Merge pull request #3 from kunalpowar/pca9685

- Added pca9685 package 16-channel, 12-bit PWM controller with I2C
This commit is contained in:
Karan Misra 2014-01-05 00:59:46 -08:00
commit dc12bb631d
5 changed files with 453 additions and 2 deletions

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@ -50,8 +50,16 @@ Use various sensors on the RaspberryPi with Golang (like a ninja!)
[Documentation](http://godoc.org/github.com/kid0m4n/go-rpi/sensor/us020) [Datasheet](http://www.elechouse.com/elechouse/images/product/Digital%20light%20Sensor/bh1750fvi-e.pdf)
##Interfaces
## Interfaces
###Keypad(4x3)
### Keypad(4x3)
[Product Page](http://www.adafruit.com/products/419#Learn)
## Controllers
### PCA9685
16-channel, 12-bit PWM Controller with I2C protocol
[Datasheet] (http://www.adafruit.com/datasheets/PCA9685.pdf)
[Product Page] (http://www.adafruit.com/products/815)

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// Package pca9685 allows interfacing with the pca9685 16-channel, 12-bit PWM Controller through I2C protocol.
package pca9685
import (
"log"
"math"
"sync"
"time"
"github.com/kid0m4n/go-rpi/i2c"
)
const (
clockFreq = 25000000
pwmControlPoints = 4096
mode1RegAddr = 0x00
preScaleRegAddr = 0xFE
pwm0OnLowReg = 0x6
)
// A PCA9685 interface implements access to the controller.
type PCA9685 interface {
// SetPwm sets the ON and OFF time registers for pwm signal shaping.
// n: channel 0-15
// onTime/offTime: 0-4095
SetPwm(n int, onTime int, offTime int) error
// Wake allows the controller to exit sleep mode and resume with PWM generation.
Wake() error
// Sleep puts the controller in sleep mode. Does not change the pwm control registers.
Sleep() error
// Close stops the controller and resets mode and pwm controller registers.
Close() error
// SetDebug is used to enable logging (debug mode).
SetDebug(status bool)
}
type pca9685 struct {
bus i2c.Bus
addr byte
freq int
initialized bool
mu sync.RWMutex
debug bool
}
// The pca9685 controller supports pwm frequencies from 40Hz to 1000Hz
// New creates a new PCA9685 interface.
func New(bus i2c.Bus, addr byte, freq int) PCA9685 {
return &pca9685{bus: bus, addr: addr, freq: freq}
}
// SetDebug is used to enable logging (debug mode).
func (d *pca9685) SetDebug(status bool) {
d.debug = status
}
func (d *pca9685) mode1Reg() (byte, error) {
return d.bus.ReadByteFromReg(d.addr, mode1RegAddr)
}
func (d *pca9685) setup() (err error) {
d.mu.RLock()
if d.initialized {
d.mu.RUnlock()
return
}
d.mu.RUnlock()
d.mu.Lock()
defer d.mu.Unlock()
preScaleValue := byte(math.Floor(float64(clockFreq/(pwmControlPoints*d.freq))+float64(0.5)) - 1)
if d.debug {
log.Printf("pca9685: calculated Prescale value = %#02x", preScaleValue)
}
mode1Reg, err := d.mode1Reg()
if err != nil {
return
}
if d.debug {
log.Printf("pca9685: read MODE1 Reg [regAddr: %#02x] Value: [%v]", mode1RegAddr, mode1Reg)
}
if err = d.sleep(); err != nil {
return
}
if err = d.bus.WriteToReg(d.addr, preScaleRegAddr, byte(preScaleValue)); err != nil {
return
}
if d.debug {
log.Printf("pca9685: prescale value [%#02x] written to PRE_SCALE Reg [regAddr: %#02x]", preScaleValue, preScaleRegAddr)
}
if err = d.wake(); err != nil {
return
}
newmode := ((mode1Reg | 0x01) & 0xDF)
if err = d.bus.WriteToReg(d.addr, mode1RegAddr, newmode); err != nil {
return
}
if d.debug {
log.Printf("pca9685: new mode [%#02x] [disabling register auto increment] written to MODE1 Reg [regAddr: %#02x]", newmode, mode1RegAddr)
}
d.initialized = true
if d.debug {
log.Printf("pca9685: driver initialized with pwm freq: %v", d.freq)
}
return
}
