_GPIO_Init(ADS1231_SCK_GPIO_Port, &GPIO_InitStruct);
/*Configure GPIO pin : ADS1231_nDRDY_DOUT_Pin */
GPIO_InitStruct.Pin = ADS1231_nDRDY_DOUT_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
GPIO_InitStruct.Pull = GPIO_PULLUP;
HAL_GPIO_Init(ADS1231_nDRDY_DOUT_GPIO_Port, &GPIO_InitStruct);
/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}
/* USER CODE BEGIN 4 */
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *UartHandle)
{
HAL_UART_Receive_IT(&huart2, (uint8_t *)&cmd, 1);
}
/* USER CODE END 4 */
/**
* @brief This function is executed in case of error occurrence.
* @retval None
*/
void Error_Handler(void)
{
/* USER CODE BEGIN Error_Handler_Debug */
/* User can add his own implementation to report the HAL error return state */
__disable_irq();
while (1)
{
}
/* USER CODE END Error_Handler_Debug */
}
#ifdef USE_FULL_ASSERT
/**
* @brief Reports the name of the source file and the source line number
* where the assert_param error has occurred.
* @param file: pointer to the source file name
* @param line: assert_param error line source number
* @retval None
*/
void assert_failed(uint8_t *file, uint32_t line)
{
/* USER CODE BEGIN 6 */
/* User can add his own implementation to report the file name and line number,
ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
/* USER CODE END 6 */
}
#endif /* USE_FULL_ASSERT */
代碼實(shí)現(xiàn)十六進(jìn)制數(shù)據(jù)輸出,如果要切換為串口printf打印輸出,可以參考:
STM32 UART串口printf函數(shù)應(yīng)用及浮點(diǎn)打印代碼空間節(jié)省 (HAL)
輸出的24位數(shù)據(jù)為補(bǔ)碼格式,進(jìn)行絕對值提取時(shí)按照如下規(guī)則:
測試效果
串口命令0x01輸出(間隔1秒輸出10個(gè)采樣值):
串口命令0x02輸出(間隔1秒輸出80個(gè)采樣值):
例程下載
STM32G031F8P6-ADS1231例程文章來源:http://www.zghlxwxcb.cn/news/detail-700942.html
–End–文章來源地址http://www.zghlxwxcb.cn/news/detail-700942.html
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