mirror of
https://github.com/kidoman/embd
synced 2024-12-22 12:50:19 +01:00
266 lines
6.6 KiB
Go
266 lines
6.6 KiB
Go
// Package pca9685 allows interfacing with the pca9685 16-channel, 12-bit PWM Controller through I2C protocol.
|
|
package pca9685
|
|
|
|
import (
|
|
"math"
|
|
"sync"
|
|
"time"
|
|
|
|
"github.com/golang/glog"
|
|
"github.com/kidoman/embd"
|
|
"github.com/kidoman/embd/util"
|
|
)
|
|
|
|
const (
|
|
clockFreq = 25000000
|
|
pwmControlPoints = 4096
|
|
|
|
mode1RegAddr = 0x00
|
|
preScaleRegAddr = 0xFE
|
|
|
|
pwm0OnLowReg = 0x6
|
|
|
|
// inspired by arduino's default freq for analogWrites
|
|
defaultFreq = 490
|
|
)
|
|
|
|
// PCA9685 represents a PCA9685 PWM generator.
|
|
type PCA9685 struct {
|
|
Bus embd.I2CBus
|
|
Addr byte
|
|
Freq int
|
|
|
|
initialized bool
|
|
mu sync.RWMutex
|
|
}
|
|
|
|
// New creates a new PCA9685 interface.
|
|
func New(bus embd.I2CBus, addr byte) *PCA9685 {
|
|
return &PCA9685{
|
|
Bus: bus,
|
|
Addr: addr,
|
|
}
|
|
}
|
|
|
|
func (d *PCA9685) mode1Reg() (byte, error) {
|
|
return d.Bus.ReadByteFromReg(d.Addr, mode1RegAddr)
|
|
}
|
|
|
|
func (d *PCA9685) setup() error {
|
|
d.mu.RLock()
|
|
if d.initialized {
|
|
d.mu.RUnlock()
|
|
return nil
|
|
}
|
|
d.mu.RUnlock()
|
|
|
|
d.mu.Lock()
|
|
defer d.mu.Unlock()
|
|
|
|
mode1Reg, err := d.mode1Reg()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
glog.V(1).Infof("pca9685: read MODE1 Reg [regAddr: %#02x] Value: [%v]", mode1RegAddr, mode1Reg)
|
|
|
|
if err := d.sleep(); err != nil {
|
|
return err
|
|
}
|
|
|
|
if d.Freq == 0 {
|
|
d.Freq = defaultFreq
|
|
}
|
|
preScaleValue := byte(math.Floor(float64(clockFreq/(pwmControlPoints*d.Freq))+float64(0.5)) - 1)
|
|
glog.V(1).Infof("pca9685: calculated prescale value = %#02x", preScaleValue)
|
|
if err := d.Bus.WriteByteToReg(d.Addr, preScaleRegAddr, byte(preScaleValue)); err != nil {
|
|
return err
|
|
}
|
|
glog.V(1).Infof("pca9685: prescale value [%#02x] written to PRE_SCALE Reg [regAddr: %#02x]", preScaleValue, preScaleRegAddr)
|
|
|
|
if err := d.wake(); err != nil {
|
|
return err
|
|
}
|
|
|
|
newmode := ((mode1Reg | 0x01) & 0xDF)
|
|
if err := d.Bus.WriteByteToReg(d.Addr, mode1RegAddr, newmode); err != nil {
|
|
return err
|
|
}
|
|
|
|
glog.V(1).Infof("pca9685: new mode [%#02x] [disabling register auto increment] written to MODE1 Reg [regAddr: %#02x]", newmode, mode1RegAddr)
|
|
|
|
d.initialized = true
|
|
|
|
glog.V(1).Infof("pca9685: driver initialized with pwm freq: %v", d.Freq)
|
|
|
|
return nil
|
|
}
|
|
|
|
// SetPwm sets the ON and OFF time registers for pwm signal shaping.
|
|
// channel: 0-15
|
|
// onTime/offTime: 0-4095
|
|
func (d *PCA9685) SetPwm(channel, onTime, offTime int) error {
|
|
if err := d.setup(); err != nil {
|
|
return err
|
|
}
|
|
|
|
onTimeLowReg := byte(pwm0OnLowReg + (4 * channel))
|
|
|
|
onTimeLow := byte(onTime & 0xFF)
|
|
onTimeHigh := byte(onTime >> 8)
|
|
offTimeLow := byte(offTime & 0xFF)
|
|
offTimeHigh := byte(offTime >> 8)
|
|
|
|
if err := d.Bus.WriteByteToReg(d.Addr, onTimeLowReg, onTimeLow); err != nil {
|
|
return err
|
|
}
|
|
|
|
glog.V(2).Infof("pca9685: writing on-time low [%#02x] to CHAN%v_ON_L reg [reg: %#02x]", onTimeLow, channel, onTimeLowReg)
|
|
|
|
onTimeHighReg := onTimeLowReg + 1
|
|
if err := d.Bus.WriteByteToReg(d.Addr, onTimeHighReg, onTimeHigh); err != nil {
|
|
return err
|
|
}
|
|
glog.V(2).Infof("pca9685: writing on-time high [%#02x] to CHAN%v_ON_H reg [reg: %#02x]", onTimeHigh, channel, onTimeHighReg)
|
|
|
|
offTimeLowReg := onTimeHighReg + 1
|
|
if err := d.Bus.WriteByteToReg(d.Addr, offTimeLowReg, offTimeLow); err != nil {
|
|
return err
|
|
}
|
|
glog.V(2).Infof("pca9685: writing off-time low [%#02x] to CHAN%v_OFF_L reg [reg: %#02x]", offTimeLow, channel, offTimeLowReg)
|
|
|
|
offTimeHighReg := offTimeLowReg + 1
|
|
if err := d.Bus.WriteByteToReg(d.Addr, offTimeHighReg, offTimeHigh); err != nil {
|
|
return err
|
|
}
|
|
glog.V(2).Infof("pca9685: writing off-time high [%#02x] to CHAN%v_OFF_H reg [reg: %#02x]", offTimeHigh, channel, offTimeHighReg)
|
|
|
|
return nil
|
|
}
|
|
|
|
type pwmChannel struct {
|
|
d *PCA9685
|
|
|
|
channel int
|
|
}
|
|
|
|
func (p *pwmChannel) SetMicroseconds(us int) error {
|
|
return p.d.setMicroseconds(p.channel, us)
|
|
}
|
|
|
|
// SetAnalog is a convinience method which allows easy manipulation of the PWM
|
|
// based on a (0-255) range value.
