高校信息化建设网站系统微信,外贸网站建设560元,怎么做漫画网站,域名解析大全STM32模拟SPI协议获取24位模数转换#xff08;24bit ADC#xff09;芯片AD7791电压采样数据
STM32大部分芯片只有12位的ADC采样性能#xff0c;如果要实现更高精度的模数转换如24位ADC采样#xff0c;则需要连接外部ADC实现。AD7791是亚德诺(ADI)半导体一款用于低功耗、24…STM32模拟SPI协议获取24位模数转换24bit ADC芯片AD7791电压采样数据
STM32大部分芯片只有12位的ADC采样性能如果要实现更高精度的模数转换如24位ADC采样则需要连接外部ADC实现。AD7791是亚德诺(ADI)半导体一款用于低功耗、24位Σ-Δ型模数转换器(ADC) ,适合低频测量应用提供50 Hz/60 Hz同步抑制。
这里介绍基于AD7791的24位ADC采样实现。
AD7791控制协议
AD7791的管脚如下所示 AD7791可以工作在2.5V~5.25V供电范围VDD而用于模数转换的参考电压可以通过引脚REFIN()和REFIN(–)单独设置从而可以针对特定电压范围更高精度的采样。如果REFIN() - REFIN(–) 1V 则对应24位采样分辨率率为1/(2^24)0.00000006V。当然要使得这个级别的电压分辨率有效对电路噪声的控制要求也很高。 AIN()和AIN(-)用于连接输入信号通过芯片内部寄存器配置有两种转换模式即AIN()相对AIN(-)是单边电压或双边电压。单边电压模式采样值0x000000对应AIN()-AIN(-)0采样值0xFFFFFF对应AIN()-AIN(-)REFIN() - REFIN(–) 。双边电压模式采样值0x000000对应AIN()-AIN(-)-(REFIN() - REFIN(–))采样值0x800000对应AIN()-AIN(-)0采样值0xFFFFFF对应AIN()-AIN(-)REFIN() - REFIN(–) 。 AD7791通过SPI总线进行访问控制其中数据输出管脚DOUT也是转换完成可读取指示信号/RDY, 访问协议操作主要逻辑如下
向通讯寄存器发送指令设置采样的通道和读操作模式单次或连续并且设置下一次访问是对哪个寄存器进行操作以及进行的是读还是写写模式寄存器设置采用单次转换还是连续转换模式单边还是双边转换模式以及是否buffered模式buffered模式对应信号接收管脚端接收阻抗高阻模式以及buffered模式是否在输入端引用100ns电流源;在配置模式寄存器后可以再向通讯寄存器发送指令指示后续读取数据寄存器然后按照24位格式读取采样到的ADC值;芯片支持对供电电压的采样识别原理为供电电压内部LDO降压到1.17V作为VDD采样电路的参考供电而VDD本身分压到1/5接到ADC采样端。所以供电电压识别为(VDD采样值/16777216)1.175 V.可配置滤波寄存器以控制采样转换输出频率影响到噪声抑制级别可以读取状态寄存器获得一些状态信息。
STM32工程配置
这里以STM32F103C6T6及STM32CUBEIDE开发工具为例介绍AD7791的24位ADC采样实现。
首先建立基本工程并配置时钟 配置一个串口如UART2作为通讯打印输出口 再选择4根管脚作为模拟协议用的GPIO, 这里用PA15作为CSPB3作为CLKPB4作为MISO PB5作为MOSI各管脚上外部电阻上拉到AD7791的供电电压STM32的管脚配置为Open-drain模式从而可以兼容不同供电电压的AD7791访问连接, 因此STM32的GPIO也都选择为具有FT(5V耐压)能力的管脚。 保存并生成基本工程代码
STM32工程代码
AD7791的ADC数据读取有5种模式
单次转换单次单读单次转换多次单读读到同样的数据连续转换单次单读连续转换多次单读连续抓换多次连读 其中单读和连续的区别是单读的每次读取前要发送一次写操作连续的所有读取前只发送一次写操作。这里的工程代码对5种模式都做了函数实现。
代码采用的微秒级延时函数实现参考 STM32 HAL us delay微秒延时的指令延时实现方式及优化 代码用到串口打印printf函数的重载及采用的浮点转换函数参考 STM32 UART串口printf函数应用及浮点打印代码空间节省 (HAL)
完整的main.c工程代码如下
/* USER CODE BEGIN Header */
/********************************************************************************* file : main.c* brief : Main program body******************************************************************************* attention** Copyright (c) 2022 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.********************************************************************************/
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include main.h/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include usart.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 firstms1;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(msNum0) HAL_Delay(msNum);delayReg 0;while(delayReg!usNum) delayReg;
