145 lines
3.7 KiB
Go
145 lines
3.7 KiB
Go
package i2c
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import (
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"github.com/hybridgroup/gobot"
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"bytes"
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"encoding/binary"
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"time"
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)
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const mpl115a2Address = 0x60
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var _ gobot.Driver = (*MPL115A2Driver)(nil)
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const MPL115A2_REGISTER_PRESSURE_MSB = 0x00
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const MPL115A2_REGISTER_PRESSURE_LSB = 0x01
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const MPL115A2_REGISTER_TEMP_MSB = 0x02
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const MPL115A2_REGISTER_TEMP_LSB = 0x03
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const MPL115A2_REGISTER_A0_COEFF_MSB = 0x04
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const MPL115A2_REGISTER_A0_COEFF_LSB = 0x05
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const MPL115A2_REGISTER_B1_COEFF_MSB = 0x06
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const MPL115A2_REGISTER_B1_COEFF_LSB = 0x07
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const MPL115A2_REGISTER_B2_COEFF_MSB = 0x08
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const MPL115A2_REGISTER_B2_COEFF_LSB = 0x09
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const MPL115A2_REGISTER_C12_COEFF_MSB = 0x0A
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const MPL115A2_REGISTER_C12_COEFF_LSB = 0x0B
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const MPL115A2_REGISTER_STARTCONVERSION = 0x12
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type MPL115A2Driver struct {
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name string
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connection I2c
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interval time.Duration
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gobot.Eventer
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A0 float32
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B1 float32
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B2 float32
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C12 float32
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Pressure float32
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Temperature float32
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}
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// NewMPL115A2Driver creates a new driver with specified i2c interface
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func NewMPL115A2Driver(a I2c, v ...time.Duration) *MPL115A2Driver {
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m := &MPL115A2Driver{
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name: "MPL115A2",
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connection: a,
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Eventer: gobot.NewEventer(),
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interval: 10 * time.Millisecond,
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}
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if len(v) > 0 {
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m.interval = v[0]
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}
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m.AddEvent(Error)
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return m
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}
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func (h *MPL115A2Driver) Name() string { return h.name }
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func (h *MPL115A2Driver) SetName(n string) { h.name = n }
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func (h *MPL115A2Driver) Connection() gobot.Connection { return h.connection.(gobot.Connection) }
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// Start writes initialization bytes and reads from adaptor
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// using specified interval to accelerometer andtemperature data
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func (h *MPL115A2Driver) Start() (err error) {
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var temperature uint16
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var pressure uint16
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var pressureComp float32
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if err := h.initialization(); err != nil {
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return err
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}
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go func() {
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for {
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if err := h.connection.I2cWrite(mpl115a2Address, []byte{MPL115A2_REGISTER_STARTCONVERSION, 0}); err != nil {
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h.Publish(h.Event(Error), err)
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continue
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}
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time.Sleep(5 * time.Millisecond)
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if err := h.connection.I2cWrite(mpl115a2Address, []byte{MPL115A2_REGISTER_PRESSURE_MSB}); err != nil {
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h.Publish(h.Event(Error), err)
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continue
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}
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ret, err := h.connection.I2cRead(mpl115a2Address, 4)
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if err != nil {
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h.Publish(h.Event(Error), err)
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continue
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}
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if len(ret) == 4 {
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buf := bytes.NewBuffer(ret)
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binary.Read(buf, binary.BigEndian, &pressure)
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binary.Read(buf, binary.BigEndian, &temperature)
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temperature = temperature >> 6
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pressure = pressure >> 6
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pressureComp = float32(h.A0) + (float32(h.B1)+float32(h.C12)*float32(temperature))*float32(pressure) + float32(h.B2)*float32(temperature)
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h.Pressure = (65.0/1023.0)*pressureComp + 50.0
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h.Temperature = ((float32(temperature) - 498.0) / -5.35) + 25.0
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}
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time.Sleep(h.interval)
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}
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}()
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return
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}
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// Halt returns true if devices is halted successfully
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func (h *MPL115A2Driver) Halt() (err error) { return }
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func (h *MPL115A2Driver) initialization() (err error) {
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var coA0 int16
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var coB1 int16
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var coB2 int16
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var coC12 int16
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if err = h.connection.I2cStart(mpl115a2Address); err != nil {
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return
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}
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if err = h.connection.I2cWrite(mpl115a2Address, []byte{MPL115A2_REGISTER_A0_COEFF_MSB}); err != nil {
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return
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}
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ret, err := h.connection.I2cRead(mpl115a2Address, 8)
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if err != nil {
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return
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}
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buf := bytes.NewBuffer(ret)
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binary.Read(buf, binary.BigEndian, &coA0)
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binary.Read(buf, binary.BigEndian, &coB1)
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binary.Read(buf, binary.BigEndian, &coB2)
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binary.Read(buf, binary.BigEndian, &coC12)
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coC12 = coC12 >> 2
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h.A0 = float32(coA0) / 8.0
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h.B1 = float32(coB1) / 8192.0
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h.B2 = float32(coB2) / 16384.0
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h.C12 = float32(coC12) / 4194304.0
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return
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}
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