mirror of
https://github.com/kidoman/embd
synced 2024-12-22 12:50:19 +01:00
315 lines
6.6 KiB
Go
315 lines
6.6 KiB
Go
// Package tmp006 allows interfacing with the TMP006 thermopile.
|
|
package tmp006
|
|
|
|
import (
|
|
"errors"
|
|
"fmt"
|
|
"math"
|
|
"sync"
|
|
"time"
|
|
|
|
"github.com/golang/glog"
|
|
"github.com/kidoman/embd"
|
|
)
|
|
|
|
const (
|
|
b0 = -0.0000294
|
|
b1 = -0.00000057
|
|
b2 = 0.00000000463
|
|
c2 = 13.4
|
|
tref = 298.15
|
|
a2 = -0.00001678
|
|
a1 = 0.00175
|
|
s0 = 6.4
|
|
|
|
vObjReg = 0x00
|
|
tempAmbReg = 0x01
|
|
configReg = 0x02
|
|
manIdReg = 0xFE
|
|
manId = 0x5449
|
|
devIdReg = 0xFF
|
|
devId = 0x0067
|
|
|
|
reset = 0x8000
|
|
modeOn = 0x7000
|
|
drdyEn = 0x0100
|
|
|
|
configRegDefault = modeOn | drdyEn
|
|
)
|
|
|
|
type SampleRate struct {
|
|
enabler uint16
|
|
samples int
|
|
timeRequired float64
|
|
}
|
|
|
|
var (
|
|
SR1 = &SampleRate{0x0000, 1, 0.25} // 1 sample, 0.25 second between measurements.
|
|
SR2 = &SampleRate{0x0200, 2, 0.5} // 2 samples, 0.5 second between measurements.
|
|
SR4 = &SampleRate{0x0400, 4, 1} // 4 samples, 1 second between measurements.
|
|
SR8 = &SampleRate{0x0600, 8, 2} // 8 samples, 2 seconds between measurements.
|
|
SR16 = &SampleRate{0x0800, 16, 4} // 16 samples, 4 seconds between measurements.
|
|
)
|
|
|
|
// TMP006 represents a TMP006 thermopile sensor.
|
|
type TMP006 struct {
|
|
// Bus to communicate over.
|
|
Bus embd.I2CBus
|
|
// Addr of the sensor.
|
|
Addr byte
|
|
// SampleRate specifies the sampling rate for the sensor.
|
|
SampleRate *SampleRate
|
|
|
|
initialized bool
|
|
mu sync.RWMutex
|
|
|
|
rawDieTemps chan float64
|
|
objTemps chan float64
|
|
closing chan chan struct{}
|
|
}
|
|
|
|
// New creates a new TMP006 sensor.
|
|
func New(bus embd.I2CBus, addr byte) *TMP006 {
|
|
return &TMP006{
|
|
Bus: bus,
|
|
Addr: addr,
|
|
}
|
|
}
|
|
|
|
func (d *TMP006) validate() error {
|
|
if d.Bus == nil {
|
|
return errors.New("tmp006: bus is nil")
|
|
}
|
|
if d.Addr == 0x00 {
|
|
return fmt.Errorf("tmp006: %#x is not a valid address", d.Addr)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Close puts the device into low power mode.
|
|
func (d *TMP006) Close() error {
|
|
if err := d.setup(); err != nil {
|
|
return err
|
|
}
|
|
if d.closing != nil {
|
|
waitc := make(chan struct{})
|
|
d.closing <- waitc
|
|
<-waitc
|
|
}
|
|
glog.V(1).Infof("tmp006: resetting")
|
|
if err := d.Bus.WriteWordToReg(d.Addr, configReg, reset); err != nil {
|
|
return err
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Present checks if the device is present at the given address.
|
|
func (d *TMP006) Present() (bool, error) {
|
|
if err := d.validate(); err != nil {
|
|
return false, err
|
|
}
|
|
mid, err := d.Bus.ReadWordFromReg(d.Addr, manIdReg)
|
|
if err != nil {
|
|
return false, err
|
|
}
|
|
glog.V(1).Infof("tmp006: got manufacturer id %#04x", mid)
|
|
if mid != manId {
|
|
return false, fmt.Errorf("tmp006: not found at %#02x, manufacturer id mismatch", d.Addr)
|
|
}
|
|
did, err := d.Bus.ReadWordFromReg(d.Addr, devIdReg)
|
|
if err != nil {
|
|
return false, err
|
|
}
|
|
glog.V(1).Infof("tmp006: got device id %#04x", did)
|
|
if did != devId {
|
|
return false, fmt.Errorf("tmp006: not found at %#02x, device id mismatch", d.Addr)
|
|
}
|
|
|
|
return true, nil
|
|
}
|
|
|
|
func (d *TMP006) setup() error {
|
|
d.mu.RLock()
|
|
if d.initialized {
|
|
d.mu.RUnlock()
|
|
return nil
|
|
}
|
|
d.mu.RUnlock()
|
|
|
|
d.mu.Lock()
|
|
defer d.mu.Unlock()
|
|
|
|
if err := d.validate(); err != nil {
|
|
return err
|
|
}
|
|
if d.SampleRate == nil {
|
|
glog.V(1).Infof("tmp006: sample rate = nil, using SR16")
|
|
d.SampleRate = SR16
|
|
}
|
|
glog.V(1).Infof("tmp006: configuring with %#04x", configRegDefault|d.SampleRate.enabler)
|
|
if err := d.Bus.WriteWordToReg(d.Addr, configReg, configRegDefault|d.SampleRate.enabler); err != nil {
