Diff: grove_barometer.cpp

Revision:

0:3d05d80776f9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/grove_barometer.cpp	Tue Jun 09 10:17:13 2015 +0000
@@ -0,0 +1,176 @@
+
+
+#include "suli2.h"
+#include "grove_barometer.h"
+
+
+
+//local functions
+static char _read_char(I2C_T *i2c, unsigned char addr);
+static int _read_int(I2C_T *i2c, unsigned char addr);
+static unsigned short grove_barometer_readut(I2C_T *i2c);
+static unsigned long grove_barometer_readup(I2C_T *i2c);
+
+
+
+
+//local variables
+static unsigned char cmdbuf[2];
+static unsigned char databuf[2];
+static const unsigned char OSS = 0;
+static short ac1, ac2, ac3;
+static unsigned short ac4, ac5, ac6;
+static short b1, b2;
+static short mb, mc, md;
+static long PressureCompensate;
+static long _pressure;
+
+
+void grove_barometer_init(I2C_T *i2c, int pinsda, int pinscl)
+{
+    suli_i2c_init(i2c, pinsda, pinscl);
+}
+
+// Read 1 byte from the BMP085
+static char _read_char(I2C_T *i2c, unsigned char addr)
+{
+    suli_i2c_write(i2c, BMP085_ADDRESS, &addr, 1);
+    suli_i2c_read(i2c, BMP085_ADDRESS, databuf, 1);
+    return databuf[0];
+}
+
+// Read 2 bytes from the BMP085
+static int _read_int(I2C_T *i2c, unsigned char addr)
+{
+    suli_i2c_write(i2c, BMP085_ADDRESS, &addr, 1);
+    suli_i2c_read(i2c, BMP085_ADDRESS, databuf, 2);
+    return (databuf[0] << 8) + databuf[1];
+}
+
+bool grove_barometer_write_setup(I2C_T *i2c)
+{
+    ac1 = _read_int(i2c, 0xAA);
+    ac2 = _read_int(i2c, 0xAC);
+    ac3 = _read_int(i2c, 0xAE);
+    ac4 = _read_int(i2c, 0xB0);
+    ac5 = _read_int(i2c, 0xB2);
+    ac6 = _read_int(i2c, 0xB4);
+    b1 = _read_int(i2c, 0xB6);
+    b2 = _read_int(i2c, 0xB8);
+    mb = _read_int(i2c, 0xBA);
+    mc = _read_int(i2c, 0xBC);
+    md = _read_int(i2c, 0xBE);
+    
+    return true;
+}
+
+// Read the uncompensated temperature value
+static unsigned short grove_barometer_readut(I2C_T *i2c)
+{
+    unsigned short ut;
+    
+//    Wire.beginTransmission(BMP085_ADDRESS);
+//    Wire.write(0xF4);
+//    Wire.write(0x2E);
+//    Wire.endTransmission();
+    cmdbuf[0] = 0xF4;
+    cmdbuf[1] = 0x2E;
+    suli_i2c_write(i2c, BMP085_ADDRESS, cmdbuf, 2);  // POWER UP
+    
+    
+    suli_delay_ms(5);
+    //ut = bmp085ReadInt(0xF6);
+    ut = _read_int(i2c, 0xF6);
+    
+    return ut;
+}
+
+// Read the uncompensated pressure value
+static unsigned long grove_barometer_readup(I2C_T *i2c)
+{
+    unsigned char msb, lsb, xlsb;
+    unsigned long up = 0;
+    
+//    Wire.beginTransmission(BMP085_ADDRESS);
+//    Wire.write(0xF4);
+//    Wire.write(0x34 + (OSS<<6));
+//    Wire.endTransmission();
+    cmdbuf[0] = 0xF4;
+    cmdbuf[1] = 0x34 + (OSS<<6);
+    suli_i2c_write(i2c, BMP085_ADDRESS, cmdbuf, 2);  // POWER UP
+    
+    
+    suli_delay_ms(2 + (3<<OSS));
+
+    // Read register 0xF6 (MSB), 0xF7 (LSB), and 0xF8 (XLSB)
+//    msb = bmp085Read(0xF6);
+//    lsb = bmp085Read(0xF7);
+//    xlsb = bmp085Read(0xF8);
+     msb = _read_char(i2c, 0xF6);
+    lsb = _read_char(i2c, 0xF7);
+    xlsb = _read_char(i2c, 0xF8);
+    
+    up = (((unsigned long) msb << 16) | ((unsigned long) lsb << 8) | (unsigned long) xlsb) >> (8-OSS);
+    
+    return up;
+}
+
+bool grove_barometer_gettemperature(I2C_T *i2c, float *temperature)
+{
+    long x1, x2;
+    unsigned short ut = grove_barometer_readut(i2c);
+    
+    x1 = (((long)ut - (long)ac6)*(long)ac5) >> 15;
+    x2 = ((long)mc << 11)/(x1 + md);
+    PressureCompensate = x1 + x2;
+
+    float temp = ((PressureCompensate + 8)>>4);
+    *temperature = temp /10;
+    
+    return true;
+}
+
+bool grove_barometer_getpressure(I2C_T *i2c, long *pressure)
+{
+    long x1, x2, x3, b3, b6, p;
+    unsigned long b4, b7;
+    unsigned long up = grove_barometer_readup(i2c);
+    
+    b6 = PressureCompensate - 4000;
+    x1 = (b2 * (b6 * b6)>>12)>>11;
+    x2 = (ac2 * b6)>>11;
+    x3 = x1 + x2;
+    b3 = (((((long)ac1)*4 + x3)<<OSS) + 2)>>2;
+
+    // Calculate B4
+    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;
+    p += (x1 + x2 + 3791)>>4;
+
+    _pressure = p;
+    *pressure = _pressure;
+    return true;
+}
+
+bool grove_barometer_calcaltitude(I2C_T *i2c, float *altitude)
+{
+    float A = _pressure/101325;
+    float B = 1/5.25588;
+    float C = pow(A,B);
+    C = 1 - C;
+    C = C /0.0000225577;
+    *altitude = C;
+    return true;
+}