}/*
*Convert float to string type
*Written by Pegasus Yu in 2022
*stra: string address as mychar from char mychar[];
*float: float input like 12.345
*flen: fraction length as 3 for 12.345
*/
#include stdio.h
#include string.h
#include stdlib.h
#include math.h
void py_f2s4printf(char * stra, float x, uint8_t flen)
{uint32_t base;int64_t dn;char mc[32];base pow(10,flen);dn x*base;sprintf(stra, %d., (int)(dn/base));dn abs(dn);if(dn%base0){for(uint8_t j1;jflen;j){stra strcat(stra, 0);}return;}else{if(flen1){sprintf(mc, %d, (int)(dn%base));stra strcat(stra, mc);return;}for(uint8_t j1;jflen;j){if((dn%base)pow(10,j)){for(uint8_t k1;k(flen-j);k){stra strcat(stra, 0);}sprintf(mc, %d, (int)(dn%base));stra strcat(stra, mc);return;}}sprintf(mc, %d, (int)(dn%base));stra strcat(stra, mc);return;}
}
/* USER CODE END PD *//* Private macro -------------------------------------------------------------*/
/* USER CODE BEGIN PM */
#define AD7791_CS_LOW HAL_GPIO_WritePin(GPIOA, GPIO_PIN_15, GPIO_PIN_RESET)
#define AD7791_CS_HIGH HAL_GPIO_WritePin(GPIOA, GPIO_PIN_15, GPIO_PIN_SET)
#define AD7791_CLK_LOW HAL_GPIO_WritePin(GPIOB, GPIO_PIN_3, GPIO_PIN_RESET)
#define AD7791_CLK_HIGH HAL_GPIO_WritePin(GPIOB, GPIO_PIN_3, GPIO_PIN_SET)
#define AD7791_DIN_LOW HAL_GPIO_WritePin(GPIOB, GPIO_PIN_5, GPIO_PIN_RESET)
#define AD7791_DIN_HIGH HAL_GPIO_WritePin(GPIOB, GPIO_PIN_5, GPIO_PIN_SET)
#define AD7791_DOUT_nRDY HAL_GPIO_ReadPin(GPIOB, GPIO_PIN_4)void AD7791_RST(void)
{
/** The serial interface can be reset by writing a series of 1s on the DIN input. If a Logic 1 is written to the AD7791 line for at least* 32 serial clock cycles, the serial interface is reset.** The DOUT/ RDY pin operates as a Data Ready signal also, the line going low when a new data-word is available in the output register.* It is reset high when a read operation from the data register is complete.* It also goes high prior to the updating of the data register to indicate when not to read from the device to ensure that a data read is* not attempted while the register is being updated.*/AD7791_CS_HIGH;AD7791_DIN_HIGH;AD7791_CLK_HIGH;AD7791_CS_LOW;PY_Delay_us_t(1);for(uint8_t i0;i32;i){AD7791_CLK_LOW;PY_Delay_us_t(1);AD7791_CLK_HIGH;PY_Delay_us_t(1);}AD7791_DIN_LOW;AD7791_CS_HIGH;
