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embd
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simplify temp set and read functions

This commit is contained in:
Adam Bright 2016-09-26 04:01:22 +00:00
parent afc8c08cff
commit 606555ca7f
1 changed files with 7 additions and 41 deletions
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48
sensor/mcp9808/mcp9808.go
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@ -4,7 +4,6 @@
package mcp9808
import (
"math"
"sync"
"github.com/kidoman/embd"
@ -319,44 +318,11 @@ func (d *MCP9808) readTempC(reg byte) (float64, error) {
}
func convertWordToTempC(temp uint16) float64 {
wholeNum := float64(temp&0xFF0) / 16.0
fraction := float64(temp&0xF) * .0625
tempRead := wholeNum + fraction
// read sign bit
if temp>>12 == 1 {
tempRead *= -1
}
return tempRead
return float64(int16(temp<<3)>>3) / 16
}
func (d *MCP9808) setTemp(reg byte, newTemp float64) error {
d.cmu.Lock()
defer d.cmu.Unlock()
var signBit uint16
if newTemp < 0 {
newTemp *= -1
signBit = 0x1000
}
wholeNum, fraction := math.Modf(newTemp)
var roundedFrac uint16
switch {
case fraction < .125:
roundedFrac = 0
case fraction < .375:
roundedFrac = 1
case fraction < .625:
roundedFrac = 2
case fraction < .875:
roundedFrac = 3
default:
roundedFrac = 4
}
newTempWord := signBit + uint16(wholeNum)*16 + roundedFrac*4
return d.Bus.WriteWordToReg(address, reg, newTempWord)
return d.Bus.WriteWordToReg(address, reg, uint16((newTemp)*16)&0x1fff)
}
// AmbientTemp reads the current sensor value along with the flags denoting what boundaries the
@ -368,16 +334,16 @@ func (d *MCP9808) AmbientTemp() (*Temperature, error) {
}
tempResult := &Temperature{
AboveCritical: !(temp&(1<<15) == 0),
AboveUpper: !(temp&(1<<14) == 0),
BelowLower: !(temp&(1<<13) == 0)}
AboveCritical: temp&0x8000 == 0x8000,
AboveUpper: temp&0x4000 == 0x4000,
BelowLower: temp&0x2000 == 0x2000}
tempResult.CelsiusDeg = convertWordToTempC(temp)
return tempResult, nil
}
// CriticalTempUpper reads the current temperature set in the critical temperature register.
func (d *MCP9808) CriticalTempUpper() (float64, error) {
// CriticalTemp reads the current temperature set in the critical temperature register.
func (d *MCP9808) CriticalTemp() (float64, error) {
return d.readTempC(regCriticalTemp)
}