|
|
func (p *pwmChannel) SetAnalog(value byte) error {
|
|
offTime := util.Map(int64(value), 0, 255, 0, pwmControlPoints-1)
|
|
return p.d.SetPwm(p.channel, 0, int(offTime))
|
|
}
|
|
|
|
func (d *PCA9685) ServoChannel(channel int) *pwmChannel {
|
|
return &pwmChannel{d: d, channel: channel}
|
|
}
|
|
|
|
func (d *PCA9685) AnalogChannel(channel int) *pwmChannel {
|
|
return &pwmChannel{d: d, channel: channel}
|
|
}
|
|
|
|
// SetMicroseconds is a convinience method which allows easy servo control.
|
|
func (d *PCA9685) setMicroseconds(channel, us int) error {
|
|
offTime := us * d.Freq * pwmControlPoints / 1000000
|
|
return d.SetPwm(channel, 0, offTime)
|
|
}
|
|
|
|
// Close stops the controller and resets mode and pwm controller registers.
|
|
func (d *PCA9685) Close() error {
|
|
if err := d.setup(); err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := d.sleep(); err != nil {
|
|
return err
|
|
}
|
|
|
|
glog.V(1).Infof("pca9685: reset request received")
|
|
|
|
if err := d.Bus.WriteByteToReg(d.Addr, mode1RegAddr, 0x00); err != nil {
|
|
return err
|
|
}
|
|
|
|
glog.V(1).Infof("pca9685: cleaning up all PWM control registers")
|
|
|
|
for regAddr := 0x06; regAddr <= 0x45; regAddr++ {
|
|
if err := d.Bus.WriteByteToReg(d.Addr, byte(regAddr), 0x00); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
if glog.V(1) {
|
|
glog.Infof("pca9685: done Cleaning up all PWM control registers")
|
|
glog.Infof("pca9685: controller reset")
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func (d *PCA9685) sleep() error {
|
|
glog.V(1).Infof("pca9685: sleep request received")
|
|
|
|
mode1Reg, err := d.mode1Reg()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
sleepmode := (mode1Reg & 0x7F) | 0x10
|
|
if err := d.Bus.WriteByteToReg(d.Addr, mode1RegAddr, sleepmode); err != nil {
|
|
return err
|
|
}
|
|
if glog.V(1) {
|
|
glog.Infof("pca9685: sleep mode [%#02x] written to MODE1 Reg [regAddr: %#02x]", sleepmode, mode1RegAddr)
|
|
glog.Infoln("pca9685: controller set to Sleep mode")
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
// Sleep puts the controller in sleep mode. Does not change the pwm control registers.
|
|
func (d *PCA9685) Sleep() error {
|
|
if err := d.setup(); err != nil {
|
|
return err
|
|
}
|
|
|
|
return d.sleep()
|
|
}
|
|
|
|
func (d *PCA9685) wake() error {
|
|
glog.V(1).Infoln("pca9685: wake request received")
|
|
|
|
mode1Reg, err := d.mode1Reg()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
wakeMode := mode1Reg & 0xEF
|
|
if (mode1Reg & 0x80) == 0x80 {
|
|
if err := d.Bus.WriteByteToReg(d.Addr, mode1RegAddr, wakeMode); err != nil {
|
|
return err
|
|
}
|
|
glog.V(1).Infof("pca9685: wake mode [%#02x] written to MODE1 Reg [regAddr: %#02x]", wakeMode, mode1RegAddr)
|
|
|
|
time.Sleep(500 * time.Microsecond)
|
|
}
|
|
|
|
restartOpCode := wakeMode | 0x80
|
|
if err := d.Bus.WriteByteToReg(d.Addr, mode1RegAddr, restartOpCode); err != nil {
|
|
return err
|
|
}
|
|
glog.V(1).Infof("pca9685: restart mode [%#02x] written to MODE1 Reg [regAddr: %#02x]", restartOpCode, mode1RegAddr)
|
|
|
|
return nil
|
|
}
|
|
|
|
// Wake allows the controller to exit sleep mode and resume with PWM generation.
|
|
func (d *PCA9685) Wake() error {
|
|
if err := d.setup(); err != nil {
|
|
return err
|
|
}
|
|
|
|
return d.wake()
|
|
}
|