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initial support for accel ADXL345
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@conejoninja
conejoninja committed Jan 16, 2018
1 parent 6fb9c39 commit 6ad9dfc
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275 changes: 275 additions & 0 deletions drivers/i2c/ADXL345.go
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package i2c

import (
"encoding/binary"

"github.com/pkg/errors"
"gobot.io/x/gobot"
)

const ADXL345AddressLow = 0x53
const ADXL345AddressHigh = 0x1D

const (
// Data rate
ADXL345_RATE_3200HZ = 0x0F // 3200 Hz
ADXL345_RATE_1600HZ = 0x0E // 1600 Hz
ADXL345_RATE_800HZ = 0x0D // 800 Hz
ADXL345_RATE_400HZ = 0x0C // 400 Hz
ADXL345_RATE_200HZ = 0x0B // 200 Hz
ADXL345_RATE_100HZ = 0x0A // 100 Hz
ADXL345_RATE_50HZ = 0x09 // 50 Hz
ADXL345_RATE_25HZ = 0x08 // 25 Hz
ADXL345_RATE_12_5HZ = 0x07 // 12.5 Hz
ADXL345_RATE_6_25HZ = 0x06 // 6.25 Hz
ADXL345_RATE_3_13HZ = 0x05 // 3.13 Hz
ADXL345_RATE_1_56HZ = 0x04 // 1.56 Hz
ADXL345_RATE_0_78HZ = 0x03 // 0.78 Hz
ADXL345_RATE_0_39HZ = 0x02 // 0.39 Hz
ADXL345_RATE_0_20HZ = 0x01 // 0.20 Hz
ADXL345_RATE_0_10HZ = 0x00 // 0.10 Hz

// Data range
ADXL345_RANGE_2G = 0x00 // +-2 g
ADXL345_RANGE_4G = 0x01 // +-4 g
ADXL345_RANGE_8G = 0x02 // +-8 g
ADXL345_RANGE_16G = 0x03 // +-16 g)

ADXL345_REG_DEVID = 0x00 // R, 11100101, Device ID
ADXL345_REG_THRESH_TAP = 0x1D // R/W, 00000000, Tap threshold
ADXL345_REG_OFSX = 0x1E // R/W, 00000000, X-axis offset
ADXL345_REG_OFSY = 0x1F // R/W, 00000000, Y-axis offset
ADXL345_REG_OFSZ = 0x20 // R/W, 00000000, Z-axis offset
ADXL345_REG_DUR = 0x21 // R/W, 00000000, Tap duration
ADXL345_REG_LATENT = 0x22 // R/W, 00000000, Tap latency
ADXL345_REG_WINDOW = 0x23 // R/W, 00000000, Tap window
ADXL345_REG_THRESH_ACT = 0x24 // R/W, 00000000, Activity threshold
ADXL345_REG_THRESH_INACT = 0x25 // R/W, 00000000, Inactivity threshold
ADXL345_REG_TIME_INACT = 0x26 // R/W, 00000000, Inactivity time
ADXL345_REG_ACT_INACT_CTL = 0x27 // R/W, 00000000, Axis enable control for activity and inactiv ity detection
ADXL345_REG_THRESH_FF = 0x28 // R/W, 00000000, Free-fall threshold
ADXL345_REG_TIME_FF = 0x29 // R/W, 00000000, Free-fall time
ADXL345_REG_TAP_AXES = 0x2A // R/W, 00000000, Axis control for single tap/double tap
ADXL345_REG_ACT_TAP_STATUS = 0x2B // R, 00000000, Source of single tap/double tap
ADXL345_REG_BW_RATE = 0x2C // R/W, 00001010, Data rate and power mode control
ADXL345_REG_POWER_CTL = 0x2D // R/W, 00000000, Power-saving features control
ADXL345_REG_INT_ENABLE = 0x2E // R/W, 00000000, Interrupt enable control
ADXL345_REG_INT_MAP = 0x2F // R/W, 00000000, Interrupt mapping control
ADXL345_REG_INT_SOUCE = 0x30 // R, 00000010, Source of interrupts
ADXL345_REG_DATA_FORMAT = 0x31 // R/W, 00000000, Data format control
ADXL345_REG_DATAX0 = 0x32 // R, 00000000, X-Axis Data 0
ADXL345_REG_DATAX1 = 0x33 // R, 00000000, X-Axis Data 1
ADXL345_REG_DATAY0 = 0x34 // R, 00000000, Y-Axis Data 0
ADXL345_REG_DATAY1 = 0x35 // R, 00000000, Y-Axis Data 1
ADXL345_REG_DATAZ0 = 0x36 // R, 00000000, Z-Axis Data 0
ADXL345_REG_DATAZ1 = 0x37 // R, 00000000, Z-Axis Data 1
ADXL345_REG_FIFO_CTL = 0x38 // R/W, 00000000, FIFO control
ADXL345_REG_FIFO_STATUS = 0x39 // R, 00000000, FIFO status
)

type ADXL345Driver struct {
name string
connector Connector
connection Connection

powerCtl adxl345PowerCtl
dataFormat adxl345DataFormat
bwRate adxl345BwRate

x, y, z float64
rawX, rawY, rawZ int16

Config
}

type adxl345PowerCtl struct {
Link uint8
AutoSleep uint8
Measure uint8
Sleep uint8
WakeUp uint8
}

