我使用 MCU STM32F4 从 MAX30100 获取 FIFO 数据来测量心率。在收到的信号中，我可以看到心跳，但在样本中也失败了，如下所示：
我没有过滤器工作，但是当我在 Arduino 板上这样做时，没有过滤器的信号是不同的。我是丢失样品还是正常现象？我做错了什么？
MAX30100 数据表：https ://img.filipeflop.com/files/download/Datasheet_MAX30100.pdf
按照我的代码：
/* Includes ------------------------------------------------------------------*/
#include "main.h"
#include "usb_device.h"
/* Private define ------------------------------------------------------------*/
// FIFO registers
#define MAX30100_FIFO_W_POINTER 0x02
#define MAX30100_OVF_COUNTER 0x03
#define MAX30100_FIFO_R_POINTER 0x04
#define MAX30100_FIFO_DATA_REG 0x05
// configuration registers
#define MAX30100_MODE_CONFIG 0x06
#define MAX30100_SPO2_CONFIG 0x07
#define MAX30100_LED_CONFIG 0x09
// PART ID registers
#define MAX30100_PART_ID 0xFF
// MAX30100 I2C addresses
#define MAX30100_WADDRESS 0xAE // 8bit address converted to 7bit + W
#define MAX30100_RADDRESS 0xAF // 8bit address converted to 7bit + R
/* Private variables ---------------------------------------------------------*/
I2C_HandleTypeDef hi2c3;
char buffer[30];
unsigned long ir_buff[16] = {0}, red_buff[16] = {0};
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void MX_GPIO_Init(void);
static void MX_I2C3_Init(void);
uint8_t CDC_Transmit_FS(char* Buf, uint16_t Len);
uint8_t MAX30100_getNumSamp(uint16_t* ir_buff, uint16_t* red_buff);
uint8_t MAX30100_getPartID(void);
void MAX30100_reset(void);
void MAX30100_wakeup(void);
void MAX30100_SetHR (void);
void MAX30100_InitFIFO (void);
void MAX30100_setLEDs(uint8_t ledCurrentRed, uint8_t ledCurrentIr);
void MAX30100_setSR(uint8_t sr);
void MAX30100_setPW (uint8_t pw);
uint8_t MAX30100_read (uint8_t device_register);
void MAX30100_write (uint8_t device_register, uint8_t reg_data);
int main(void)
{
uint8_t id;
uint8_t i;
uint8_t samples;
uint16_t ir_average = 0;
uint16_t red_average = 0;
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_I2C3_Init();
MX_USB_DEVICE_Init();
HAL_Delay(10);
MAX30100_reset();
id = MAX30100_getPartID();
if (id == 0x11) //OK
// Set LED current
MAX30100_setLEDs(0x07, 0xFF);
// Set sample rate
MAX30100_setSR(0x00);
// Set pulse width
MAX30100_setPW(0x3);
// Set heart rate mode
MAX30100_SetHR ();
// Set RD and WR pointers to 0x00
MAX30100_InitFIFO();
// Wake up
MAX30100_wakeup();
while (1)
{
// Gets the number of samples in the FIFO and reads then
samples = MAX30100_getNumSamp((uint16_t*)ir_buff, (uint16_t*)red_buff);
if (samples > 0 )
{
// we have data in FIFO
HAL_GPIO_WritePin(GPIOC,GPIO_PIN_14,1); //LED ON
ir_average = 0;
red_average = 0;
for (i = 0; i < samples; i++)
{
ir_average += (uint16_t)ir_buff[i];
red_average += (uint16_t)red_buff[i];
}
ir_average /= samples; // calculate the average value for this reading
red_average /= samples;
memset(buffer,0,sizeof(buffer));
sprintf(buffer, "HR: %d,", (uint16_t)ir_average);
CDC_Transmit_FS((char*)buffer, 20); //print the ir value to CDC
}
else
{
// There's no data in FIFO
HAL_GPIO_WritePin(GPIOC,GPIO_PIN_14,0); //LED OFF
HAL_Delay(1); // Wait for samples to be aquired
}
}
}
void SystemClock_Config(void)
{
RCC_OscInitTypeDef RCC_OscInitStruct = {0};
RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
__HAL_RCC_PWR_CLK_ENABLE();
__HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE2);
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();
}
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_DIV2;
RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)
{
Error_Handler();
}
}
static void MX_I2C3_Init(void)
{
hi2c3.Instance = I2C3;
hi2c3.Init.ClockSpeed = 400000;
hi2c3.Init.DutyCycle = I2C_DUTYCYCLE_2;
hi2c3.Init.OwnAddress1 = 0;
hi2c3.Init.AddressingMode = I2C_ADDRESSINGMODE_7BIT;
hi2c3.Init.DualAddressMode = I2C_DUALADDRESS_DISABLE;
hi2c3.Init.OwnAddress2 = 0;
hi2c3.Init.GeneralCallMode = I2C_GENERALCALL_DISABLE;
hi2c3.Init.NoStretchMode = I2C_NOSTRETCH_DISABLE;
