bmp280，请求大神指点

kbq1950361006 · 发表于 2018-1-23 09:15:42

调了能有一周了，bmp280，用iic通讯，一直调出数据不对，地址什么的都是按照说明来的，0xec，大神指点一下是不是还差哪里没有配置对，附上程序

#define BMP280_SlaveAddress 0xec    //定义器件在IIC总线中的从地址

#define OSS 0 // Oversampling Setting (note: code is not set up to use other OSS values)

unsigned short dig_T1;
short dig_T2;
short dig_T3;
unsigned short dig_P1;
short dig_P2;
short dig_P3;
short dig_P4;
short dig_P5;
short dig_P6;
short dig_P7;
short dig_P8;
short dig_P9;

void delay() //略微延时  6us约>4.7us
{
_nop_();
  _nop_();
_nop_();
_nop_();
      _nop_();
      _nop_();
}
void iic_start() //启动信号
{
  SDA=1;
  SCL=1;
  delay();
  SDA=0;
  delay();
  SCL=0;
}
void iic_stop()  //停止信号
{
SDA=0;
SCL=1;
delay();
SDA=1;
delay();
SCL=0;
}

void iic_ack() //应答信号
{
uchar i=0;
SCL=1;
delay();
while((SDA==1)&&(i<255))
i++;
SCL=0;
delay();
}

void iic_send_byte(uchar bat)  //发送数据
{
uchar i,temp;
temp=bat;
for(i=0;i<=7;i++)
{
   temp=temp<<1;
   SCL=0;
   SDA=CY;
   delay();
   SCL=1;
   delay();
}
SCL=0;
delay();
SDA=1;
delay();
}

unsigned char iic_rev()  //接受数据
{
  uchar temp,i;
  SCL=0;
  delay();
  SDA=1;
  for(i=0;i<=7;i++)
  {
SCL=1;
delay();
temp=(temp<<1)|SDA;
SCL=0;
delay();
  }
  delay();
  return temp;
}

uchar Single_Read(uchar ST_Address)
{
uchar REG_data;
//uchar bit;

iic_start(); //起始信号
iic_send_byte(BMP280_SlaveAddress);          //发送设备地址+写信号
iic_ack();
iic_send_byte(ST_Address);          //发送存储单元地址
iic_ack();
iic_start();                         //起始信号
iic_send_byte(BMP280_SlaveAddress+1);       //发送设备地址+读信号
iic_ack();
REG_data = iic_rev();
iic_ack(); //最后一个数据需要回NOACK
return REG_data;
}

void Single_Write(uchar SlaveAddress,uchar REG_Address,uchar REG_data)
{
iic_start();                      //起始信号
iic_send_byte(SlaveAddress); //发送设备地址+写信号
iic_ack();
iic_send_byte(REG_Address); //内部寄存器地址
iic_ack();
iic_send_byte(REG_data);    //内部寄存器数据
iic_ack();
iic_stop();                //发送停止信号
}

//*********************************************************
//读出BMP085内部数据,连续两个
//*********************************************************
short Multiple_read(uchar ST_Address)
{
uchar msb, lsb;
short _data;

lsb = Single_Read(ST_Address);
msb = Single_Read(ST_Address+1);

_data = msb << 8;
_data |= lsb;
//rt_kprintf("data is %x %x\n",msb,lsb);
return _data;
}
//*********************************************************
//读出BMP085内部数据,连续三个
//*********************************************************
long Multiple_three_read(uchar ST_Address)
{
uchar msb, lsb,xlsb;
long _data = 0;

msb = Single_Read(ST_Address);
lsb = Single_Read(ST_Address+1);
xlsb = Single_Read(ST_Address+2);

//rt_kprintf("data is %x %x %x\n",msb,lsb,xlsb);

_data = msb << 16;
_data |= lsb << 8;
_data |= xlsb;
_data = _data >> 4;
return _data;
}

