Ivan Kravets / OneWire

OneWire Library lets you access 1-wire devices made by Maxim/Dallas, such as temperature sensors

Dependents:   OneWireTest mbed_blinky Affich_Lum_Moist Projetv0 ... more 

#include "mbed.h"
#include "OneWire.h"

OneWire owBus(p21);

int main()
{
    char _id[16];
    DeviceAddresses* devAddresses = owBus.getFoundDevAddresses();
    uint8_t foundNum = owBus.getFoundDevNum();
    printf("OneWire: found %d devices\r\n", foundNum);

    while(1) {
        OneWireDeviceTemperature::startConversationForAll(&owBus, OWTEMP_11_BIT);
        for (uint8_t i = 0; i < foundNum; i++) {
            OneWireDevice* owDevice = OneWireDeviceFactory::init(&owBus, (*devAddresses)[i]);
            
            if (owDevice->getFamily() != ONEWIRE_DS18B20_FAMILY)    // currently only DS18B20 supports
                continue;

            owDevice->generateId(_id);
            printf("OneWire: device #%s = %.4f*C\r\n", _id, (float) owDevice->sendGetCommand(GET_TEMPERATURE));
            delete owDevice;            
        }
        
        wait(5);
    }
 }

OneWire.h

Committer:
ivank
Date:
2012-11-12
Revision:
0:b9cd1d4dcc1f
Child:
2:07da4deb7135

File content as of revision 0:b9cd1d4dcc1f:

#ifndef ONEWIRE_H
#define ONEWIRE_H

#include "mbed.h"

#define FALSE 0
#define TRUE 1

#define ONEWIRE_DS18B20_FAMILY 0x28

enum OneWireDeviceCmd {
    SET_TEMPERATURE_RESOLUTION = 0,
    GET_TEMPERATURE
};

typedef uint8_t DeviceAddress[8];
typedef DeviceAddress*  DeviceAddresses;

class OneWire {
public:
    OneWire(PinName pin);

    uint8_t reset(void);
    uint8_t readByte(void);
    void writeByte(uint8_t val);
    void select(uint8_t* devAddr);
    void resetSearch(void);

    uint8_t search(uint8_t* devAddr);
    void sendGlobalCommand(uint8_t);
    DeviceAddresses* getFoundDevAddresses();
    uint8_t getFoundDevNum();

private:
    DigitalInOut DIO;
    static const uint8_t dscrc_table[];

    DeviceAddresses* foundDevAdresses;
    uint8_t foundDevNum;

    uint8_t lastDiscrep;
    uint8_t doneFlag;
    uint8_t dowcrc;

    uint8_t readBit(void);
    void writeBit(uint8_t bitval);

    void skip();
    uint8_t calcCRC(uint8_t x);
    void findDevAddresses(void);
};

class OneWireDevice {
public:
    OneWireDevice(OneWire* ow, DeviceAddress devAddr);
    //~OneWireDevice();
    void generateId(char* id);
    uint8_t getFamily();

    virtual void sendSetCommand(OneWireDeviceCmd cmd, uint8_t data) {};
    virtual float sendGetCommand(OneWireDeviceCmd cmd) {
        return 0;
    };

protected:
    OneWire* owBus;
    DeviceAddress address;
};

class OneWireDeviceTemperature : public OneWireDevice {
public:
    OneWireDeviceTemperature(OneWire* ow, DeviceAddress address) : OneWireDevice(ow, address) {};
    //static setResolutionForAll
    static void startConversationForAll(OneWire* owBus, uint8_t resolution);
};


class OneWireDeviceFactory {
public:
    static OneWireDevice* init(OneWire* owBus, DeviceAddress address);
};

#include "devices/ds18b20.h"
#endif