File content as of revision 5:6ca3e7ffc553:

#ifdef  INC_BARO

#include "mbed.h"
#include "baro.h"
#include "BufferedSerial.h"

//BufferedSerial  pc          (PA_2, PA_3, 512, 4, NULL);    //  Pins 16, 17    tx, rx to pc via usb lead
//I2C i2c                     (PB_7, PB_6);   //  Pins 58, 59 For 24LC64 eeprom
extern  BufferedSerial  pc;
extern  I2C i2c;
const int ACK     = 1;
const int NAK     = 0;
const int NOM_PASCALS   = 100000;
const int HYSTERESIS_PASCALS = 50;

MPL3115A2::MPL3115A2    ()  {   //  Constructor
        good = true;
//        mode = 0x39;  //  continuous convert
        mode = 0x38;    //  one shot
        Temp = Pres = Alti = Adju = 0.0;
        if  (!RegRd (0x0c, 1, dest))
            good = false;
        else if (dest[0] != 196)
            good = false;
}

bool    MPL3115A2::busy_check  ()  {
    char    c;
    RegRd   (0x26, 1, &c);
    c &= 2;
    if  (c == 0)
        return  false;  //  free, i.e. not busy
    return  true;       //  busy, conversion in progress
}

void    MPL3115A2::reset_zero_inHg  ()  {
    double tmp;
    Adju = 0.0;
    tmp = inHg_vacuum (); //  sets Adju
    Adju = tmp;
}
double  MPL3115A2::Temperature ()  {    return  Temp;   }
double  MPL3115A2::Pressure    ()  {    return  Pres;   }
double  MPL3115A2::Altitude    ()  {    return  Alti;   }
double  MPL3115A2::inHg_vacuum ()  {
    double  inHg = 0.0 - Pres;   //  one atmospheres worth of Pascals. Note 1 bar is not the same, 1 bar = 100000 Pa
    inHg *= 0.000295299833;
    return  inHg - Adju;
}
void    MPL3115A2::mode_alti   ()  {
//    mode = 0xb9;
    mode = 0xb8;
}
void    MPL3115A2::mode_pres   ()  {
//    mode = 0x39;
    mode = 0x38;
}
/*********************************************************\
* IIC Write Register
\*********************************************************/
bool MPL3115A2::RegWr  (int reg, char val)
{
    bool    rv = true;
    i2c.start   ();
    if  (i2c.write   (0xc0)     != ACK) rv = false;  //  Returns '0' - NAK was received '1' - ACK was received, '2' - timeout
    if  (i2c.write   (reg)      != ACK) rv = false;
    if  (i2c.write   (val)      != ACK) rv = false;
    i2c.stop    ();
    return  rv;
}

/*********************************************************\
* IIC Read One Or More Registers into array
\*********************************************************/
bool MPL3115A2::RegRd  (int reg1, int len, char *array)
{
    int acknak;
    bool    rv = true;
    i2c.start   ();
    if  (i2c.write   (0xc0) != ACK)     rv = false;  //  Returns '0' - NAK was received '1' - ACK was received, '2' - timeout
    if  (i2c.write   (reg1) != ACK)     rv = false;
    i2c.start   ();             // Send Repeat Start
    if  (i2c.write   (0xc1) != ACK)     rv = false;
    acknak = ACK;
    while (len > 0) {                                 // Read Register Values
        len--;
        if  (len == 0)    acknak = NAK;
        *array++ = i2c.read    (acknak);
    }
    i2c.stop    ();
    return  rv;
}

bool    MPL3115A2::Update    ()   {   //  Returns true on apparent success
    bool    rv = true;
    int32_t ta;
    if  (busy_check())  {   //  "User shall read the value of the OST bit before writing to this bit again." - done here.
        pc.printf   ("Call to Barometer Update while busy error\r\n");
        return  false;  //  Can not initiate new conversion, will not update Temp, Pres, Alti
    }
    Pres = Alti = -1.0; //  Gives added clue if call to Update fails
    if  (!RegRd (1, 5, dest))       rv = false;    //  Read 3 pressure + 2 temperature registers, then kick-start new conversion
    if  (!RegWr (0x26, mode | 2))   rv = false;    //  bit 1 is OST one shot mode, bits 3-5 are 128x oversampling. This starts new conversion
    if  (!rv)
        return  false;  //  register read or write failed, Pres and Alti = -1.0 also
    Temp = ((double) ((dest[3] << 4) | (dest[4] >> 4))) / 16.0; //  Temperature
    if  (mode & 0x80)  {    //  Altimeter mode
        ta = (dest[0] << 24) | (dest[1] << 16) | ((dest[2] & 0xf0) << 8);   //  preserve sign bit
        ta /= (1 << 12);
        Alti = ((double) ta) / 16.0;
        Pres = 0.0;
    }
    else    {   //  Pressure mode
        Pres = ((double) ((dest[0] << 12) | (dest[1] << 4) | (dest[2] >> 4))) / 4.0;
        Alti = 0.0;
    }
    return  true;
}


/*
int main()
{
    double  Pres, Alt, inHg, Heat;
    i2c.frequency(400000);      //  Speed 400000 max.
    class   MPL3115A2   baro    ;
    int q;      //  Note address bits 3-1 to match addr pins on 24LC16 memory device
    for (int i = 0; i < 255; i += 2)    {   //  Search for devices at all possible i2c addresses
        i2c.start();
        wait_ms (1);
        q = i2c.write(i);   //  may return error code 2 when no start issued
        switch  (q) {
            case    ACK:
                pc.printf   ("I2C device found at 0x%x\r\n", i);
            case    NAK:      //  Device not seen at this address
                break;
            case    2:      //  write reports timeout
                pc.printf   ("I2C Timeout at addr %2x\r\n", i);
                break;
            default:
                pc.printf   ("Unknown error %d in check_24LC64\r\n", q);
                break;
        }
    }
    i2c.stop();
    baro.mode_pres  ();
    pc.printf   ("baro good flag %s\r\n", baro.good ? "true":"false");
    bool    rv;
    q = -3;
    while(1) {
        q++;
        if  (q == 0)    baro.reset_zero_inHg();
        myled = 1; // LED is ON
        wait(0.3); // 200 ms
//        pc.printf   ("busy_check %s\r\n", baro.busy_check() ? "true":"false");
        myled = 0; // LED is OFF
        wait(0.8); // 1 sec
//        pc.printf   ("busy_check %s\r\n", baro.busy_check() ? "true":"false");
        rv  = baro.Update ();
        Pres = baro.Pressure();
        Alt = baro.Altitude();
        inHg = baro.inHg_vacuum();
        Heat = baro.Temperature();
const int NOM_PASCALS   = 100000;
const int HYSTERESIS_PASCALS = 50;
        if  (Pres > (NOM_PASCALS + HYSTERESIS_PASCALS))
            pump = 1;
        if  (Pres < (NOM_PASCALS - HYSTERESIS_PASCALS))
            pump = 0;
//        pc.printf   ("Pres\t%.2f Pa\tAlt\t%.1f m\t%+000.1f inHg\tTemp\t%.1f C, %s\r\n", baro.Pressure(), baro.Altitude(), baro.inHg_vacuum (), baro.Temperature(), rv ? "true":"false");
        pc.printf   ("Pres\t%.2f Pa\tAlt\t%.1f m\t%+000.1f inHg\tTemp\t%.1f C, %s\r\n", Pres, Alt, inHg, Heat, rv ? "true":"false");
//        rv  = baro.Update ();
    }
}
*/
#endif