274 lines
7.5 KiB
Go
274 lines
7.5 KiB
Go
package i2c
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import (
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"strconv"
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"time"
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"gobot.io/x/gobot"
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)
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const pca9685Address = 0x40
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const (
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PCA9685_MODE1 = 0x00
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PCA9685_MODE2 = 0x01
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PCA9685_PRESCALE = 0xFE
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PCA9685_SUBADR1 = 0x02
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PCA9685_SUBADR2 = 0x03
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PCA9685_SUBADR3 = 0x04
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PCA9685_LED0_ON_L = 0x06
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PCA9685_LED0_ON_H = 0x07
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PCA9685_LED0_OFF_L = 0x08
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PCA9685_LED0_OFF_H = 0x09
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PCA9685_ALLLED_ON_L = 0xFA
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PCA9685_ALLLED_ON_H = 0xFB
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PCA9685_ALLLED_OFF_L = 0xFC
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PCA9685_ALLLED_OFF_H = 0xFD
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PCA9685_RESTART = 0x80
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PCA9685_SLEEP = 0x10
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PCA9685_ALLCALL = 0x01
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PCA9685_INVRT = 0x10
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PCA9685_OUTDRV = 0x04
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)
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// PCA9685Driver is a Gobot Driver for the PCA9685 16-channel 12-bit PWM/Servo controller.
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//
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// For example, here is the Adafruit board that uses this chip:
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// https://www.adafruit.com/product/815
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//
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type PCA9685Driver struct {
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name string
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connector Connector
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connection Connection
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Config
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gobot.Commander
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}
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// NewPCA9685Driver creates a new driver with specified i2c interface
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// Params:
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// conn Connector - the Adaptor to use with this Driver
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//
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// Optional params:
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// i2c.WithBus(int): bus to use with this driver
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// i2c.WithAddress(int): address to use with this driver
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//
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func NewPCA9685Driver(a Connector, options ...func(Config)) *PCA9685Driver {
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p := &PCA9685Driver{
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name: gobot.DefaultName("PCA9685"),
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connector: a,
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Config: NewConfig(),
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Commander: gobot.NewCommander(),
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}
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for _, option := range options {
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option(p)
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}
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p.AddCommand("PwmWrite", func(params map[string]interface{}) interface{} {
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pin := params["pin"].(string)
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val, _ := strconv.Atoi(params["val"].(string))
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return p.PwmWrite(pin, byte(val))
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})
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p.AddCommand("ServoWrite", func(params map[string]interface{}) interface{} {
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pin := params["pin"].(string)
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val, _ := strconv.Atoi(params["val"].(string))
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return p.ServoWrite(pin, byte(val))
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})
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p.AddCommand("SetPWM", func(params map[string]interface{}) interface{} {
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channel, _ := strconv.Atoi(params["channel"].(string))
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on, _ := strconv.Atoi(params["on"].(string))
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off, _ := strconv.Atoi(params["off"].(string))
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return p.SetPWM(channel, uint16(on), uint16(off))
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})
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p.AddCommand("SetPWMFreq", func(params map[string]interface{}) interface{} {
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freq, _ := strconv.ParseFloat(params["freq"].(string), 32)
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return p.SetPWMFreq(float32(freq))
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})
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return p
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}
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// Name returns the Name for the Driver
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func (p *PCA9685Driver) Name() string { return p.name }
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// SetName sets the Name for the Driver
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func (p *PCA9685Driver) SetName(n string) { p.name = n }
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// Connection returns the connection for the Driver
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func (p *PCA9685Driver) Connection() gobot.Connection { return p.connector.(gobot.Connection) }
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// Start initializes the pca9685
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func (p *PCA9685Driver) Start() (err error) {
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bus := p.GetBusOrDefault(p.connector.GetDefaultBus())
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address := p.GetAddressOrDefault(pca9685Address)
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p.connection, err = p.connector.GetConnection(address, bus)
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if err != nil {
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return err
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}
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if err := p.SetAllPWM(0, 0); err != nil {
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return err
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}
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if _, err := p.connection.Write([]byte{PCA9685_MODE2, PCA9685_OUTDRV}); err != nil {
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return err
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}
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if _, err := p.connection.Write([]byte{PCA9685_MODE1, PCA9685_ALLCALL}); err != nil {
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return err
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}
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time.Sleep(5 * time.Millisecond)
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if _, err := p.connection.Write([]byte{byte(PCA9685_MODE1)}); err != nil {
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return err
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}
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oldmode, err := p.connection.ReadByte()
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if err != nil {
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return err
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}
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oldmode = oldmode &^ byte(PCA9685_SLEEP)
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if _, err := p.connection.Write([]byte{PCA9685_MODE1, oldmode}); err != nil {
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return err
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}
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time.Sleep(5 * time.Millisecond)
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return
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}
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// Halt stops the device
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func (p *PCA9685Driver) Halt() (err error) {
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_, err = p.connection.Write([]byte{PCA9685_ALLLED_OFF_H, 0x10})
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return
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}
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// SetPWM sets a specific channel to a pwm value from 0-4096.
