mirror of https://github.com/kidoman/embd
Merge 31f3386652
into d3d8c0c5c6
This commit is contained in:
commit
a4d939f70e
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@ -0,0 +1,119 @@
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package main
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import (
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||||
"bufio"
|
||||
"fmt"
|
||||
"os"
|
||||
|
||||
"github.com/kidoman/embd"
|
||||
_ "github.com/kidoman/embd/host/rpi"
|
||||
"github.com/kidoman/embd/sensor/mcp9808"
|
||||
)
|
||||
|
||||
func main() {
|
||||
bus := embd.NewI2CBus(1)
|
||||
defer embd.CloseI2C()
|
||||
|
||||
therm, _ := mcp9808.New(bus)
|
||||
// set sensor to low power mode when we're done
|
||||
defer therm.SetShutdownMode(true)
|
||||
|
||||
if id, err := therm.ManufacturerID(); err == nil {
|
||||
fmt.Printf("Manufacturer ID: 0x%x\n", id)
|
||||
}
|
||||
|
||||
if devID, rev, err := therm.DeviceID(); err == nil {
|
||||
fmt.Printf("Device ID: 0x%x rev. 0x%x\n", devID, rev)
|
||||
}
|
||||
|
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therm.SetShutdownMode(false)
|
||||
therm.SetCriticalTempLock(false)
|
||||
therm.SetWindowTempLock(false)
|
||||
therm.SetAlertMode(true)
|
||||
therm.SetInterruptClear(true)
|
||||
therm.SetAlertStatus(true)
|
||||
therm.SetAlertControl(true)
|
||||
therm.SetAlertSelect(false)
|
||||
therm.SetAlertPolarity(true)
|
||||
|
||||
// get faster results (130ms vs 250ms default)
|
||||
therm.SetTempResolution(mcp9808.EighthC)
|
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|
||||
config, _ := therm.Config()
|
||||
fmt.Printf("New Config: %b\n", config)
|
||||
|
||||
if err := therm.SetCriticalTemp(TempFToC(95)); err != nil {
|
||||
panic(err)
|
||||
}
|
||||
critTemp, err := therm.CriticalTemp()
|
||||
if err != nil {
|
||||
fmt.Printf("Error reading critical temp limit: %s\n", err.Error())
|
||||
}
|
||||
fmt.Printf("Critical Temp set to: %fC\n", critTemp)
|
||||
|
||||
if err := therm.SetWindowTempLower(TempFToC(60)); err != nil {
|
||||
panic(err)
|
||||
}
|
||||
lowerTemp, err := therm.WindowTempLower()
|
||||
if err != nil {
|
||||
fmt.Printf("Error reading lower temp limit: %s\n", err.Error())
|
||||
}
|
||||
fmt.Printf("Lower Temp Limit set to: %fC\n", lowerTemp)
|
||||
|
||||
if err := therm.SetWindowTempUpper(TempFToC(80)); err != nil {
|
||||
panic(err)
|
||||
}
|
||||
upperTemp, _ := therm.WindowTempUpper()
|
||||
fmt.Printf("Upper Temp Limit set to: %fC\n", upperTemp)
|
||||
|
||||
therm.SetCriticalTempLock(true)
|
||||
therm.SetWindowTempLock(true)
|
||||
|
||||
alert, err := embd.NewDigitalPin(23)
|
||||
if err != nil {
|
||||
panic(err)
|
||||
}
|
||||
defer alert.Close()
|
||||
|
||||
alert.SetDirection(embd.In)
|
||||
alert.ActiveLow(false)
|
||||
|
||||
err = alert.Watch(embd.EdgeRising, func(alert embd.DigitalPin) {
|
||||
fmt.Printf("Temperature is outside the specified window!\n")
|
||||
therm.SetInterruptClear(true)
|
||||
therm.Config()
|
||||
})
|
||||
if err != nil {
|
||||
panic(err)
|
||||
}
|
||||
|
||||
cancel := make(chan bool)
|
||||
go func() {
|
||||
reader := bufio.NewReader(os.Stdin)
|
||||
reader.ReadString('\n')
|
||||
cancel <- true
|
||||
}()
|
||||
|
||||
for {
|
||||
select {
|
||||
case <-cancel:
|
||||
return
|
||||
default:
|
||||
temp, err := therm.AmbientTemp()
|
||||
if err != nil {
|
||||
fmt.Printf("Error reading temp: %s\n", err.Error())
