Embedded Design and Development Project-LIS302DL Acceleration Sensor Program Design
LIS302DL is a three-axis ±2g/±8g intelligent digital output acceleration sensor that provides I2C and SPI interfaces . The expansion board uses the I2C interface and the device address is 0x38 .
1. Implemented functions
- ①pitch: The angle between the X axis and the horizontal plane, corresponding to the pitch angle of the human body forward and backward;
- ②roll: the angle between the Y axis and the horizontal plane, corresponding to the side slip angle of the human body from left to right;
- ③paw: The angle between the Z axis and the vertical direction, corresponding to the rotation angle of the human body around the Z axis;
- ④ Real-time printing of X, Y, Z real-time data of the three-axis acceleration sensor;
2. Realize the code according to the function
1. The main file main.c
#include"key.h"
#include"led.h"
#include"lcd.h"
#include "stdio.h"
#include "lis302.h"
unsigned char ucSec,ucSec1;
unsigned char pucBuf[1];
unsigned char pucStr[21];
unsigned long ulTick_ms;
void LIS_Proc(void);
int main(void)
{
SysTick_Config(72000); //定时1ms(HCLK = 72MHz)
KEY_Init();
LED_Init();
STM3210B_LCD_Init();
LCD_Clear(Blue);
LCD_SetBackColor(Blue);
LCD_SetTextColor(White);
i2c_init();
pucBuf[0] = 0x47;
i2c_write(pucBuf,0x20,1);
while(1)
{
LED_Disp(ucSec);
LIS_Proc();
}
}
void LIS_Proc(void)
{
if(ucSec != ucSec1)
{
ucSec1 = ucSec;
i2c_read(pucBuf,0x29,1);
sprintf((char*)pucStr," OutX:%02x",pucBuf[0]);
LCD_DisplayStringLine(Line4,pucStr);
i2c_read(pucBuf,0x2B,1);
sprintf((char*)pucStr," OutY:%02x",pucBuf[0]);
LCD_DisplayStringLine(Line5,pucStr);
i2c_read(pucBuf,0x2D,1);
sprintf((char*)pucStr," OutZ:%02x",pucBuf[0]);
LCD_DisplayStringLine(Line6,pucStr);
}
}
//SysTick 中断处理程序
void SysTick_Handler(void)
{
ulTick_ms++;
if(ulTick_ms % 1000 ==0)
ucSec++;
}
Main function analysis: ❤️ ❤️ ❤️
- Obtain the acceleration data of the X-axis through the X-axis output register 0x29 ;
- Obtain the acceleration data of the X-axis through the Y-axis output register 0x2B ;
- Obtain the acceleration data of the X-axis through the Z-axis output register 0x2D ;
2. The header file "lis302.h" of LIS302DL
#ifndef __LIS302_H__
#define __LIS302_H__
#include "stm32f10x.h"
void i2c_init(void);
void delay1(unsigned int n);
void I2CStart(void);
void I2CStop(void);
void I2CSendAck(void);
void I2CSendNotAck(void);
unsigned char I2CWaitAck(void);
void I2CSendByte(unsigned char cSendByte);
unsigned char I2CReceiveByte(void);
void i2c_write(unsigned char* pucBuf,unsigned char ucAddr,
unsigned char ucNum);
void i2c_read(unsigned char* pucBuf,unsigned char ucAddr,
unsigned char ucNum);
#endif
Brief analysis: ❤️ ❤️
- Except for the different header files, others are the same as the statement of the AT24C02 memory chip, please refer to: Embedded Design and Development Project - AT24C02 Memory Application Design ;
- Use the I2C protocol for communication, and can directly transplant the I2C driver;
3. The source file "lis302.c" of LIS302DL
#include "lis302.h"
/** I2C 总线接口 */
#define I2C_PORT GPIOA
#define SDA_Pin GPIO_Pin_5
#define SCL_Pin GPIO_Pin_4
#define FAILURE 0
#define SUCCESS 1
//配置SDA信号线为输入模式
void SDA_Input_Mode()
{
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = SDA_Pin;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPD;
GPIO_Init(I2C_PORT, &GPIO_InitStructure);
}
//配置SDA信号线为输出模式
void SDA_Output_Mode()
{
GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = SDA_Pin;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
GPIO_Init(I2C_PORT, &GPIO_InitStructure);
}
//
void SDA_Output( uint16_t val )
{
if ( val ) {
GPIO_SetBits(I2C_PORT,SDA_Pin);
} else {
GPIO_ResetBits(I2C_PORT,SDA_Pin);
}
}
//
void SCL_Output( uint16_t val )
{
if ( val ) {
GPIO_SetBits(I2C_PORT,SCL_Pin);
} else {
GPIO_ResetBits(I2C_PORT,SCL_Pin);
}
}
//
uint8_t SDA_Input()
