STM32 SPI 访问配置霍尔磁编码器KTH7823
KTH7823是一款国产16 位高精度低延时霍尔磁编码器/角度传感器，电机运转时，可以通过编码器获取角度和位置以及计算出转速等信息。KTH7823芯片适应在轴和离轴监测方式。
如果采用多对级磁铁，则可以提高输出分辨率的稳定性。
这里介绍采用TM32CUBEIDE开发环境，及STM32F401RCT6访问配置KTH7823的过程。电路连接如图所示：
STM32硬件接口配置
首先进行STM32CUBEIDE的工程配置，建立新的工程并配置时钟和接口：
48MHz时钟是配置给USB VCOM所用，先要进行USB VCOM配置：
USB VCOM的配置使用也可以参考《STM32 USB VCOM和HID的区别，配置及Echo功能实现（HAL）》
配置SPI2作为通讯端口：
保存并生成基本工程代码：
KTH7823 SPI访问寄存器
KTH7823 SPI访问协议
KTH7823 角度计算
STM32访问功能规划
本例程将实现如下功能：
- 通过USB VCOM可以发送十六进制单字节命令到STM32
- 发送0x01和1个字节地址，通过SPI读取KTH7823地址对应的寄存器数据
- 发送0x02，1个字节地址，1个字节数据，通过SPI配置KTH7823特定地址的特定数据
- 发送0x03，通过SPI读取KTH7823角度数据
- 发送0x04, 通过SPI读取KTH7823角度数据并转换为角度
- 发送0x05, 通过SPI发送寄存器锁定命令，在KTH7823关电重启前不能再写操作寄存器
STM32工程代码
首先设置USB VCOM接收串口指令：
c
static int8_t CDC_Receive_FS(uint8_t* Buf, uint32_t *Len)
{
/* USER CODE BEGIN 6 */
extern uint8_t ucmd[8];
memcpy(ucmd, Buf, *Len);
USBD_CDC_SetRxBuffer(&hUsbDeviceFS, &Buf[0]);
USBD_CDC_ReceivePacket(&hUsbDeviceFS);
return (USBD_OK);
/* USER CODE END 6 */
}在main.c文件里实现全部的控制逻辑：
c
/* USER CODE BEGIN Header */
/**
******************************************************************************
* @file : main.c
* @brief : Main program body
******************************************************************************
* @attention
*
* Copyright (c) 2026 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.
*
******************************************************************************
*/
//For i2c access
//Pin "mode" = high
//Pin "SSI CS = high
/* USER CODE END Header */
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "usb_device.h"
/* Private includes ----------------------------------------------------------*/
/* USER CODE BEGIN Includes */
#include "string.h"
/* USER CODE END Includes */
/* Private typedef -----------------------------------------------------------*/
/* USER CODE BEGIN PTD */
__IO float semiusDelayBase = 0;
void PY_semiusDelayTest(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++;
semiusDelayBase = ((float)counter)/2000;
}
void PY_Delay_semius_t(uint32_t Delay)
{
__IO uint32_t delayReg;
__IO uint32_t semiusNum = (uint32_t)(Delay*semiusDelayBase);
delayReg = 0;
while(delayReg!=semiusNum) delayReg++;
}
void PY_semiusDelayOptimize(void)
{
__IO uint32_t firstms, secondms;
__IO float coe = 1.0;
firstms = HAL_GetTick();
PY_Delay_semius_t(2000000) ;
secondms = HAL_GetTick();
coe = ((float)1000)/(secondms-firstms);
semiusDelayBase = coe*semiusDelayBase;
}
void PY_Delay_semius(uint32_t Delay)
{
__IO uint32_t delayReg;
uint32_t msNum = Delay/2000;
uint32_t semiusNum = (uint32_t)((Delay%2000)*semiusDelayBase);
if(msNum>0) HAL_Delay(msNum);
delayReg = 0;
while(delayReg!=semiusNum) delayReg++;
}
void PY_Delay_us_t(uint32_t Delay)
{
PY_Delay_semius_t(Delay*2);
}
void PY_Delay_ms_t(uint32_t Delay)
