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Add support for DS2438 temperature sensors #15

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Add support for DS2438 temperature sensors #15

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55 changes: 43 additions & 12 deletions emonLibCM.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -50,6 +50,7 @@
// most of the code in the pulse ISR removed, replaced by countPulses( ) called from main loop.
// Version 2.2.1 5/12/2012 Repackaged 30/10/2021 release: Debugging statements accidentally left in pulse ISR removed.
// Version 2.2.2 15/9/2022 If temperature sensor pin had not been set but relied on default, no power was applied for initial search.
// Version 2.3 6/05/2023 Add support for DS2438 sensors

// #include "WProgram.h" un-comment for use on older versions of Arduino IDE

Expand Down Expand Up @@ -259,7 +260,7 @@ double x[max_no_of_channels], y[max_no_of_channels]; // coefficients for real po
// Temperature measurement
//
// Hardware Configuration
byte W1Pin = 5; // 1-Wire pin for temperature = 5 for emonTx V3, 4 for emonTx V2 & emonTx Shield
byte W1Pin = W1_PIN; // 1-Wire pin for temperature = 5 for emonTx V3, 4 for emonTx V2 & emonTx Shield
char DS18B20_PWR = -1; // Power pin for DS18B20 temperature sensors. Default -1 - power off

// Global variables used only inside the library
Expand Down Expand Up @@ -1229,6 +1230,8 @@ void EmonLibCM_TemperatureEnable(bool _enable)
return; // & quit.
}

Serial.println(W1Pin);
//oneWire.begin(W1Pin); // In case W1Pin has changed.

if (temperatureEnabled = _enable)
{
Expand All @@ -1251,14 +1254,14 @@ void EmonLibCM_TemperatureEnable(bool _enable)
oneWire.reset_search();
numSensors = 0;
while (oneWire.search(deviceAddress))
if (deviceAddress[0] == DS18B20SIG)
if (deviceAddress[0] == DS18B20SIG || deviceAddress[0] == DS2438SIG )
numSensors++;
if (keepAddresses && temperatureSensors[0][0] != 0x00)
{
numSensors = temperatureMaxCount;
for (numSensors = temperatureMaxCount; numSensors > 0; numSensors--)
{
if (temperatureSensors[numSensors-1][0] == DS18B20SIG) // signature of a DS18B20, so a pre-existing sensor
if (temperatureSensors[numSensors - 1][0] == DS18B20SIG || temperatureSensors[numSensors - 1][0] == DS2438SIG ) // signature of a DS18B20/DS2438, so a pre-existing sensor
break;
}
}
Expand All @@ -1270,7 +1273,7 @@ void EmonLibCM_TemperatureEnable(bool _enable)

byte j=0; // search for one wire devices and copy to device address array.

if (temperatureSensors[0][0] != DS18B20SIG) // not a signature of a DS18B20, so not a pre-existing array - search for sensors
if (temperatureSensors[0][0] != DS18B20SIG || temperatureSensors[0][0] != DS2438SIG ) // not a signature of a DS18B20, so not a pre-existing array - search for sensors
while ((j < numSensors) && (oneWire.search(temperatureSensors[j])))
j++;
oneWire.reset(); // write resolution to scratchpad
Expand Down Expand Up @@ -1362,6 +1365,8 @@ void convertTemperatures(void)

void retrieveTemperatures(void)
{
bool DS2438 = 0;

if (temperatureEnabled)
{
for (byte j=0; j < numSensors; j++)
Expand All @@ -1378,23 +1383,49 @@ void retrieveTemperatures(void)
else
{
oneWire.write(MATCH_ROM);
for(int i=0; i<8; i++)
for (int i = 0; i < 8; i++)
oneWire.write(temperatureSensors[j][i]);

if (temperatureSensors[j][0] == DS2438SIG) {
//DS2438 needs a RECALL_MEMORY CMD first
DS2438 = 1;
oneWire.write(0xB8); //Recall Memory
oneWire.write(0x00); //Page0
oneWire.reset() ;
oneWire.write(MATCH_ROM);
for (int i = 0; i < 8; i++)
oneWire.write(temperatureSensors[j][i]);
oneWire.write(READ_SCRATCHPAD);
for(int i=0; i<9; i++)
oneWire.write(0x00); //Page0 of scratchpad
} else {
DS2438 = 0 ;
oneWire.write(READ_SCRATCHPAD);
}

//Read the scratchpad 8 bytes + CRC into Buf
for (int i = 0; i < 9; i++)
buf[i] = oneWire.read();
}

if(oneWire.crc8(buf,8)==buf[8])

}

if ( oneWire.crc8(buf, 8) == buf[8])
{
result = (buf[1]<<8)|buf[0];
result = (buf[1] << 8) | buf[0];
if (DS2438) {
//DS2438 temp calculation x100
result = 100* (double)(((((int16_t)buf[2]) << 8) | (buf[1] & 0x0ff)) >> 3) * 0.03125 ;
} else {
// result is temperature x16, multiply by 6.25 to convert to temperature x100
result = (result*6)+(result>>2);
}
else result = BAD_TEMPERATURE;
if (buf[4] == 0)
} else {
result = BAD_TEMPERATURE;
if (buf[6] == 0x0C && result == 8500) // not genuine 85 °C
Serial.println("OneWire CRC failure.");
}
if (buf[4] == 0 && !DS2438 )
result = BAD_TEMPERATURE;
if (buf[6] == 0x0C && result == 8500 && !DS2438) // not genuine 85 °C
result = BAD_TEMPERATURE;
if (result != BAD_TEMPERATURE && (result < -5500 || result > 12500))
result = OUTOFRANGE_TEMPERATURE;
Expand Down
12 changes: 12 additions & 0 deletions emonLibCM.h
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Original file line number Diff line number Diff line change
Expand Up @@ -27,8 +27,18 @@
// Version 2.2.0 14/9/2021 Optional parameter 'edge' added to setPulseMinPeriod().
// Version 2.2.1 5/12/2021 Repackaged - no change.
// Version 2.2.2 15/9/2022 No change.
// Version 2.3 6/05/2023 Add support for DS2438 sensors

//If using with emonTx, ensure your define EMONTX below or the oneWire bus will be on the wrong pin.
// Defaulting to pin 4 seems sensible as this will stop 1W working on a EMONTX but will cause causing spurious shutdowns on an EMONPI.

#undef EMONTX

#ifdef EMONTX
#define W1_PIN 5 //1W pin on a EMONTX, Shutdown pin on EMONPI
#else
#define W1_PIN 4 //1W pin on a EMONPI
#endif

#ifndef EmonLibCM_h
#define EmonLibCM_h
Expand All @@ -51,7 +61,9 @@
#include <util/crc16.h>
#include <OneWire.h>


#define DS18B20SIG 0x28
#define DS2438SIG 0x26
#define SKIP_ROM 0xCC
#define MATCH_ROM 0x55
#define CONVERT_TEMPERATURE 0x44
Expand Down