|
||||
} else {
|
||||
fmt.Printf("Current temp is: %fF (%fC), Window Alert: %v, Critical Alert: %v\n",
|
||||
TempCToF(temp.CelsiusDeg), temp.CelsiusDeg, temp.AboveUpper || temp.BelowLower, temp.AboveCritical)
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func TempCToF(tempC float64) float64 {
|
||||
return tempC*9/5 + 32
|
||||
}
|
||||
|
||||
func TempFToC(tempF float64) float64 {
|
||||
return (tempF - 32) * 5 / 9
|
||||
}
|
|
@ -0,0 +1,382 @@
|
|||
// Package mcp9808 is a driver for the MCP9808 temperature sensor
|
||||
// and all code is based off of the documentation found here:
|
||||
// http://ww1.microchip.com/downloads/en/DeviceDoc/25095A.pdf
|
||||
package mcp9808
|
||||
|
||||
import "github.com/kidoman/embd"
|
||||
|
||||
const (
|
||||
// default I2C address for device
|
||||
address = 0x18
|
||||
|
||||
// Register addresses.
|
||||
regConfig = iota // starts at 1, this is what we want
|
||||
regUpperTemp
|
||||
regLowerTemp
|
||||
regCriticalTemp
|
||||
regAmbientTemp
|
||||
regManufID
|
||||
regDeviceID
|
||||
regResolution
|
||||
)
|
||||
|
||||
const (
|
||||
configAlertMode uint16 = 1 << iota
|
||||
configAlertPolarity
|
||||
configAlertSelect
|
||||
configAlertControl
|
||||
configAlertStatus
|
||||
configInterruptClear
|
||||
configWindowTempLock
|
||||
configCriticalTempLock
|
||||
configShutDown
|
||||
)
|
||||
|
||||
// MCP9808 represents a MCP9808 temperature sensor.
|
||||
type MCP9808 struct {
|
||||
Bus embd.I2CBus
|
||||
config uint16
|
||||
}
|
||||
|
||||
// New returns a handle to a MCP9808 sensor.
|
||||
func New(bus embd.I2CBus) (*MCP9808, error) {
|
||||
d := &MCP9808{Bus: bus}
|
||||
|
||||
// initialize the configuration
|
||||
_, err := d.Config()
|
||||
return d, err
|
||||
}
|
||||
|
||||
// ManufacturerID reads the device manufacturer ID
|
||||
func (d *MCP9808) ManufacturerID() (uint16, error) {
|
||||
return d.Bus.ReadWordFromReg(address, regManufID)
|
||||
}
|
||||
|
||||
// DeviceID reads the device ID and revision
|
||||
func (d *MCP9808) DeviceID() (uint8, uint8, error) {
|
||||
devIDRev, err := d.Bus.ReadWordFromReg(address, regDeviceID)
|
||||
if err != nil {
|
||||
return 0, 0, err
|
||||
}
|
||||
|
||||
return uint8(devIDRev >> 8), uint8(devIDRev & 0xFF), nil
|
||||
}
|
||||
|
||||
// Config gets the config word from the device.
|
||||
func (d *MCP9808) Config() (uint16, error) {
|
||||
config, err := d.Bus.ReadWordFromReg(address, regConfig)
|
||||
if err != nil {
|
||||
return 0, err
|
||||
}
|
||||
d.config = config
|
||||
return d.config, nil
|
||||
}
|
||||
|
||||
// setConfig writes the sensor's config word to the device and returns the resulting config
|
||||
func (d *MCP9808) setConfig() error {
|
||||
return d.Bus.WriteWordToReg(address, regConfig, d.config)
|
||||
}
|
||||
|
||||
// flipConfig bit sets (1, set = true) or clears (0, set = false) a bit within the config word
|
||||
func (d *MCP9808) flipConfigBit(val uint16, set bool) error {
|
||||
if set {
|
||||
d.config |= val
|
||||
} else {
|
||||
d.config &= ^val
|
||||
}
|
||||
return d.setConfig()
|
||||
}
|
||||
|
||||
func (d *MCP9808) readConfigValue(val uint16) (bool, error) {
|
||||
config, err := d.Config()
|
||||
return !(config&(1<<val) == 0), err
|
||||
}
|
||||
|
||||
// Hysteresis applies for decreasing temperature only (hot to cold) or as temperature
|
||||
// drifts below the specified limit.
