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#申请原创#
BMP085是一款数字式温度大气压传感器，其接口方式为I2C，在OLED屏的配合下就可实现对环境温度及大气压的检测与显示，其效果如下图所示。 检测与显示效果 在检测电路中，这2个外挂器件与开发板的连接关系为： BMP085： SCL ---PC4 SDA--- PC5 OLED： SCL---PC20 SDA---PC21
这2个外挂器件的驱动控制均采用GPIO口模拟I2C的方式，其中BMP085以模拟方式发送字节数据的函数为： - void BMP085_Send_Byte(char txd)
- {
- char t;
- OUTPUT_MODE_SET();
- SCL_Clr1();
- for(t=0;t<8;t++)
- {
- if((txd & 0x80)>>7)
- SDA_Set1();
- else
- SDA_Clr1();
- txd<<=1;
- delay_us(5);
- SCL_Set1();
- delay_us(5);
- SCL_Clr1();
- delay_us(5);
- }
- }
以模拟方式接受字节数据的函数为： - char BMP085_Read_Byte(unsigned char ack)
- {
- unsigned char i,receive=0;
- INPUT_MODE_SET();
- for(i=0;i<8;i++)
- {
- SCL_Clr1();
- delay_us(5);
- SCL_Set1();
- receive<<=1;
- if(SDA_IN()==1) receive++;
- delay_us(5);
- }
- if(!ack)
- BMP085_NAck();
- else
- BMP085_Ack();
- return receive;
- }
读取温度的函数为： - long bmp085ReadTemp(void)
- {
- BMP085_Start();
- BMP085_Send_Byte(BMP085_SlaveAddress);
- while(BMP085_Wait_Ack());
- BMP085_Send_Byte(0xF4);
- while(BMP085_Wait_Ack());
- BMP085_Send_Byte(0x2E);
- while(BMP085_Wait_Ack());
- BMP085_Stop();
- SYSTICK_DelayMs(10);
- return (long) Multiple_read(0xF6);
- }
读取大气压的函数为： - long bmp085ReadPressure(void)
- {
- pressure = 0;
- BMP085_Start();
- BMP085_Send_Byte(BMP085_SlaveAddress);
- while(BMP085_Wait_Ack()){}
- BMP085_Send_Byte(0xF4);
- while(BMP085_Wait_Ack()){}
- BMP085_Send_Byte(0x34);
- while(BMP085_Wait_Ack()){}
- BMP085_Stop();
- SYSTICK_DelayMs(10);
- pressure = Multiple_read(0xF6);
- pressure &= 0x0000FFFF;
- return pressure;
- }
实现图示效果的主程序为： - int main ( void )
- {
- SYS_Initialize ( NULL );
- SYSTICK_TimerStart();
- PORT_REGS->GROUP[2].PORT_DIRSET = 1<<18;
- PORT_REGS->GROUP[2].PORT_DIRSET = 1<<20;
- PORT_REGS->GROUP[2].PORT_DIRSET = 1<<21;
- PORT_REGS->GROUP[2].PORT_DIRSET = 1<<4;
- PORT_REGS->GROUP[2].PORT_DIRCLR = 1<<5;
- PORT_REGS->GROUP[2].PORT_PINCFG[5] = 0x0;
- OLED_Init();
- OLED_Clear();
- OLED_Clear();
- OLED_ShowString(0,0,"t= C",16);
- OLED_ShowString(0,2,"p= KPa",16);
- Init_BMP085();
- SYSTICK_DelayMs(1000);
- SYSTICK_DelayMs(100);
- while(1)
- {
- bmp085Convert();
- OLED_ShowNum(24,0,temperature1/10,3,16);
- OLED_ShowNum(24,2,pressure/100,5,16);
- SYSTICK_DelayMs(500);
- }
- }
ATSAMD51EVK开发板除了MCC不好用之外，用起来还是比较得心应手的！
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