- #include "mbed.h"
- Serial pc(PA_9, PA_10);//定義串口
- I2C i2c(PB_7, PB_6);//定義i2c通信
- unsigned short int dig_P1, dig_T1;//定義引腳,變量
- short int dig_P2, dig_P3, dig_P4, dig_P5, dig_P6, dig_P7, dig_P8, dig_P9, dig_T2, dig_T3;
- double wendu, qiya, t_fine;//溫度,氣壓,補償
- const int addw = 0xEC;//寫入地址 Pin6:SDO(傳感器地址控制位,接GND的時候I2C中器件地址為0xEC,接高電平為0xEc+1
- const int addr = 0xED;//讀取地址
- //測量控制寄存器(ctrl_meas)(0xF4):
- //Bit7~Bit5:osrs_t[2:0] 控制溫度采樣模式,主要是采樣數據的位數(位數越大,精度越高),具體配置如下(本次三位都配置為1,最大采樣位數20Bit):
- //Bit4~Bit2:osrs_p[2:0] 控制大氣壓強采樣模式,主要是采樣數據的位數(位數越大,精度越高),具體配置如下(本次三位都配置為1,最大采樣位數20Bit):
- //Bit1~Bit0:mode[1:0] 傳感器工作模式控制,00為Sleep Mode,01/10為Forced Mode,11為 Normal Mode(本次配置為11)。
- //配置寄存器(config)(0xF5):
- //Bit7~Bit5:t_sb[2:0] 設置Normal Mode下的轉換間隔時間,具體配置如下(本次配置為000,0.5ms轉換一次)
- //Bit4~Bit2:filter[2:0] 設置傳感器接收外界信號時的,前端濾波電路的濾波系數的,可以有效減少外界環境的干擾: 本次000,不使用
- //Bit0:spi3w_en 與SPI模式有關,本次沒用到,沒設置。
- //身份編號寄存器(id)(0xD0):
- //寄存器內固定值為0x58,讀取0xD0數據的時候,傳感器返回0x58,代表身份辨認完畢。
- //復位寄存器(reset)(0xE0):
- //寫入0xB6時,所有寄存器(除身份編號寄存器)數據全部清零。
- /*
- 函數功能:讀取制定地址的數據
- 參數:寄存器地址
- 返回值:讀出的數據
- */
- uint8_t i2cread(char shuju)
- {
- char cmd[2];
- cmd[0] = shuju;
- i2c.write(addw, cmd, 1);
- i2c.read(addr, cmd, 1);
- return cmd[0];
- }
- /*
- 函數功能:計算溫度
- 參數:無
- 返回值:溫度
- */
- float bmp280_wendu()
- {
- long adc_P;
- uint32_t var1, var2;
- float T, p;
- var1 = (((double)wendu) / 16384.0 - ((double)dig_T1) / 1024.0) * ((double)dig_T2);
- var2 = ((((double)wendu) / 131072.0 - ((double)dig_T1) / 8192.0) * (((double)wendu) / 131072.0 - ((double)dig_T1) / 8192.0)) * ((double)dig_T2);
- t_fine = (uint32_t)(var1 + var2);
- T = (var1 + var2) / 5120.0;
- //bmp280自帶的補償算法
- return T;
- }
- /*
- 函數功能:計算氣壓
- 參數:無
- 返回值:無
- */
- float bmp280_qiya()
- {
- uint32_t var1, var2;
- float T, p;
- var1 = ((double)t_fine / 2.0) - 64000.0;
- var2 = var1 * var1 * ((double)dig_P6) / 32768.0;
- var2 = var2 + var1 * ((double)dig_P5) * 2.0;
- var2 = (var2 / 4.0) + (((double)dig_P4) * 65536.0);
- var1 = (((double)dig_P3) * var1 * var1 / 524288.0 + ((double)dig_P2) * var1) / 524288.0;
- var1 = (1.0 + var1 / 32768.0) * ((double)dig_P1);
- p = 1048576.0 - (double)qiya;
- p = (p - (var2 / 4096.0)) * 6250.0 / var1;
- var1 = ((double)dig_P9) * p * p / 2147483648.0;
- var2 = p * ((double)dig_P8) / 32768.0;
- p = p + (var1 + var2 + ((double)dig_P7)) / 16.0;
- return p;//bmp280自帶補償算法
- }
- /*
- 函數功能:讀取溫度,氣壓數據,存入定義的變量中
- 參數:無
- 返回值:無
- */
- void bmp280_shujucaiji(void)
- {
- uint8_t lsb, msb, xlsb;
- msb = i2cread(0xfa);//高8位
- lsb = i2cread(0xfb);//低8位
- xlsb = i2cread(0xfc);
- wendu = (msb << 12) | (lsb << 4) | (xlsb >> 4);//高位放最左邊,低位中間,xlsb后四位不要,注意datesheet中給的低位高位地址,是反的
- msb = i2cread(0xf7);
- lsb = i2cread(0xf8);
- xlsb = i2cread(0xf9);
- qiya = (msb << 12) | (lsb << 4) | (xlsb >> 4);
- }
- /*
- 函數功能:讀取實時補償
- 參數:無
- 返回值:無
- */
- void bmp280_buchang(void)
- {
- uint8_t lsb, msb;
- lsb = i2cread(0x88);
- msb = i2cread(0x89);
- dig_T1 = (msb << 8) | lsb;
- lsb = i2cread(0x8A);
- msb = i2cread(0x8B);
- dig_T2 = (msb << 8) | lsb;
- lsb = i2cread(0x8c);
- msb = i2cread(0x8d);
- dig_T3 = (msb << 8) | lsb;
- lsb = i2cread(0x8e);
- msb = i2cread(0x8f);
- dig_P1 = msb << 8 | lsb;
- lsb = i2cread(0x90);
- msb = i2cread(0x91);
- dig_P2 = msb << 8 | lsb;
- lsb = i2cread(0x92);
- msb = i2cread(0x93);
- dig_P3 = msb << 8 | lsb;
- lsb = i2cread(0x94);
- msb = i2cread(0x95);
- dig_P4 = msb << 8 | lsb;
- lsb = i2cread(0x96);
- msb = i2cread(0x97);
- dig_P5 = msb << 8 | lsb;
- lsb = i2cread(0x98);
- msb = i2cread(0x99);
- dig_P6 = msb << 8 | lsb;
- lsb = i2cread(0x9a);
- msb = i2cread(0x9b);
- dig_P7 = msb << 8 | lsb;
- lsb = i2cread(0x9c);
- msb = i2cread(0x9d);
- dig_P8 = msb << 8 | lsb;
- lsb = i2cread(0x9e);
- msb = i2cread(0x9f);
- dig_P9 = msb << 8 | lsb;
- }
- /*
- 函數功能:配置bmp280寄存器參數
- 參數:無
- 返回值:無
- */
- void bmp280_init(void)
- {
- char cmd[2], str[2];
- cmd[0] = 0xf4;
- cmd[1] = 0xff;
- str[0] = 0xf5;
- str[1] = 0x00;
- i2c.write(addw, cmd, 2);
- i2c.write(addw, str, 2);
- }
- int main()
- {
- bmp280_init();
- pc.baud(9600);//波特率配置
- wait(1);
- pc.printf("%d\n", i2cread(0xD0));
- while (1)
- {
- bmp280_buchang();
- bmp280_shujucaiji();
- pc.printf("%.6f\n", bmp280_wendu());
- pc.printf("%.6f\n", bmp280_qiya());
- wait(1);
- }
- }
復制代碼 |