|
||||
type Hysteresis uint8
|
||||
|
||||
const (
|
||||
// Zero hysteresis represents 0 degrees Celsius of hysteresis compensation
|
||||
Zero Hysteresis = iota
|
||||
// Plus1pt5 hysteresis represents +1.5 degrees Celsius of hysteresis compensation
|
||||
Plus1pt5
|
||||
// Plus3pt0 hysteresis represents +3.0 degrees Celsius of hysteresis compensation
|
||||
Plus3pt0
|
||||
// Plus6pt0 hysteresis represents +6.0 degrees Celsius of hysteresis compensation
|
||||
Plus6pt0
|
||||
)
|
||||
|
||||
// TempHysteresis - TUPPER and TLOWER Limit Hysteresis bits
|
||||
// 00 = 0°C (power-up default)
|
||||
// 01 = +1.5°C
|
||||
// 10 = +3.0°C
|
||||
// 11 = +6.0°C
|
||||
// The hysteresis applies for decreasing temperature only (hot to cold) or as temperature
|
||||
// drifts below the specified limit.
|
||||
func (d *MCP9808) TempHysteresis() (Hysteresis, error) {
|
||||
_, err := d.Config()
|
||||
return Hysteresis(d.config >> 9), err
|
||||
}
|
||||
|
||||
// SetTempHysteresis - TUPPER and TLOWER Limit Hysteresis bits
|
||||
// 00 = 0°C (power-up default)
|
||||
// 01 = +1.5°C
|
||||
// 10 = +3.0°C
|
||||
// 11 = +6.0°C
|
||||
// The hysteresis applies for decreasing temperature only (hot to cold) or as temperature
|
||||
// drifts below the specified limit.
|
||||
// This bit can not be altered when either of the Lock bits are set (bit 6 and bit 7).
|
||||
// Thi s bit can be programmed in Shutdown mode.
|
||||
func (d *MCP9808) SetTempHysteresis(val Hysteresis) error {
|
||||
d.config = d.config - d.config&^(d.config>>9) + uint16(val)<<9
|
||||
return d.setConfig()
|
||||
}
|
||||
|
||||
// ShutdownMode bit
|
||||
// 0 (false) = Continuous conversion (power-up default)
|
||||
// 1 (true) = Shutdown (Low-Power mode)
|
||||
// In shutdown, all power-consuming activities are disabled, though all registers can be written to or read.
|
||||
func (d *MCP9808) ShutdownMode() (bool, error) {
|
||||
return d.readConfigValue(configShutDown)
|
||||
}
|
||||
|
||||
// SetShutdownMode bit
|
||||
// 0 (false) = Continuous conversion (power-up default)
|
||||
// 1 (true) = Shutdown (Low-Power mode)
|
||||
// In shutdown, all power-consuming activities are disabled, though all registers can be written to or read.
|
||||
// This bit cannot be set to ‘1’ when either of the Lock bits is set (bit 6 and bit 7). However, it can be
|
||||
// cleared to ‘0’ for continuous conversion while locked
|
||||
func (d *MCP9808) SetShutdownMode(set bool) error {
|
||||
return d.flipConfigBit(configShutDown, set)
|
||||
}
|
||||
|
||||
// CriticalTempLock - TCRIT Lock bit
|
||||
// 0 (false) = Unlocked. TCRIT register can be written (power-up default)
|
||||
// 1 (true) = Locked. TCRIT register can not be written
|
||||
// When enabled, this bit remains set to ‘1’ or locked until cleared by an internal Reset
|
||||
func (d *MCP9808) CriticalTempLock() (bool, error) {
|
||||
return d.readConfigValue(configCriticalTempLock)
|
||||
}
|
||||
|
||||
// SetCriticalTempLock - TCRIT Lock bit
|
||||
// 0 (false) = Unlocked. TCRIT register can be written (power-up default)
|
||||
// 1 (true) = Locked. TCRIT register can not be written
|
||||
// When enabled, this bit remains set to ‘1’ or locked until cleared by an internal Reset
|
||||
// This bit can be programmed in Shutdown mode.