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// Params:
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// channel int - the channel to send the pulse
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// on uint16 - the time to start the pulse
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// off uint16 - the time to stop the pulse
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//
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// Most typically you set "on" to a zero value, and then set "off" to your desired duty.
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//
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func (p *PCA9685Driver) SetPWM(channel int, on uint16, off uint16) (err error) {
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if _, err := p.connection.Write([]byte{byte(PCA9685_LED0_ON_L + 4*channel), byte(on) & 0xFF}); err != nil {
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return err
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}
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if _, err := p.connection.Write([]byte{byte(PCA9685_LED0_ON_H + 4*channel), byte(on >> 8)}); err != nil {
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return err
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}
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if _, err := p.connection.Write([]byte{byte(PCA9685_LED0_OFF_L + 4*channel), byte(off) & 0xFF}); err != nil {
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return err
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}
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if _, err := p.connection.Write([]byte{byte(PCA9685_LED0_OFF_H + 4*channel), byte(off >> 8)}); err != nil {
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return err
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}
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return
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}
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// SetAllPWM sets all channels to a pwm value from 0-4096.
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// Params:
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// on uint16 - the time to start the pulse
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// off uint16 - the time to stop the pulse
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//
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// Most typically you set "on" to a zero value, and then set "off" to your desired duty.
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//
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func (p *PCA9685Driver) SetAllPWM(on uint16, off uint16) (err error) {
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if _, err := p.connection.Write([]byte{byte(PCA9685_ALLLED_ON_L), byte(on) & 0xFF}); err != nil {
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return err
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}
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if _, err := p.connection.Write([]byte{byte(PCA9685_ALLLED_ON_H), byte(on >> 8)}); err != nil {
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return err
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}
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if _, err := p.connection.Write([]byte{byte(PCA9685_ALLLED_OFF_L), byte(off) & 0xFF}); err != nil {
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return err
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}
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if _, err := p.connection.Write([]byte{byte(PCA9685_ALLLED_OFF_H), byte(off >> 8)}); err != nil {
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return err
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}
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return
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}
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// SetPWMFreq sets the PWM frequency in Hz
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func (p *PCA9685Driver) SetPWMFreq(freq float32) error {
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// IC oscillator frequency is 25 MHz
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var prescalevel float32 = 25000000
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// Find frequency of PWM waveform
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prescalevel /= 4096
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// Ratio between desired frequency and maximum
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prescalevel /= freq
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prescalevel -= 1
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// Round value to nearest whole
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prescale := byte(prescalevel + 0.5)
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if _, err := p.connection.Write([]byte{byte(PCA9685_MODE1)}); err != nil {
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return err
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}
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oldmode, err := p.connection.ReadByte()
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if err != nil {
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return err
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}
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// Put oscillator in sleep mode, clear bit 7 here to avoid overwriting
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// previous setting
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newmode := (oldmode & 0x7F) | 0x10
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if _, err := p.connection.Write([]byte{byte(PCA9685_MODE1), byte(newmode)}); err != nil {
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return err
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}
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// Write prescaler value
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if _, err := p.connection.Write([]byte{byte(PCA9685_PRESCALE), prescale}); err != nil {
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return err
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}
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// Put back to old settings
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if _, err := p.connection.Write([]byte{byte(PCA9685_MODE1), byte(oldmode)}); err != nil {
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return err
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}
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time.Sleep(5 * time.Millisecond)
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// Enable response to All Call address, enable auto-increment, clear restart
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if _, err := p.connection.Write([]byte{byte(PCA9685_MODE1), byte(oldmode | 0x80)}); err != nil {
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return err
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}
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return nil
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}
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// PwmWrite writes a PWM signal to the specified channel aka "pin".
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// Value values are from 0-255, to conform to the PwmWriter interface.
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// If you need finer control, please look at SetPWM().
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//
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func (p *PCA9685Driver) PwmWrite(pin string, val byte) (err error) {
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i, err := strconv.Atoi(pin)
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if err != nil {
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return
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}
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v := gobot.ToScale(gobot.FromScale(float64(val), 0, 255), 0, 4096)
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return p.SetPWM(i, 0, uint16(v))
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}
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// ServoWrite writes a servo signal to the specified channel aka "pin".
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// Valid values are from 0-180, to conform to the ServoWriter interface.
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// If you need finer control, please look at SetPWM().
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//
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func (p *PCA9685Driver) ServoWrite(pin string, val byte) (err error) {
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i, err := strconv.Atoi(pin)
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if err != nil {
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return
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}
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v := gobot.ToScale(gobot.FromScale(float64(val), 0, 180), 200, 500)
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return p.SetPWM(i, 0, uint16(v))
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}
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