/
bmp180.go
161 lines (133 loc) · 3.01 KB
/
bmp180.go
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//Texas Instruments INA219 high side current sensor
package bmp180
import (
"fmt"
"github.com/NeuralSpaz/i2c"
)
const (
BMP180_ADDRESS = 0x77
BMP180_CALREG_AC1 = 0xAA
BMP180_CALREG_AC2 = 0xAC
BMP180_CALREG_AC3 = 0xAE
BMP180_CALREG_AC4 = 0xB0
BMP180_CALREG_AC5 = 0xB2
BMP180_CALREG_AC6 = 0xB4
BMP180_CALREG_B1 = 0xB6
BMP180_CALREG_B2 = 0xB8
BMP180_CALREG_MB = 0xBA
BMP180_CALREG_MC = 0xBC
BMP180_CALREG_MD = 0xBE
BMP180_CONTROL = 0xF4
BMP180_TEMP = 0xF6
BMP180_PRESSURE = 0xF6
BMP180_READTEMPCMD = 0x2E
BMP180_READPRESSURECMD = 0x34
)
type BMP180 struct {
Dev i2c.I2CBus
Init bool
Address uint8
oss uint
ac1, ac2, ac3 int16
ac4, ac5, ac6 uint16
b1, b2, mb, mc, md int16
b5 int32
Temp float64
Pressure float64
Altitude float64
}
func (d *BMP180) String() string {
return fmt.Sprintf("Temprature %f", d.Temp)
}
func New(deviceAdress uint8, i2cbus byte) *BMP180 {
deviceBus := i2c.NewI2CBus(i2cbus)
d := &BMP180{
Dev: deviceBus,
Address: deviceAdress,
}
return d
}
// Fetch all values from BMP180
func Fetch(d *BMP180) error {
if !d.Init {
err := calibration(d)
if err != nil {
return err
}
}
// Measure Temprature
if err := d.Dev.WriteByteToReg(d.Address, BMP180_TEMP, BMP180_READTEMPCMD); err != nil {
return err
}
// Get TEMP
ut, err := d.Dev.ReadWordFromReg(d.Address, BMP180_TEMP)
if err != nil {
return err
}
UT := int32(ut)
X1 := ((UT - int32(d.ac6)) * int32(d.ac5)) >> 15
X2 := (int32(d.mc) * 2048) / (X1 + int32(d.md))
B5 := X1 + X2
CT := (B5 + 8) >> 4
d.Temp = float64(CT) * 0.1
return nil
}
func calibration(d *BMP180) error {
ac1, err := d.Dev.ReadWordFromReg(d.Address, BMP180_CALREG_AC1)
if err != nil {
return err
}
d.ac1 = int16(ac1)
ac2, err := d.Dev.ReadWordFromReg(d.Address, BMP180_CALREG_AC2)
if err != nil {
return err
}
d.ac2 = int16(ac2)
ac3, err := d.Dev.ReadWordFromReg(d.Address, BMP180_CALREG_AC3)
if err != nil {
return err
}
d.ac3 = int16(ac3)
ac4, err := d.Dev.ReadWordFromReg(d.Address, BMP180_CALREG_AC4)
if err != nil {
return err
}
d.ac4 = uint16(ac4)
ac5, err := d.Dev.ReadWordFromReg(d.Address, BMP180_CALREG_AC5)
if err != nil {
return err
}
d.ac5 = uint16(ac5)
ac6, err := d.Dev.ReadWordFromReg(d.Address, BMP180_CALREG_AC6)
if err != nil {
return err
}
d.ac6 = uint16(ac6)
b1, err := d.Dev.ReadWordFromReg(d.Address, BMP180_CALREG_B1)
if err != nil {
return err
}
d.b1 = int16(b1)
b2, err := d.Dev.ReadWordFromReg(d.Address, BMP180_CALREG_B2)
if err != nil {
return err
}
d.b2 = int16(b2)
mb, err := d.Dev.ReadWordFromReg(d.Address, BMP180_CALREG_MB)
if err != nil {
return err
}
d.mb = int16(mb)
mc, err := d.Dev.ReadWordFromReg(d.Address, BMP180_CALREG_MC)
if err != nil {
return err
}
d.mc = int16(mc)
md, err := d.Dev.ReadWordFromReg(d.Address, BMP180_CALREG_MD)
if err != nil {
return err
}
d.md = int16(md)
d.Init = true
return nil
}