|
||||
func (d *MCP9808) SetCriticalTempLock(locked bool) error {
|
||||
return d.flipConfigBit(configCriticalTempLock, locked)
|
||||
}
|
||||
|
||||
// WindowTempLock - TUPPER and TLOWER Window Lock bit
|
||||
// 0 (false) = Unlocked; TUPPER and TLOWER registers can be written (power-up default)
|
||||
// 1 (true) = Locked; TUPPER and TLOWER registers can not be written
|
||||
// When enabled, this bit remains set to ‘1’ or locked until cleared by a Power-on Reset
|
||||
func (d *MCP9808) WindowTempLock() (bool, error) {
|
||||
return d.readConfigValue(configWindowTempLock)
|
||||
}
|
||||
|
||||
// SetWindowTempLock - TUPPER and TLOWER Window Lock bit
|
||||
// 0 (false) = Unlocked; TUPPER and TLOWER registers can be written (power-up default)
|
||||
// 1 (true) = Locked; TUPPER and TLOWER registers can not be written
|
||||
// When enabled, this bit remains set to ‘1’ or locked until cleared by a Power-on Reset
|
||||
// This bit can be programmed in Shutdown mode.
|
||||
func (d *MCP9808) SetWindowTempLock(locked bool) error {
|
||||
return d.flipConfigBit(configWindowTempLock, locked)
|
||||
}
|
||||
|
||||
// InterruptClear - Interrupt Clear bit
|
||||
// 0 (false) = No effect (power-up default)
|
||||
// 1 (true) = Clear interrupt output; when read, this bit returns to ‘0’
|
||||
func (d *MCP9808) InterruptClear() (bool, error) {
|
||||
return d.readConfigValue(configInterruptClear)
|
||||
}
|
||||
|
||||
// SetInterruptClear - Interrupt Clear bit
|
||||
// 0 (false) = No effect (power-up default)
|
||||
// 1 (true) = Clear interrupt output; when read, this bit returns to ‘0’
|
||||
// This bit can not be set to ‘1’ in Shutdown mode, but it can be cleared after the device enters Shutdown
|
||||
// mode.
|
||||
func (d *MCP9808) SetInterruptClear(set bool) error {
|
||||
return d.flipConfigBit(configInterruptClear, set)
|
||||
}
|
||||
|
||||
// AlertStatus Alert Output Status bit
|
||||
// 0 (false) = Alert output is not asserted by the device (power-up default)
|
||||
// 1 (true) = Alert output is asserted as a comparator/Interrupt or critical temperature output
|
||||
func (d *MCP9808) AlertStatus() (bool, error) {
|
||||
return d.readConfigValue(configAlertStatus)
|
||||
}
|
||||
|
||||
// SetAlertStatus Alert Output Status bit
|
||||
// 0 (false) = Alert output is not asserted by the device (power-up default)
|
||||
// 1 (true) = Alert output is asserted as a comparator/Interrupt or critical temperature output
|
||||
// This bit can not be set to ‘1’ or cleared to ‘0’ in Shutdown mode. However, if the Alert output is configured
|
||||
// as Interrupt mode, and if the host controller clears to ‘0’, the interrupt, using bit 5 while the device
|
||||
// is in Shutdown mode, then this bit will also be cleared ‘0’.
|
||||
func (d *MCP9808) SetAlertStatus(set bool) error {
|
||||
return d.flipConfigBit(configAlertStatus, set)
|
||||
}
|
||||
|
||||
// AlertControl - Alert Output Control bit
|
||||
// 0 (false) = Disabled (power-up default)
|
||||
// 1 (true) = Enabled
|
||||
func (d *MCP9808) AlertControl() (bool, error) {
|
||||
return d.readConfigValue(configAlertControl)
|
||||
}
|
||||
|
||||
// SetAlertControl - Alert Output Control bit
|
||||
// 0 (false) = Disabled (power-up default)
|
||||
// 1 (true) = Enabled
|
||||
// This bit can not be altered when either of the Lock bits are set (bit 6 and bit 7).