}/** write access to any of the other registers on the part begins with a write operation to the communications register followed by a* write to the selected register.* A read operation from any other register (except when continuous read mode is selected) starts* with a write to the communications register followed by a read operation from the selected register.*/void AD7791_WR_1BYTE(uint8_t cmd) //write 8-bit data
{for(uint8_t i0; i8; i){AD7791_CLK_LOW;if ((cmdi)0x80) AD7791_DIN_HIGH;else AD7791_DIN_LOW;PY_Delay_us_t(1);AD7791_CLK_HIGH;PY_Delay_us_t(1);}}uint32_t AD7791_RD_3BYTE(void) //read 24-bit data
{uint8_t rbit 0;uint32_t rdata 0;for(uint8_t i1; i24; i){PY_Delay_us_t(1);AD7791_CLK_LOW;PY_Delay_us_t(1);AD7791_CLK_HIGH;rbit AD7791_DOUT_nRDY;if (rbit ! 0) rdata | (((uint32_t)rbit)(24-i));}return rdata;
}void AD7791_POWER_DOWN(void)
{AD7791_CLK_HIGH;AD7791_CS_LOW;AD7791_WR_1BYTE(0x10);AD7791_WR_1BYTE(0xc4);AD7791_CS_HIGH;
}uint8_t AD7791_READ_STATUS_REG(void)
{uint8_t rbit 0;uint8_t rdata 0;AD7791_CLK_HIGH;AD7791_CS_LOW;AD7791_WR_1BYTE(0x08);AD7791_DIN_LOW;AD7791_CLK_HIGH;for(uint8_t i1; i8; i){PY_Delay_us_t(1);AD7791_CLK_LOW;PY_Delay_us_t(1);AD7791_CLK_HIGH;rbit AD7791_DOUT_nRDY;if (rbit ! 0) rdata | ((rbit)(8-i));}AD7791_CS_HIGH;return rdata;
}uint8_t AD7791_SET_FILTER_REG(uint8_t data)
{/** Due to chip fault, 0 or 1 written to lowest bit of filter register will become 1. So to write 0x04 will get back-read value 0x05.* So dont write filter register if you want to keep 0x04 in filter register which will be filled 0x04 when power up.*/uint8_t mode 0x04; //default: clock without division, 16.6Hz output rateuint8_t rbit 0;uint8_t rdata 0;AD7791_CLK_HIGH;AD7791_CS_LOW;AD7791_WR_1BYTE(0x20);mode data;AD7791_WR_1BYTE(mode);AD7791_CS_HIGH;AD7791_RST();PY_Delay_us_t(1);AD7791_CLK_HIGH;AD7791_CS_LOW;AD7791_WR_1BYTE(0x28);AD7791_DIN_LOW;AD7791_CLK_HIGH;for(uint8_t i1; i8; i){PY_Delay_us_t(1);AD7791_CLK_LOW;PY_Delay_us_t(1);AD7791_CLK_HIGH;rbit AD7791_DOUT_nRDY;if (rbit ! 0) rdata | ((rbit)(8-i));}AD7791_CS_HIGH;return rdata;}uint32_t AD7791_SAMPLE_VDD_SINGLE(void)
{
/*
* Along with converting external voltages, the analog input chan-nel can be used to monitor the voltage on the VDD pin.
* When the CH1 and CH0 bits in the communications register are set to 1,
* the voltage on the VDD pin is internally attenuated by 5 and the resultant voltage is applied to the Σ-Δ modulator using an internal 1.17 V reference for analog to digital conversion.
