go-embedded/embd
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bring in the idea of a hardware abstraction layer

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This commit is contained in:
Karan Misra 2014-02-27 04:24:53 +05:30
parent b4de382833
commit b5e2d0acc7
35 changed files with 994 additions and 971 deletions
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45
sensor/us020/us020.go
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@ -6,7 +6,8 @@ import (
"sync"
"time"
"github.com/stianeikeland/go-rpio"
"github.com/kidoman/embd"
"github.com/kidoman/embd/gpio"
)
const (
@ -29,13 +30,10 @@ var NullThermometer = &nullThermometer{}
// US020 represents a US020 ultrasonic range finder.
type US020 struct {
EchoPinNumber, TriggerPinNumber int
EchoPin, TriggerPin gpio.DigitalPin
Thermometer Thermometer
echoPin rpio.Pin
triggerPin rpio.Pin
speedSound float64
initialized bool
@ -46,8 +44,8 @@ type US020 struct {
// New creates a new US020 interface. The bus variable controls
// the I2C bus used to communicate with the device.
func New(e, t int, thermometer Thermometer) *US020 {
return &US020{EchoPinNumber: e, TriggerPinNumber: t, Thermometer: thermometer}
func New(echoPin, triggerPin gpio.DigitalPin, thermometer Thermometer) *US020 {
return &US020{EchoPin: echoPin, TriggerPin: triggerPin, Thermometer: thermometer}
}
func (d *US020) setup() (err error) {
@ -61,11 +59,8 @@ func (d *US020) setup() (err error) {
d.mu.Lock()
defer d.mu.Unlock()
d.echoPin = rpio.Pin(d.EchoPinNumber) // ECHO port on the US020
d.triggerPin = rpio.Pin(d.TriggerPinNumber) // TRIGGER port on the US020
d.echoPin.Input()
d.triggerPin.Output()
d.TriggerPin.SetDir(embd.Out)
d.EchoPin.SetDir(embd.In)
if d.Thermometer == nil {
d.Thermometer = NullThermometer
@ -97,16 +92,24 @@ func (d *US020) Distance() (distance float64, err error) {
}
// Generate a TRIGGER pulse
d.triggerPin.High()
d.TriggerPin.Write(gpio.High)
time.Sleep(pulseDelay)
d.triggerPin.Low()
d.TriggerPin.Write(gpio.Low)
if d.Debug {
log.Print("us020: waiting for echo to go high")
}
// Wait until ECHO goes high
for d.echoPin.Read() == rpio.Low {
for {
v, err := d.EchoPin.Read()
if err != nil {
return 0, err
}
if v != embd.Low {
break
}
}
startTime := time.Now() // Record time when ECHO goes high
@ -116,7 +119,15 @@ func (d *US020) Distance() (distance float64, err error) {
}
// Wait until ECHO goes low
for d.echoPin.Read() == rpio.High {
for {
v, err := d.EchoPin.Read()
if err != nil {
return 0, err
}
if v != embd.High {
break
}
}
duration := time.Since(startTime) // Calculate time lapsed for ECHO to transition from high to low
@ -129,5 +140,5 @@ func (d *US020) Distance() (distance float64, err error) {
// Close.
func (d *US020) Close() {
d.echoPin.Output()
d.EchoPin.SetDir(embd.Out)
}