|
||||
// This bit can be programmed in Shutdown mode, but the Alert output will not assert or deassert.
|
||||
func (d *MCP9808) SetAlertControl(set bool) error {
|
||||
return d.flipConfigBit(configAlertControl, set)
|
||||
}
|
||||
|
||||
// AlertSelect - Alert Output Select bit
|
||||
// 0 (false) = Alert output for TUPPER, TLOWER and TCRIT (power-up default)
|
||||
// 1 (true) = TA > TCRIT only (TUPPER and TLOWER temperature boundaries are disabled)
|
||||
func (d *MCP9808) AlertSelect() (bool, error) {
|
||||
return d.readConfigValue(configAlertSelect)
|
||||
}
|
||||
|
||||
// SetAlertSelect - Alert Output Select bit
|
||||
// 0 (false) = Alert output for TUPPER, TLOWER and TCRIT (power-up default)
|
||||
// 1 (true) = TA > TCRIT only (TUPPER and TLOWER temperature boundaries are disabled)
|
||||
// When the Alarm Window Lock bit is set, this bit cannot be altered until unlocked (bit 6).
|
||||
// This bit can be programmed in Shutdown mode, but the Alert output will not assert or deassert.
|
||||
func (d *MCP9808) SetAlertSelect(set bool) error {
|
||||
return d.flipConfigBit(configAlertSelect, set)
|
||||
}
|
||||
|
||||
// AlertPolarity - Alert Output Polarity bit
|
||||
// 0 (false) = Active-low (power-up default; pull-up resistor required)
|
||||
// 1 (true) = Active-high
|
||||
func (d *MCP9808) AlertPolarity() (bool, error) {
|
||||
return d.readConfigValue(configAlertPolarity)
|
||||
}
|
||||
|
||||
// SetAlertPolarity - Alert Output Polarity bit
|
||||
// 0 (false) = Active-low (power-up default; pull-up resistor required)
|
||||
// 1 (true) = Active-high
|
||||
// This bit cannot be altered when either of the Lock bits are set (bit 6 and bit 7).
|
||||
// This bit can be programmed in Shutdown mode, but the Alert output will not assert or deassert.
|
||||
func (d *MCP9808) SetAlertPolarity(set bool) error {
|
||||
return d.flipConfigBit(configAlertPolarity, set)
|
||||
}
|
||||
|
||||
// AlertMode - Alert Output Mode bit
|
||||
// 0 (false) = Comparator output (power-up default)
|
||||
// 1 (true) = Interrupt output
|
||||
func (d *MCP9808) AlertMode() (bool, error) {
|
||||
return d.readConfigValue(configAlertMode)
|
||||
}
|
||||
|
||||
// SetAlertMode - Alert Output Mode bit
|
||||
// 0 (false) = Comparator output (power-up default)
|
||||
// 1 (true) = Interrupt output
|
||||
// This bit cannot be altered when either of the Lock bits are set (bit 6 and bit 7).
|
||||
// This bit can be programmed in Shutdown mode, but the Alert output will not assert or deassert.
|
||||
func (d *MCP9808) SetAlertMode(set bool) error {
|
||||
return d.flipConfigBit(configAlertMode, set)
|
||||
}
|
||||
|
||||
// Temperature contains the ambient temperature along with alert values.