*/uint32_t vdd 0;AD7791_CLK_HIGH;AD7791_CS_LOW;AD7791_WR_1BYTE(0x17);AD7791_WR_1BYTE(0x06);while(AD7791_DOUT_nRDY) ;AD7791_WR_1BYTE(0x3f);vdd AD7791_RD_3BYTE();AD7791_CS_HIGH;AD7791_RST();return vdd;/** voltage (vdd/16777216)*1.17*5*/
}/* ** Mode1: single conversion mode single read mode : get one-time 24-bit data (write operation advanced before read operation)* Mode2: single conversion mode multi-time single read mode: get multi-time same 24-bit data (write operation advanced before every read operation)* Mode3: continuous conversion mode single read mode: get one-time 24-bit data (write operation advanced before read operation)* Mode4: continuous conversion mode multi-time single read mode: get multi-time individual 24-bit data (write operation advanced before every read operation)* Mode5: continuous conversion mode continuous read mode: get multi-time individual 24-bit data (only once write operation for all read operations)*/void AD7791_Mode1_RD(uint32_t *result)
{AD7791_CLK_HIGH;AD7791_CS_LOW;//AD7791_WR_1BYTE(0x12); //used for AIN(–) – AIN(–) test onlyAD7791_WR_1BYTE(0x10);AD7791_WR_1BYTE(0x86);//single conversion mode, no burn-out current, uni-polar and bufferedwhile(AD7791_DOUT_nRDY) ;AD7791_WR_1BYTE(0x38);//single read(*result) AD7791_RD_3BYTE();AD7791_CS_HIGH;AD7791_RST();
}void AD7791_Mode2_RD(uint32_t *result, uint32_t times)
{AD7791_CLK_HIGH;AD7791_CS_LOW;AD7791_WR_1BYTE(0x10);AD7791_WR_1BYTE(0x86);//single conversion mode, no burn-out current, uni-polar and bufferedwhile(AD7791_DOUT_nRDY) ;for(uint32_t i0; itimes; i){AD7791_WR_1BYTE(0x38);//single readresult[i] AD7791_RD_3BYTE();PY_Delay_us_t(1);}AD7791_CS_HIGH;AD7791_RST();
}void AD7791_Mode3_RD(uint32_t *result)
{AD7791_CLK_HIGH;AD7791_CS_LOW;AD7791_WR_1BYTE(0x10);AD7791_WR_1BYTE(0x06);//continuous conversion mode, no burn-out current, uni-polar and bufferedwhile(AD7791_DOUT_nRDY) ;AD7791_WR_1BYTE(0x38);//single read(*result) AD7791_RD_3BYTE();AD7791_CS_HIGH;AD7791_RST();
}void AD7791_Mode4_RD(uint32_t *result, uint32_t times)
{AD7791_CLK_HIGH;AD7791_CS_LOW;AD7791_WR_1BYTE(0x10);AD7791_WR_1BYTE(0x06);//continuous conversion mode, no burn-out current, uni-polar and bufferedfor(uint32_t i0; itimes; i){while(AD7791_DOUT_nRDY) ;AD7791_WR_1BYTE(0x38);//single readresult[i] AD7791_RD_3BYTE();PY_Delay_us_t(1);}AD7791_CS_HIGH;AD7791_RST();
}void AD7791_Mode5_RD(uint32_t *result, uint32_t times)
{AD7791_CLK_HIGH;AD7791_CS_LOW;AD7791_WR_1BYTE(0x10);AD7791_WR_1BYTE(0x06);//continuous conversion mode, no burn-out current, uni-polar and bufferedAD7791_WR_1BYTE(0x3c);//continuous readfor(uint32_t i0; itimes; i){while(AD7791_DOUT_nRDY) ;result[i] AD7791_RD_3BYTE();PY_Delay_us_t(1);}AD7791_CS_HIGH;AD7791_RST();
}
/* 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 *//* USER CODE END 0 *//*** brief The application entry point.* retval int*/
int main(void)