{
return GPIO_ReadInputDataBit( I2C_PORT, SDA_Pin);
}
//延时程序
void delay1(unsigned int n)
{
unsigned int i;
for ( i=0;i<n;++i);
}
//I2C总线启动
void I2CStart(void)
{
SDA_Output(1);delay1(500);
SCL_Output(1);delay1(500);
SDA_Output(0);delay1(500);
SCL_Output(0);delay1(500);
}
//I2C总线停止
void I2CStop(void)
{
SCL_Output(0); delay1(500);
SDA_Output(0); delay1(500);
SCL_Output(1); delay1(500);
SDA_Output(1); delay1(500);
}
//等待应答
unsigned char I2CWaitAck(void)
{
unsigned short cErrTime = 5;
SDA_Input_Mode();
delay1(500);
SCL_Output(1);delay1(500);
while(SDA_Input())
{
cErrTime--;
delay1(500);
if (0 == cErrTime)
{
SDA_Output_Mode();
I2CStop();
return FAILURE;
}
}
//修改顺序
SCL_Output(0);delay1(500);
SDA_Output_Mode();
return SUCCESS;
}
//发送应答位
void I2CSendAck(void)
{
SDA_Output(0);delay1(500);
delay1(500);
SCL_Output(1); delay1(500);
SCL_Output(0); delay1(500);
}
//
void I2CSendNotAck(void)
{
SDA_Output(1);
delay1(500);
SCL_Output(1); delay1(500);
SCL_Output(0); delay1(500);
}
//通过I2C总线发送一个字节数据
void I2CSendByte(unsigned char cSendByte)
{
unsigned char i = 8;
while (i--)
{
SCL_Output(0);delay1(500);
SDA_Output(cSendByte & 0x80); delay1(500);
cSendByte += cSendByte; //左移一位
delay1(500);
SCL_Output(1);delay1(500);
}
SCL_Output(0);delay1(500);
}
//从I2C总线接收一个字节数据
unsigned char I2CReceiveByte(void)
{
unsigned char i = 8;
unsigned char cR_Byte = 0;
SDA_Input_Mode();
while (i--)
{
cR_Byte += cR_Byte; //左移一位
SCL_Output(0);delay1(500);
delay1(500);
SCL_Output(1);delay1(500);
cR_Byte |= SDA_Input();
}
SCL_Output(0);delay1(500);
SDA_Output_Mode();
return cR_Byte;
}
//I2C总线初始化
void i2c_init()
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);
GPIO_InitStructure.GPIO_Pin = SDA_Pin | SCL_Pin;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_2MHz;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP; // **
GPIO_Init(I2C_PORT, &GPIO_InitStructure);
}
//lis302dl加速度传感器 读
void i2c_read(unsigned char* pucBuf,unsigned char ucAddr,
unsigned char ucNum)
{
I2CStart();
I2CSendByte(0x38);
I2CWaitAck();
I2CSendByte(ucAddr);
I2CWaitAck();
I2CStart();
I2CSendByte(0x39);
I2CWaitAck();
while(ucNum--)
{
*pucBuf++ = I2CReceiveByte();
if(ucNum)
I2CSendAck();
else
I2CSendNotAck();
}
I2CStop();
}
//lis302dl加速度传感器 写
void i2c_write(unsigned char* pucBuf,unsigned char ucAddr,
unsigned char ucNum)
{
I2CStart();
I2CSendByte(0x38);
I2CWaitAck();
I2CSendByte(ucAddr);
I2CWaitAck();
while(ucNum--)
{
I2CSendByte(*pucBuf++);
I2CWaitAck();
}
I2CStop();
delay1(500);
}
Brief analysis: ❤️ ❤️
- Each I2C slave device has a unique device address, which can be directly modified to 0x38 , and others do not need to be modified;
- When reading the lis302 acceleration data through the i2c_read() function, first send 0x38 , select the sensor, then send the address of the register , and finally send the read command 0x39 to read the data;
- Write i2c_write(), send 0x38 and register address, you can write data, no need to write data for now;
3. Attention and learning points in the process of realizing functions
1. Precautions
- It is necessary to connect correctly and disconnect the pins that are not used to prevent conflicts ;
- When copying the IIC driver of AT24C02, it is necessary to modify the conditional compilation of the header file and modify the address of the current device ;
- Write 0x47 data to the 0x20 control register first , and set it to normal mode;
2. Knowledge points learned
- ① Obtain the required three-axis sensor data according to the address of the register;
- ② Deepen the understanding of the development and application of I2C in single-chip microcomputer;
- ③Learn to transplant the I2C driver to other chips or sensors, only need to modify the device address and header file ;
- ④ Realize the acquisition of real-time data of the X-axis, Y-axis, and Z-axis of the LIS302DL three-axis acceleration sensor;
❤️ ❤️ ❤️ ❤️ ❤️ ❤️