{
PY_Delay_us_t(Delay*1000);
}
/* USER CODE END PTD */
/* Private define ------------------------------------------------------------*/
/* USER CODE BEGIN PD */
/*
*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%base==0)
{
for(uint8_t j=1;j<=flen;j++)
{
stra = strcat(stra, "0");
}
return;
}
else
{
if(flen==1){
sprintf(mc, "%d", (int)(dn%base));
stra = strcat(stra, mc);
return;
}
for(uint8_t j=1;j<flen;j++)
{
if((dn%base)<pow(10,j))
{
for(uint8_t k=1;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 */
uint8_t CDC_Transmit_FS(uint8_t* Buf, uint16_t Len);
/* USER CODE END PM */
/* Private variables ---------------------------------------------------------*/
SPI_HandleTypeDef hspi2;
/* USER CODE BEGIN PV */
/* USER CODE END PV */
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_SPI2_Init(void);
/* USER CODE BEGIN PFP */
#define SPI2_CS_L HAL_GPIO_WritePin(GPIOB, SPI2_CS_Pin, GPIO_PIN_RESET)
#define SPI2_CS_H HAL_GPIO_WritePin(GPIOB, SPI2_CS_Pin, GPIO_PIN_SET)
uint8_t SPI2_DATA[2];
uint8_t KTH7823_READ_REG(uint8_t addr)
{
uint16_t td = (0x01<<14) | ((addr&0x3F)<<8) | 0x0000;
uint16_t rd;
SPI2_CS_L;
HAL_SPI_TransmitReceive(&hspi2, &td, &rd, 1, 2700);
SPI2_CS_H;
PY_Delay_us_t(1);
SPI2_CS_L;
HAL_SPI_TransmitReceive(&hspi2, &td, &rd, 1, 2700);
SPI2_CS_H;
return (uint8_t)(rd>>8);
}
uint8_t KTH7823_WRITE_REG(uint8_t addr, uint8_t data)
{
uint16_t td = (0x02<<14) | ((addr&0x3F)<<8) | data;
uint16_t rd;
SPI2_CS_L;
HAL_SPI_TransmitReceive(&hspi2, &td, &rd, 1, 2700);
SPI2_CS_H;
PY_Delay_us_t(200000); //At least 20ms delay
td = 0x0000;
rd = 0;
SPI2_CS_L;
HAL_SPI_TransmitReceive(&hspi2, &td, &rd, 1, 2700);
SPI2_CS_H;
return (uint8_t)(rd>>8);
}
uint16_t KTH7823_READ_ANGLE(void)
{
uint16_t td = 0x0000;
uint16_t rd;
SPI2_CS_L;
HAL_SPI_TransmitReceive(&hspi2, &td, &rd, 1, 2700);
SPI2_CS_H;
PY_Delay_us_t(1);
SPI2_CS_L;
HAL_SPI_TransmitReceive(&hspi2, &td, &rd, 1, 2700);
SPI2_CS_H;
return rd;
}
void KTH7823_MODE_LOCK(void)
{
uint16_t td = 0xE802;
uint16_t rd;
SPI2_CS_L;
HAL_SPI_TransmitReceive(&hspi2, &td, &rd, 1, 2700);
SPI2_CS_H;
}
/* USER CODE END PFP */
/* Private user code ---------------------------------------------------------*/
/* USER CODE BEGIN 0 */
uint8_t ucmd[8];
char mychar[50];
char str0[80];
char * str1;
/* 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_USB_DEVICE_Init();
MX_SPI2_Init();
/* USER CODE BEGIN 2 */
PY_semiusDelayTest();
PY_semiusDelayOptimize();
/* USER CODE END 2 */
/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
if(ucmd[0] == 0x01)
{
ucmd[0] = 0;
uint8_t rst = KTH7823_READ_REG(ucmd[1]);
CDC_Transmit_FS((uint8_t *)(&rst), 1);
}
else if(ucmd[0] == 0x02)
{
ucmd[0] = 0;
uint8_t rst = KTH7823_WRITE_REG(ucmd[1], ucmd[2]);