|
|
return err
|
|
}
|
|
|
|
d.initialized = true
|
|
|
|
return nil
|
|
}
|
|
|
|
func (d *TMP006) measureRawDieTemp() (float64, error) {
|
|
if err := d.setup(); err != nil {
|
|
return 0, err
|
|
}
|
|
raw, err := d.Bus.ReadWordFromReg(d.Addr, tempAmbReg)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
raw >>= 2
|
|
glog.V(2).Infof("tmp006: raw die temp %#04x", raw)
|
|
|
|
temp := float64(int16(raw)) * 0.03125
|
|
|
|
return temp, nil
|
|
}
|
|
|
|
func (d *TMP006) measureRawVoltage() (int16, error) {
|
|
if err := d.setup(); err != nil {
|
|
return 0, err
|
|
}
|
|
vlt, err := d.Bus.ReadWordFromReg(d.Addr, vObjReg)
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
volt := int16(vlt)
|
|
glog.V(2).Infof("tmp006: raw voltage %#04x", volt)
|
|
return volt, nil
|
|
}
|
|
|
|
func (d *TMP006) measureObjTemp() (float64, error) {
|
|
if err := d.setup(); err != nil {
|
|
return 0, err
|
|
}
|
|
tDie, err := d.measureRawDieTemp()
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
glog.V(2).Infof("tmp006: tdie = %.2f C", tDie)
|
|
tDie += 273.15 // Convert to K
|
|
vo, err := d.measureRawVoltage()
|
|
if err != nil {
|
|
return 0, err
|
|
}
|
|
vObj := float64(vo)
|
|
vObj *= 156.25 // 156.25 nV per LSB
|
|
vObj /= 1000 // nV -> uV
|
|
glog.V(2).Infof("tmp006: vObj = %.5f uV", vObj)
|
|
vObj /= 1000 // uV -> mV
|
|
vObj /= 1000 // mV -> V
|
|
|
|
tdie_tref := tDie - tref
|
|
s := 1 + a1*tdie_tref + a2*tdie_tref*tdie_tref
|
|
s *= s0
|
|
s /= 10000000
|
|
s /= 10000000
|
|
|
|
Vos := b0 + b1*tdie_tref + b2*tdie_tref*tdie_tref
|
|
fVobj := (vObj - Vos) + c2*(vObj-Vos)*(vObj-Vos)
|
|
|
|
temp := math.Sqrt(math.Sqrt(tDie*tDie*tDie*tDie + fVobj/s))
|
|
temp -= 273.15
|
|
|
|
return temp, nil
|
|
}
|
|
|
|
// RawDieTemp returns the current raw die temp reading.
|
|
func (d *TMP006) RawDieTemp() (float64, error) {
|
|
select {
|
|
case temp := <-d.rawDieTemps:
|
|
return temp, nil
|
|
default:
|
|
return d.measureRawDieTemp()
|
|
}
|
|
}
|
|
|
|
// RawDieTemps returns a channel to get future raw die temps from.
|
|
func (d *TMP006) RawDieTemps() <-chan float64 {
|
|
return d.rawDieTemps
|
|
}
|
|
|
|
// ObjTemp returns the current obj temp reading.
|
|
func (d *TMP006) ObjTemp() (float64, error) {
|
|
select {
|
|
case temp := <-d.objTemps:
|
|
return temp, nil
|
|
default:
|
|
return d.measureObjTemp()
|
|
}
|
|
}
|
|
|
|
// ObjTemps returns a channel to fetch obj temps from.
|
|
func (d *TMP006) ObjTemps() <-chan float64 {
|
|
return d.objTemps
|
|
}
|
|
|
|
// Start starts the data acquisition loop.
|
|
func (d *TMP006) Start() error {
|
|
if err := d.setup(); err != nil {
|
|
return err
|
|
}
|
|
|
|
d.rawDieTemps = make(chan float64)
|
|
d.objTemps = make(chan float64)
|
|
|
|
go func() {
|
|
var rawDieTemp, objTemp float64
|
|
var rdtAvlb, otAvlb bool
|
|
var err error
|
|
var timer <-chan time.Time
|
|
resetTimer := func() {
|
|
timer = time.After(time.Duration(d.SampleRate.timeRequired*1000) * time.Millisecond)
|
|
}
|
|
resetTimer()
|
|
|
|
for {
|
|
var rawDieTemps, objTemps chan float64
|
|
|
|
if rdtAvlb {
|
|
rawDieTemps = d.rawDieTemps
|
|
}
|
|
if otAvlb {
|
|
objTemps = d.objTemps
|
|
}
|
|
|
|
select {
|
|
case <-timer:
|
|
var rdt float64
|
|
if rdt, err = d.measureRawDieTemp(); err != nil {
|
|
glog.Errorf("tmp006: %v", err)
|
|
} else {
|
|
rawDieTemp = rdt
|
|
rdtAvlb = true
|
|
}
|
|
var ot float64
|
|
if ot, err = d.measureObjTemp(); err != nil {
|
|
glog.Errorf("tmp006: %v", err)
|
|
} else {
|
|
objTemp = ot
|
|
otAvlb = true
|
|
}
|
|
resetTimer()
|
|
case rawDieTemps <- rawDieTemp:
|
|
rdtAvlb = false
|
|
case objTemps <- objTemp:
|
|
otAvlb = false
|
|
case waitc := <-d.closing:
|
|
waitc <- struct{}{}
|
|
close(d.rawDieTemps)
|
|
close(d.objTemps)
|
|
return
|
|
}
|
|
}
|
|
}()
|
|
|
|
return nil
|
|
}
|