本帖最后由 jinglixixi 于 2020-8-23 08:48 编辑
BMP085是一款基于I2C接口的数字式传感器，主要用于测量气温、气压及海拔高度等，我们可以通过模拟I2C接口的方式来驱动该传感器，以进行测量。 整体构成
BMP085与MCU的连接关系如下： SDA --- PC12 SCL --- PC11
定义引脚输出高低电平的语句为： #define SCL_Set() HT_GPIOC->SRR = GPIO_PIN_11 #define SCL_Clr() HT_GPIOC->RR = GPIO_PIN_11
#define SDA_Set() HT_GPIOC->SRR = GPIO_PIN_12 #define SDA_Clr() HT_GPIOC->RR = GPIO_PIN_12
BMP085的初始化函数为： - void Init_BMP085()
- {
- ac1 = Multiple_read(0xAA);
- ac2 = Multiple_read(0xAC);
- ac3 = Multiple_read(0xAE);
- ac4 = Multiple_read(0xB0);
- ac5 = Multiple_read(0xB2);
- ac6 = Multiple_read(0xB4);
- b1 = Multiple_read(0xB6);
- b2 = Multiple_read(0xB8);
- mb = Multiple_read(0xBA);
- mc = Multiple_read(0xBC);
- md = Multiple_read(0xBE);
- }
读取气温与气压的函数为： - void bmp085Convert()
- {
- unsigned int ut;
- unsigned long up;
- long x1, x2, b5, b6, x3, b3, p;
- unsigned long b4, b7;
-
- ut = bmp085ReadTemp();
- up = bmp085ReadPressure();
- x1 = (((long)ut - (long)ac6)*(long)ac5) >> 15;
- x2 = ((long) mc << 11) / (x1 + md);
- b5 = x1 + x2;
- temperature = ((b5 + 8) >> 4);
- b6 = b5 - 4000;
- x1 = (b2 * (b6 * b6)>>12)>>11;
- x2 = (ac2 * b6)>>11;
- x3 = x1 + x2;
- b3 = (((((long)ac1)*4 + x3)<<OSS) + 2)>>2;
- x1 = (ac3 * b6)>>13;
- x2 = (b1 * ((b6 * b6)>>12))>>16;
- x3 = ((x1 + x2) + 2)>>2;
- b4 = (ac4 * (unsigned long)(x3 + 32768))>>15;
- b7 = ((unsigned long)(up - b3) * (50000>>OSS));
- if (b7 < 0x80000000)
- p = (b7<<1)/b4;
- else
- p = (b7/b4)<<1;
- x1 = (p>>8) * (p>>8);
- x1 = (x1 * 3038)>>16;
- x2 = (-7357 * p)>>16;
- pressure = p+((x1 + x2 + 3791)>>4);
- }
获取海拔高度的函数为： - long BMP085_Get_Altitude(long Pressure)
- {
- long altitude;
- altitude=44330.0*(1-pow((double)Pressure/101325,1/5.255));
- altitude*=100;
- return altitude;
- }
检测的主程序为： - int main(void)
- {
- SYSTICK_ClockSourceConfig(SYSTICK_SRC_STCLK);
- SYSTICK_SetReloadValue(SystemCoreClock / 8 / 1000);
- SYSTICK_IntConfig(ENABLE);
- UxART_Configuration();
- IIC_Init();
- Init_BMP085();
- while(1)
- {
- bmp085Convert();
- ConvTemperature();
- ConvPressure();
- ConvAltitude();
- Delayms(1000);
- }
- }
检测值输出显示
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