if(rst==ucmd[2]) CDC_Transmit_FS((uint8_t *)"\r\nOK\r\n", strlen("\r\nOK\r\n"));
else CDC_Transmit_FS((uint8_t *)"\r\nFailure\r\n", strlen("\r\nFailure\r\n"));
}
else if(ucmd[0] == 0x03)
{
ucmd[0] = 0;
KTH7823_READ_ANGLE();
PY_Delay_us_t(1);
uint16_t rst = KTH7823_READ_ANGLE();
CDC_Transmit_FS((uint8_t *)(&rst), 2);
}
else if(ucmd[0] == 0x04)
{
ucmd[0] = 0;
KTH7823_READ_ANGLE();
PY_Delay_us_t(1);
uint16_t rst = KTH7823_READ_ANGLE();
float spi_angle_f = ((float)rst/65536)*360.0;
py_f2s4printf(mychar, spi_angle_f, 2);
sprintf(str0, "\r\nCurrent Degree = %s °\r\n", mychar);
CDC_Transmit_FS((uint8_t *)str0, strlen(str0));
}
else if(ucmd[0] == 0x05)
{
ucmd[0] = 0;
KTH7823_MODE_LOCK();
CDC_Transmit_FS((uint8_t *)"\r\nOK\r\n", strlen("\r\nOK\r\n"));
}
else PY_Delay_us_t(10);
/* 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_RCC_PWR_CLK_ENABLE();
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);
/** 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.PLL.PLLState = RCC_PLL_ON;
RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
RCC_OscInitStruct.PLL.PLLM = 25;
RCC_OscInitStruct.PLL.PLLN = 336;
RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV4;
RCC_OscInitStruct.PLL.PLLQ = 7;
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 SPI2 Initialization Function
* @param None
* @retval None
*/
static void MX_SPI2_Init(void)
{
/* USER CODE BEGIN SPI2_Init 0 */
/* USER CODE END SPI2_Init 0 */
/* USER CODE BEGIN SPI2_Init 1 */
/* USER CODE END SPI2_Init 1 */
/* SPI2 parameter configuration*/
hspi2.Instance = SPI2;
hspi2.Init.Mode = SPI_MODE_MASTER;
hspi2.Init.Direction = SPI_DIRECTION_2LINES;
hspi2.Init.DataSize = SPI_DATASIZE_16BIT;
hspi2.Init.CLKPolarity = SPI_POLARITY_HIGH;
hspi2.Init.CLKPhase = SPI_PHASE_2EDGE;
hspi2.Init.NSS = SPI_NSS_SOFT;
hspi2.Init.BaudRatePrescaler = SPI_BAUDRATEPRESCALER_32;
hspi2.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi2.Init.TIMode = SPI_TIMODE_DISABLE;
hspi2.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi2.Init.CRCPolynomial = 10;
if (HAL_SPI_Init(&hspi2) != HAL_OK)
{
Error_Handler();
}
/* USER CODE BEGIN SPI2_Init 2 */
/* USER CODE END SPI2_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_GPIOH_CLK_ENABLE();
__HAL_RCC_GPIOB_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(SPI2_CS_GPIO_Port, SPI2_CS_Pin, GPIO_PIN_SET);
/*Configure GPIO pin : SPI2_CS_Pin */
GPIO_InitStruct.Pin = SPI2_CS_Pin;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_VERY_HIGH;
HAL_GPIO_Init(SPI2_CS_GPIO_Port, &GPIO_InitStruct);
/* USER CODE BEGIN MX_GPIO_Init_2 */
/* USER CODE END MX_GPIO_Init_2 */
}
/* 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 */其中，USB VCOM打印输出的浮点转字符串函数参考：《STM32 UART串口printf函数应用及浮点打印代码空间节省 (HAL)》
STM32工程代码测试
通过串口工具连接并进行测试：
按照约90度转动电机轴