|
||||
type Temperature struct {
|
||||
CelsiusDeg float64
|
||||
AboveCritical, AboveUpper, BelowLower bool
|
||||
}
|
||||
|
||||
// readTempC reads from the reg temperature register and returns the current temperature value in celsius
|
||||
func (d *MCP9808) readTempC(reg byte) (float64, error) {
|
||||
temp, err := d.Bus.ReadWordFromReg(address, reg)
|
||||
if err != nil {
|
||||
return 0, err
|
||||
}
|
||||
|
||||
return convertWordToTempC(temp), nil
|
||||
}
|
||||
|
||||
func convertWordToTempC(temp uint16) float64 {
|
||||
return float64(int16(temp<<3)>>3) / 16
|
||||
}
|
||||
|
||||
func (d *MCP9808) setTemp(reg byte, newTemp float64) error {
|
||||
return d.Bus.WriteWordToReg(address, reg, uint16(newTemp*16+2)&0x1ffc)
|
||||
}
|
||||
|
||||
// AmbientTemp reads the current sensor value along with the flags denoting what boundaries the
|
||||
// current temperature exceeds.
|
||||
func (d *MCP9808) AmbientTemp() (*Temperature, error) {
|
||||
temp, err := d.Bus.ReadWordFromReg(address, regAmbientTemp)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
tempResult := &Temperature{
|
||||
AboveCritical: temp&0x8000 == 0x8000,
|
||||
AboveUpper: temp&0x4000 == 0x4000,
|
||||
BelowLower: temp&0x2000 == 0x2000}
|
||||
tempResult.CelsiusDeg = convertWordToTempC(temp)
|
||||
|
||||
return tempResult, nil
|
||||
}
|
||||
|
||||
// CriticalTemp reads the current temperature set in the critical temperature register.
|
||||
func (d *MCP9808) CriticalTemp() (float64, error) {
|
||||
return d.readTempC(regCriticalTemp)
|
||||
}
|
||||
|
||||
// SetCriticalTemp when the temperature goes above the set value the alert will be
|
||||
// triggered if enabled. This has no effect if CriticalTempLock is set.
|
||||
func (d *MCP9808) SetCriticalTemp(newTemp float64) error {
|
||||
return d.setTemp(regCriticalTemp, newTemp)
|
||||
}
|
||||
|
||||
// WindowTempUpper reads the current temperature set in the upper window temperature register.
|
||||
func (d *MCP9808) WindowTempUpper() (float64, error) {
|
||||
return d.readTempC(regUpperTemp)
|
||||
}
|
||||
|
||||
// SetWindowTempUpper when the temperature goes above the set value the alert will be
|
||||
// triggered if enabled. This has no effect if WindowTempLock is set.
|
||||
func (d *MCP9808) SetWindowTempUpper(newTemp float64) error {
|
||||
return d.setTemp(regUpperTemp, newTemp)
|
||||
}
|
||||
|
||||
// WindowTempLower reads the current temperature set in the lower window temperature register.
|
||||
func (d *MCP9808) WindowTempLower() (float64, error) {
|
||||
return d.readTempC(regLowerTemp)
|
||||
}
|
||||
|
||||
// SetWindowTempLower when the temperature goes below the set value the alert will be
|
||||
// triggered if enabled. This has no effect if WindowTempLock is set.
|
||||
func (d *MCP9808) SetWindowTempLower(newTemp float64) error {
|
||||
return d.setTemp(regLowerTemp, newTemp)
|
||||
}
|
||||
|
||||
// TempResolution reads the current temperature accuracy from the sensor (affects temperature read speed)
|
||||
// 0 - +/- .5 degrees C (~30ms)
|
||||
// 1 - +/- .25 degrees C (~65ms)
|
||||
// 2 - +/- .125 degrees C (~130ms)
|
||||
// 3 (default) - +/- .0625 degrees C (~250ms)
|
||||
type TempResolution uint8
|
||||
|
||||
const (
|
||||
HalfC TempResolution = iota
|
||||
QuarterC
|
||||
EighthC
|
||||
SixteenthC
|
||||
)
|
||||
|
||||
// TempResolution reads the temperature resolution from the sensor.
|
||||
func (d *MCP9808) TempResolution() (TempResolution, error) {
|
||||
res, err := d.Bus.ReadByteFromReg(address, regResolution)
|
||||
return TempResolution(res), err
|
||||
}
|
||||
|
||||
// SetTempResolution writes a new temperature resolution to the sensor
|
||||
func (d *MCP9808) SetTempResolution(res TempResolution) error {
|
||||
return d.Bus.WriteByteToReg(address, regResolution, byte(res))
|
||||
}
|
Loading…
Reference in New Issue