if (HAL_I2C_Init(&hi2c3) != HAL_OK)
{
Error_Handler();
}
}
static void MX_GPIO_Init(void)
{
GPIO_InitTypeDef GPIO_InitStruct = {0};
/* GPIO Ports Clock Enable */
__HAL_RCC_GPIOC_CLK_ENABLE();
__HAL_RCC_GPIOH_CLK_ENABLE();
__HAL_RCC_GPIOA_CLK_ENABLE();
/*Configure GPIO pin Output Level */
HAL_GPIO_WritePin(GPIOC, GPIO_PIN_14|GPIO_PIN_15, GPIO_PIN_RESET);
/*Configure GPIO pins : PC14 PC15 */
GPIO_InitStruct.Pin = GPIO_PIN_14|GPIO_PIN_15;
GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
GPIO_InitStruct.Pull = GPIO_NOPULL;
GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);
}
// Reads from register 0xFF
// should return 0x11
uint8_t MAX30100_getPartID(void)
{
uint8_t reg;
reg = MAX30100_read (MAX30100_PART_ID);
return reg;
}
// Resets the MAX30100 IC
void MAX30100_reset(void)
{
uint8_t reg;
reg = MAX30100_read (MAX30100_MODE_CONFIG);
// RESET bit is B6
// 0x40 = 0100 0000
reg = (reg | 0x40); // Set reset bit to 1
MAX30100_write (MAX30100_MODE_CONFIG, reg);
}
// Wakes up the MAX30100
void MAX30100_wakeup(void)
{
uint8_t reg;
reg = MAX30100_read (MAX30100_MODE_CONFIG);
reg = reg & 0x7F; // Set SHDN bit to 0
MAX30100_write (MAX30100_MODE_CONFIG, reg);
}
// Sets Heart rate mode
// This means MODE{2:0} = 0b010 (or 0x02 in hexadecimal)
void MAX30100_SetHR (void)
{
uint8_t reg;
reg = MAX30100_read (MAX30100_MODE_CONFIG);
// RESET bit is B7
// First we clear bits 2:0
reg = reg & 0xF8;
// Then we set bits 2:0 to 0x02
reg = reg | 0x02;
MAX30100_write (MAX30100_MODE_CONFIG, reg);
}
// Initializes FIFO
// Sets RD and WR pointers to 0
// Clears OVF
void MAX30100_InitFIFO (void)
{
MAX30100_write (MAX30100_FIFO_W_POINTER, 0x00);
MAX30100_write (MAX30100_FIFO_R_POINTER, 0x00);
MAX30100_write (MAX30100_OVF_COUNTER, 0x00);
}
// Sets LED currents
void MAX30100_setLEDs(uint8_t ledCurrentRed, uint8_t ledCurrentIr)
{
uint8_t reg;
reg = ( ledCurrentRed << 4 ) | ledCurrentIr;
MAX30100_write (MAX30100_LED_CONFIG, reg);
}
// Sets sample rate
// sample rate is bits 4:2 of register MAX30100_SPO2_CONFIG
// bitmask is 0xE3
void MAX30100_setSR (uint8_t sr)
{
uint8_t reg;
reg = MAX30100_read (MAX30100_SPO2_CONFIG);
reg = reg & 0xE3;
reg = reg | (sr << 2);
MAX30100_write (MAX30100_SPO2_CONFIG, reg);
}
// Sets pulse width
// sample rate is bits 1:0 of register MAX30100_SPO2_CONFIG
void MAX30100_setPW (uint8_t pw)
{
uint8_t reg;
reg = MAX30100_read (MAX30100_SPO2_CONFIG);
reg = reg & 0xFC;
reg = reg | pw;
MAX30100_write (MAX30100_SPO2_CONFIG, reg);
}
// Gets number of samples in FIFO and read then
uint8_t MAX30100_getNumSamp(uint16_t* ir_buff, uint16_t* red_buff)
{
uint8_t wreg;
uint8_t rreg;
uint8_t sampleNum;
uint8_t samples[4];
wreg = MAX30100_read (MAX30100_FIFO_W_POINTER);
rreg = MAX30100_read (MAX30100_FIFO_R_POINTER);
sampleNum = (abs( 16 + wreg - rreg ) % 16);
if(sampleNum > 0)
{
//HAL_I2C_Mem_Read(&hi2c3,MAX30100_RADDRESS,MAX30100_FIFO_DATA_REG,4,(uint8_t*)samples,1,1000);
HAL_I2C_Mem_Read(&hi2c3,MAX30100_RADDRESS,MAX30100_FIFO_DATA_REG,1,&samples[0],1,250);
HAL_I2C_Mem_Read(&hi2c3,MAX30100_RADDRESS,MAX30100_FIFO_DATA_REG,1,&samples[1],1,250);
HAL_I2C_Mem_Read(&hi2c3,MAX30100_RADDRESS,MAX30100_FIFO_DATA_REG,1,&samples[2],1,250);
HAL_I2C_Mem_Read(&hi2c3,MAX30100_RADDRESS,MAX30100_FIFO_DATA_REG,1,&samples[3],1,250);
*(ir_buff) = (uint16_t)samples[1];
*(ir_buff++) |= (uint16_t)samples[0] << 8;
*(red_buff) = (uint16_t)samples[3];
*(red_buff++) |= (uint16_t) samples[2] << 8;
//HAL_Delay(7); // just test
}
return sampleNum;
}
// My I2C read and write functions
uint8_t MAX30100_read (uint8_t device_register )
{
uint8_t read_data;
HAL_I2C_Mem_Read(&hi2c3,MAX30100_RADDRESS,device_register,I2C_MEMADD_SIZE_8BIT,&read_data,1,250);
return read_data;
}
void MAX30100_write (uint8_t device_register, uint8_t reg_data)
{
HAL_I2C_Mem_Write(&hi2c3,MAX30100_WADDRESS,device_register,I2C_MEMADD_SIZE_8BIT,®_data,1,250);
}