//**************************************************************

//初始化BMP280，根据需要请参考pdf进行修改**************
void Init_BMP280(void)
{
unsigned short temp = 0;
unsigned char write_byte;

temp = Single_Read(0xd0);//

dig_T1 = Multiple_read(0x88);
dig_T2 = Multiple_read(0x8A);
dig_T3 = Multiple_read(0x8C);
dig_P1 = Multiple_read(0x8E);
dig_P2 = Multiple_read(0x90);
dig_P3 = Multiple_read(0x92);
dig_P4 = Multiple_read(0x94);
dig_P5 = Multiple_read(0x96);
dig_P6 = Multiple_read(0x98);
dig_P7 = Multiple_read(0x9A);
dig_P8 = Multiple_read(0x9C);
dig_P9 = Multiple_read(0x9E);

write_byte = 0x91;
Single_Write(BMP280_SlaveAddress,0xf4,write_byte);
write_byte = 0x00;//配置
Single_Write(BMP280_SlaveAddress,0xf5,write_byte);//5<<2
//rt_thread_delay(RT_TICK_PER_SECOND);
Delay_N1ms(200);
}
//***********************************************************************

long bmp280Convert(void)
{
long adc_T;
long adc_P;
long var1, var2,t_fine,T,p;

   //rt_kprintf("----------------------------\n");

//adc_T = Multiple_three_read(0xFA);
adc_T = Multiple_three_read(0xFA); // 读取温度
//adc_P = Multiple_three_read(0xF7);
adc_P = Multiple_three_read(0xF7); // 读取压强

if(adc_P == 0)
{
return 0;
}
//Temperature
var1 = (((double)adc_T)/16384.0-((double)dig_T1)/1024.0)*((double)dig_T2);
//rt_kprintf("var1 is %d\n",var1);
var2 = ((((double)adc_T)/131072.0-((double)dig_T1)/8192.0)*(((double)adc_T)/131072.0-((double)dig_T1)/8192.0))*((double)dig_T3);
//rt_kprintf("var2 is %d\n",var2);

t_fine = (uint32)(var1+var2);
//rt_kprintf("t_fine is %d\n",t_fine);

T = (var1+var2)/5120.0;
T = T;
//rt_kprintf("temperature is %d\n",T);

var1 = ((double)t_fine/2.0)-64000.0;
//rt_kprintf("var1 is %d\n",var1);

var2 = var1*var1*((double)dig_P6)/32768.0;
//rt_kprintf("var2 is %d\n",var2);

var2 = var2+var1*((double)dig_P5)*2.0;
//rt_kprintf("var2 is %d\n",var2);

var2 = (var2/4.0)+(((double)dig_P4)*65536.0);
//rt_kprintf("var2 is %d\n",var2);

var1 = (((double)dig_P3)*var1*var1/524288.0+((double)dig_P2)*var1)/524288.0;
//rt_kprintf("var1 is %d\n",var1);

var1 = (1.0+var1/32768.0)*((double)dig_P1);
//rt_kprintf("var1 is %d\n",var1);

p = 1048576.0-(double)adc_P;
//rt_kprintf("p is %d\n",p);

p = (p-(var2/4096.0))*6250.0/var1;
//rt_kprintf("p is %d\n",p);

var1 = ((double)dig_P9)*p*p/2147483648.0;
//rt_kprintf("var1 is %d\n",var1);

var2 = p*((double)dig_P8)/32768.0;
//rt_kprintf("var2 is %d\n",var2);

p = p+(var1+var2+((double)dig_P7))/16.0;

//rt_kprintf("pressure is %d\n",p);
return p;
}

int get_pressure(void)
{ int pressure = 0;
int i = 0;
   SDA=1;
SCL=1;
Delay_N1ms(200);                      //上电延时
Init_BMP280();             //初始化BMP085
while(i < 3)
{
pressure = bmp280Convert();
i++;
}

// printf("pressure is %d\n",pressure);
Single_Write(BMP280_SlaveAddress,0xf4,0x24);
return pressure;
}