{/* USER CODE BEGIN 1 */uint32_t AData[128];float vdd;char mychar[100];/* 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();/* USER CODE END 2 *//* Infinite loop *//* USER CODE BEGIN WHILE */while (1){printf(Status Register Read Value0x%02x\r\n, AD7791_READ_STATUS_REG());printf(Filter Register Set Value0x%02x\r\n, AD7791_SET_FILTER_REG(0x05));vdd ((float)AD7791_SAMPLE_VDD_SINGLE())*1.17*5/16777216;py_f2s4printf(mychar, vdd, 6);printf(VDD Sampling Read Value%s V\r\n, mychar);AD7791_Mode1_RD(AData);printf(Mode 1 Signal Sampling Read Value%d\r\n, AData[0]);AD7791_Mode2_RD(AData, 4);printf(Mode 2 Signal Sampling Read Value:\r\n%d\r\n%d\r\n%d\r\n%d\r\n, AData[0], AData[1], AData[2], AData[3]);AD7791_Mode3_RD(AData);printf(Mode 3 Signal Sampling Read Value%d\r\n, AData[0]);AD7791_Mode4_RD(AData, 4);printf(Mode 4 Signal Sampling Read Value:\r\n%d\r\n%d\r\n%d\r\n%d\r\n, AData[0], AData[1], AData[2], AData[3]);AD7791_Mode5_RD(AData, 4);printf(Mode 5 Signal Sampling Read Value:\r\n%d\r\n%d\r\n%d\r\n%d\r\n, AData[0], AData[1], AData[2], AData[3]);PY_Delay_us_t(1000000);printf(\r\n);/* 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};/** Initializes the RCC Oscillators according to the specified parameters* in the RCC_OscInitTypeDef structure.*/RCC_OscInitStruct.OscillatorType RCC_OSCILLATORTYPE_HSE;RCC_OscInitStruct.HSEState RCC_HSE_ON;RCC_OscInitStruct.HSEPredivValue RCC_HSE_PREDIV_DIV1;RCC_OscInitStruct.HSIState RCC_HSI_ON;RCC_OscInitStruct.PLL.PLLState RCC_PLL_ON;RCC_OscInitStruct.PLL.PLLSource RCC_PLLSOURCE_HSE;RCC_OscInitStruct.PLL.PLLMUL RCC_PLL_MUL9;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_CLOCKTYPE_PCLK2;RCC_ClkInitStruct.SYSCLKSource RCC_SYSCLKSOURCE_PLLCLK;RCC_ClkInitStruct.AHBCLKDivider RCC_SYSCLK_DIV1;RCC_ClkInitStruct.APB1CLKDivider RCC_HCLK_DIV2;RCC_ClkInitStruct.APB2CLKDivider 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;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};/* GPIO Ports Clock Enable */__HAL_RCC_GPIOD_CLK_ENABLE();__HAL_RCC_GPIOA_CLK_ENABLE();__HAL_RCC_GPIOB_CLK_ENABLE();/*Configure GPIO pin Output Level */HAL_GPIO_WritePin(GPIOA, GPIO_PIN_15, GPIO_PIN_SET);/*Configure GPIO pin Output Level */HAL_GPIO_WritePin(GPIOB, GPIO_PIN_3|GPIO_PIN_4|GPIO_PIN_5, GPIO_PIN_SET);/*Configure GPIO pin : PA15 */GPIO_InitStruct.Pin GPIO_PIN_15;GPIO_InitStruct.Mode GPIO_MODE_OUTPUT_OD;GPIO_InitStruct.Pull GPIO_NOPULL;GPIO_InitStruct.Speed GPIO_SPEED_FREQ_HIGH;HAL_GPIO_Init(GPIOA, GPIO_InitStruct);/*Configure GPIO pins : PB3 PB4 PB5 */GPIO_InitStruct.Pin GPIO_PIN_3|GPIO_PIN_4|GPIO_PIN_5;GPIO_InitStruct.Mode GPIO_MODE_OUTPUT_OD;GPIO_InitStruct.Pull GPIO_NOPULL;GPIO_InitStruct.Speed GPIO_SPEED_FREQ_HIGH;HAL_GPIO_Init(GPIOB, GPIO_InitStruct);}/* USER CODE BEGIN 4 *//* 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 */
STM32测试输出
串口测试输出如下
例程下载
STM32F103C6T6模拟SPI协议读取24位模数转换24bit ADC芯片AD7791数据例程
–End–
