void temp_calibration(void)
{
uint8_t buf[2];
I2C_Read(Open_I2C,ADDR_24LC02,0xaa,buf, 2);
ac1 = buf[0] << 8 |buf[1];
I2C_Read(Open_I2C,ADDR_24LC02,0xac,buf, 2);
ac2 = buf[0] << 8 |buf[1];
I2C_Read(Open_I2C,ADDR_24LC02,0xae,buf, 2);
ac3 = buf[0] << 8 |buf[1];
I2C_Read(Open_I2C,ADDR_24LC02,0xb0,buf, 2);
ac4 = buf[0] << 8 |buf[1];
I2C_Read(Open_I2C,ADDR_24LC02,0xb2,buf, 2);
ac5 = buf[0] << 8 |buf[1];
I2C_Read(Open_I2C,ADDR_24LC02,0xb4,buf, 2);
ac6 = buf[0] << 8 |buf[1];
I2C_Read(Open_I2C,ADDR_24LC02,0xb6,buf, 2);
b1 = buf[0] << 8 |buf[1];
I2C_Read(Open_I2C,ADDR_24LC02,0xb8,buf, 2);
b2 = buf[0] << 8 |buf[1];
I2C_Read(Open_I2C,ADDR_24LC02,0xba,buf, 2);
mb = buf[0] << 8 |buf[1];
I2C_Read(Open_I2C,ADDR_24LC02,0xbc,buf, 2);
mc = buf[0] << 8 |buf[1];
I2C_Read(Open_I2C,ADDR_24LC02,0xbe,buf, 2);
md = buf[0] << 8 |buf[1];
printf("ac1=%d,ac2=%d,ac3=%d,ac4=%d,ac5=%d,ac6=%d,b1=%d,b2=%d,mb=%d,mc=%d,md=%d\r\n",ac1,ac2,ac3,ac4,ac5,ac6,b1,b2,mb,mc,md);
}
int main(void)
{
long x1,x2,x3,b3,b5,b6,b7,press_reg,pressure,temp_reg,temp;
unsigned long b4;
int ret,i;
uint8_t ReadBuffer[10];
//unsigned short ;
//unsigned int ;
char oss = 0; //这个值在读气压时可以置进寄存器
//GPIO_Configuration();
USART_Configuration();
I2C_Configuration();
printf("\r\n****************************************************************\r\n");
while (1)
{
printf("\r\n Read start \r\n");
temp_calibration();
//read uncompensated temperature
I2C_WriteOneByte(Open_I2C,ADDR_24LC02,0xf4,0x2e);
I2C_delay(200000);//delay 4.5ms
ret = I2C_Read(Open_I2C,ADDR_24LC02,0xf6,ReadBuffer,2);
temp_reg = ReadBuffer[0] << 8 | ReadBuffer[1];
printf("temp_reg %d \r\n",temp_reg);
//calculate true temperature
x1 = ((temp_reg - ac6) * ac5) >> 15;
x2 = (mc << 11) / (x1 + md);
b5 = x1 + x2;
temp = (b5 + 8) >> 4;
printf("x1:%d, x2:%d, b5:%d, temp(*0.1):%d \r\n",x1,x2,b5,temp);
//read uncompensated pressure
I2C_WriteOneByte(Open_I2C,ADDR_24LC02,0xf4,(0x3e + oss<<6));
I2C_delay(200000);//delay 4.5ms
ret = I2C_Read(Open_I2C,ADDR_24LC02,0xf6,ReadBuffer,3);
press_reg = ((ReadBuffer[0] << 16) | (ReadBuffer[1] << 8) | ReadBuffer[2]) >> (8 - oss);
printf("press_reg %d \r\n",press_reg);
//下面计算公式要注意括号的使用，模棱两可的都给它用上，一开始我觉得有些地方应该可以不用，计算出的气压结果却是错的，后来加上括号就对了
b6 = b5 - 4000;
printf("b6 %ld \r\n",b6);
x1 = (b2 * (b6 * b6 )>> 12) >> 11;
printf("x1 %ld \r\n",x1);
x2 = (ac2 * b6) >> 11;
printf("x2 %ld \r\n",x2);
x3 = x1 + x2;
printf("x3 %ld \r\n",x3);
b3 = ((((long)ac1 * 4 + x3) << oss) + 2) / 4;
printf("b3 %ld \r\n",b3);
x1 = (ac3 * b6) >> 13;
printf("x1 %ld \r\n",x1);
x2 = (b1 * (b6 * b6) >> 12) >> 16;
printf("x2 %ld \r\n",x2);
x3 = ((x1 + x2 )+ 2) >> 2;
printf("x3 %ld \r\n",x3);
b4 = (ac4 * (unsigned long)(x3 + 32768)) >> 15;
printf("b4 %ld \r\n",b4);
b7 = ((unsigned long)press_reg - b3) * (50000 >> oss);
printf("b7 %ld \r\n",b7);
if(b7 < 0x80000000)
{
pressure = (b7 * 2) / b4;
}
else
{
pressure = (b7 / b4) * 2;
}
printf("pressure %ld \r\n",pressure);
x1 = (pressure >> 8) * (pressure >> 8);
printf("x1 %ld \r\n",x1);
x1 = (x1 * 3038) >> 16;
printf("x1 %ld \r\n",x1);
x2 = (-7357 * pressure) >> 16;
printf("x2 %ld \r\n",x2);
pressure = pressure + ((x1 + x2 + 3791) >> 4);
printf("pressure %ld \r\n",pressure);
for(i=0; i<200*3; i++)
I2C_delay(200000);//delay 4.5ms
}
}
终端看到的打印：
Read start
ac1=8361,ac2=-816,ac3=-14464,ac4=33064,ac5=25477,ac6=25325,b1=5498,b2=38,mb=-32768,mc=-11075,md=2432
temp_reg 33455
x1:6321, x2:-2591, b5:3730, temp(*0.1):233
press_reg 33455
b6 -270
x1 0
x2 107
x3 107
b3 8388
x1 476
x2 1
x3 119
b4 33184
b7 1253350000
pressure 75539
x1 87025
x1 4034
x2 -8480
pressure 75498
温度233×0.1=23.3度
气压为75498Pa |