// SetPwm sets the ON and OFF time registers for pwm signal shaping.
// channel: 0-15
// onTime/offTime: 0-4095
func (d *pca9685) SetPwm(n, onTime, offTime int) (err error) {
if err = d.setup(); err != nil {
return
}
onTimeLowReg := byte(pwm0OnLowReg + (4 * n))
onTimeLow := byte(onTime & 0xFF)
onTimeHigh := byte(onTime >> 8)
offTimeLow := byte(offTime & 0xFF)
offTimeHigh := byte(offTime >> 8)
if err = d.bus.WriteToReg(d.addr, onTimeLowReg, onTimeLow); err != nil {
return
}
if d.debug {
log.Printf("pca9685: writing On-Time Low [%#02x] to CHAN%v_ON_L reg [RegAddr: %#02x]", onTimeLow, n, onTimeLowReg)
}
onTimeHighReg := onTimeLowReg + 1
if err = d.bus.WriteToReg(d.addr, onTimeHighReg, onTimeHighReg); err != nil {
return
}
if d.debug {
log.Printf("pca9685: writing On-Time High [%#02x] to CHAN%v_ON_H reg [RegAddr: %#02x]", onTimeHigh, n, onTimeHighReg)
}
offTimeLowReg := onTimeHighReg + 1
if err = d.bus.WriteToReg(d.addr, offTimeLowReg, offTimeLow); err != nil {
return
}
if d.debug {
log.Printf("pca9685: writing Off-Time Low [%#02x] to CHAN%v_OFF_L reg [RegAddr: %#02x]", offTimeLow, n, offTimeLowReg)
}
offTimeHighReg := offTimeLowReg + 1
if err = d.bus.WriteToReg(d.addr, offTimeHighReg, offTimeHigh); err != nil {
return
}
if d.debug {
log.Printf("pca9685: writing Off-Time High [%#02x] to CHAN%v_OFF_H reg [RegAddr: %#02x]", offTimeHigh, n, offTimeHighReg)
}
return
}
// Close stops the controller and resets mode and pwm controller registers.
func (d *pca9685) Close() (err error) {
if err = d.setup(); err != nil {
return
}
if err = d.sleep(); err != nil {
return
}
if d.debug {
log.Println("pca9685: reset request received")
}
if err = d.bus.WriteToReg(d.addr, mode1RegAddr, 0x00); err != nil {
return
}
if d.debug {
log.Printf("pca9685: cleaning up all PWM control registers")
}
for regAddr := 0x0; regAddr <= 0x45; regAddr++ {
if err = d.bus.WriteToReg(d.addr, byte(regAddr), 0x00); err != nil {
return
}
}
if d.debug {
log.Printf("pca9685: done Cleaning up all PWM control registers")
}
if d.debug {
log.Println("pca9685: controller reset")
}
return
}
func (d *pca9685) sleep() (err error) {
if d.debug {
log.Println("pca9685: sleep request received")
}
mode1Reg, err := d.mode1Reg()
if err != nil {
return
}
sleepmode := (mode1Reg & 0x7F) | 0x10
if err = d.bus.WriteToReg(d.addr, mode1RegAddr, sleepmode); err != nil {
return
}
if d.debug {
log.Printf("pca9685: sleep mode [%#02x] written to MODE1 Reg [regAddr: %#02x]", sleepmode, mode1RegAddr)
}
if d.debug {
log.Println("pca9685: controller set to Sleep mode")
}
return
}
// Sleep puts the controller in sleep mode. Does not change the pwm control registers.
func (d *pca9685) Sleep() (err error) {
if err = d.setup(); err != nil {
return
}
return d.sleep()
}
func (d *pca9685) wake() (err error) {
if d.debug {
log.Println("pca9685: wake request received")
}
mode1Reg, err := d.mode1Reg()
if err != nil {
return
}
wakeMode := mode1Reg & 0xEF
if (mode1Reg & 0x80) == 0x80 {
if err = d.bus.WriteToReg(d.addr, mode1RegAddr, wakeMode); err != nil {
return
}
if d.debug {
log.Printf("pca9685: wake mode [%#02x] written to MODE1 Reg [regAddr: %#02x]", wakeMode, mode1RegAddr)
}
time.Sleep(500 * time.Microsecond)
}
restartOpCode := wakeMode | 0x80
if err = d.bus.WriteToReg(d.addr, mode1RegAddr, restartOpCode); err != nil {
return
}
if d.debug {
log.Printf("pca9685: restart mode [%#02x] written to MODE1 Reg [regAddr: %#02x]", restartOpCode, mode1RegAddr)
}
return
}
// Wake allows the controller to exit sleep mode and resume with PWM generation.
func (d *pca9685) Wake() (err error) {
if err = d.setup(); err != nil {
return
}
return d.wake()
}