type adxl345DataFormat struct {
SelfTest uint8
SPI uint8
IntInvert uint8
FullRes uint8
Justify uint8
Range uint8
}

type adxl345BwRate struct {
LowPower uint8
Rate uint8
}

// NewADXL345Driver creates a new driver with specified i2c interface
// Params:
// conn Connector - the Adaptor to use with this Driver
//
// Optional params:
// i2c.WithBus(int): bus to use with this driver
// i2c.WithAddress(int): address to use with this driver
//
func NewADXL345Driver(a Connector, options ...func(Config)) *ADXL345Driver {
m := &ADXL345Driver{
name: gobot.DefaultName("ADXL345"),
connector: a,
powerCtl: adxl345PowerCtl{
Measure: 1,
},
dataFormat: adxl345DataFormat{
Range: ADXL345_RANGE_2G,
},
bwRate: adxl345BwRate{
LowPower: 1,
Rate: ADXL345_RATE_100HZ,
},
Config: NewConfig(),
}

for _, option := range options {
option(m)
}

// TODO: add commands for API
return m
}

// Name returns the Name for the Driver
func (h *ADXL345Driver) Name() string { return h.name }

// SetName sets the Name for the Driver
func (h *ADXL345Driver) SetName(n string) { h.name = n }

// Connection returns the connection for the Driver
func (h *ADXL345Driver) Connection() gobot.Connection { return h.connector.(gobot.Connection) }

// Start initialized the adxl345
func (h *ADXL345Driver) Start() (err error) {
bus := h.GetBusOrDefault(h.connector.GetDefaultBus())
address := h.GetAddressOrDefault(ADXL345AddressLow)

h.connection, err = h.connector.GetConnection(address, bus)
if err != nil {
return err
}

if _, err := h.connection.Write([]byte{ADXL345_REG_BW_RATE, h.bwRate.toByte()}); err != nil {
return err
}

if _, err := h.connection.Write([]byte{ADXL345_REG_POWER_CTL, h.powerCtl.toByte()}); err != nil {
return err
}

if _, err := h.connection.Write([]byte{ADXL345_REG_DATA_FORMAT, h.dataFormat.toByte()}); err != nil {
return err
}

return
}

// Stop adxl345
func (h *ADXL345Driver) Stop() (err error) {
if _, err := h.connection.Write([]byte{ADXL345_REG_POWER_CTL, 0}); err != nil {
return err
}

return
}

// Halt returns true if devices is halted successfully
func (h *ADXL345Driver) Halt() (err error) {
h.Stop()
return
}

// XYZ returns the adjusted x, y and z axis from the adxl345
func (h *ADXL345Driver) XYZ() (x float64, y float64, z float64) {
h.update()
return h.x, h.y, h.z
}

// XYZ returns the raw x,y and z axis from the adxl345
func (h *ADXL345Driver) RawXYZ() (x int16, y int16, z int16) {
h.update()
return h.rawX, h.rawY, h.rawZ
}

// update the cached values for the axis to avoid errors if the connection is not available (polling too frequently)
func (h *ADXL345Driver) update() (err error) {

if h.connection == nil {
return errors.New("connection not available")
}

h.connection.Write([]byte{ADXL345_REG_DATAX0})
buf := []byte{0, 0, 0, 0, 0, 0}

_, err = h.connection.Read(buf)
if err != nil {
return
}

h.rawX = int16(binary.LittleEndian.Uint16(buf[0:2]))
h.rawY = int16(binary.LittleEndian.Uint16(buf[2:4]))
h.rawZ = int16(binary.LittleEndian.Uint16(buf[4:6]))

h.x = h.dataFormat.ConvertToSI(h.rawX)
h.y = h.dataFormat.ConvertToSI(h.rawY)
h.z = h.dataFormat.ConvertToSI(h.rawZ)

return
}

// ConvertToSI adjusts the raw values from the adxl345 with the range configuration
func (d *adxl345DataFormat) ConvertToSI(rawValue int16) float64 {
switch d.Range {
case ADXL345_RANGE_2G:
return float64(rawValue) * 2 / 512
case ADXL345_RANGE_4G:
return float64(rawValue) * 4 / 512
case ADXL345_RANGE_8G:
return float64(rawValue) * 8 / 512
case ADXL345_RANGE_16G:
return float64(rawValue) * 16 / 512
default:
return 0
}
}

// toByte returns a byte from the powerCtl configuration
func (p *adxl345PowerCtl) toByte() (bits uint8) {
bits = 0x00
bits = bits | (p.Link << 5)
bits = bits | (p.AutoSleep << 4)
bits = bits | (p.Measure << 3)
bits = bits | (p.Sleep << 2)
bits = bits | p.WakeUp

return bits
}

// toByte returns a byte from the dataFormat configuration
func (d *adxl345DataFormat) toByte() (bits uint8) {
bits = 0x00
bits = bits | (d.SelfTest << 7)
bits = bits | (d.SPI << 6)
bits = bits | (d.IntInvert << 5)
bits = bits | (d.FullRes << 3)
bits = bits | (d.Justify << 2)
bits = bits | d.Range

return bits
}

// toByte returns a byte from the bwRate configuration
func (b *adxl345BwRate) toByte() (bits uint8) {
bits = 0x00
bits = bits | (b.LowPower << 4)
bits = bits | b.Rate

return bits
}

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