61
motion/servo/servo.go Normal file
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// Package servo allows control of servos using a PWM controller.
package servo
import (
"log"
)
// A PWM interface implements access to a pwm controller.
type PWM interface {
SetPwm(n int, onTime int, offTime int) error
}
// A SERVO interface implements access to the servo.
type Servo interface {
SetAngle(angle int) error
SetDebug(v bool)
}
type servo struct {
pwm PWM
freq int
n int
minms, maxms float64
debug bool
}
// New creates a new SERVO interface.
// pwm: instance of a PWM controller.
// freq: Frequency of pwm signal (typically 50Hz)
// n: PWM channel of the pwm controller to be used
// minms: Pulse width corresponding to servo position of 0deg
// maxms: Pulse width corresponding to servo position of 180deg
func New(pwm PWM, freq int, n int, minms, maxms float64) Servo {
return &servo{
pwm: pwm,
freq: freq,
n: n,
minms: minms,
maxms: maxms,
}
}
// SetDebug is used to enable logging (debug mode).
func (s *servo) SetDebug(v bool) {
s.debug = v
}
// SetAngle sets the servo angle.
func (s *servo) SetAngle(angle int) error {
ms := s.minms + float64(angle)*(s.maxms-s.minms)/180
offTime := int(ms * float64(s.freq) * 4096 / 1000)
if s.debug {
log.Printf("servo: given angle %v calculated ms %2.2f offTime %v", angle, ms, offTime)
}
return s.pwm.SetPwm(s.n, 0, offTime)
}

46
samples/pca9685.go Normal file
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package main
import (
"log"
"os"
"os/signal"
"time"
"github.com/kid0m4n/go-rpi/controller/pca9685"
"github.com/kid0m4n/go-rpi/i2c"
)
func main() {
bus, err := i2c.NewBus(1)
if err != nil {
log.Panic(err)
}
pca9685 := pca9685.New(bus, 0x41, 1000)
pca9685.SetDebug(true)
defer pca9685.Close()
if err := pca9685.SetPwm(15, 0, 1000); err != nil {
log.Panic(err)
}
c := make(chan os.Signal, 1)
signal.Notify(c, os.Interrupt, os.Kill)
timer := time.Tick(2 * time.Second)
sleeping := false
for {
select {
case <-timer:
sleeping = !sleeping
if sleeping {
pca9685.Sleep()
} else {
pca9685.Wake()
}
case <-c:
return
}
}
}

51
samples/servo.go Normal file
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package main
import (
"log"
"os"
"os/signal"
"time"
"github.com/kid0m4n/go-rpi/controller/pca9685"
"github.com/kid0m4n/go-rpi/i2c"
"github.com/kid0m4n/go-rpi/motion/servo"
)
func main() {
bus, err := i2c.NewBus(1)
if err != nil {
log.Panic(err)
}
pwm := pca9685.New(bus, 0x42, 50)
defer pwm.Close()
servo := servo.New(pwm, 50, 0, 1, 2.5)
servo.SetDebug(true)
c := make(chan os.Signal, 1)
signal.Notify(c, os.Interrupt, os.Kill)
turnTimer := time.Tick(500 * time.Millisecond)
left := true
servo.SetAngle(90)
defer func() {
servo.SetAngle(90)
}()
for {
select {
case <-turnTimer:
left = !left
switch left {
case true:
servo.SetAngle(70)
case false:
servo.SetAngle(110)
}
case <-c:
return
}
}
}