File content as of revision 6:6aa9d16e27bc:

/* Run Honeywell Dust Sensor in continous Sampling Mode on a mDot
   Version 1.1
   Steve Mylroie Roitronic August 1st 2017
   @C Copyright Global Quality Corp
*/

#include "mbed.h"
#include "stdlib.h"

#define VERSION  "1.3"

#define TRACE_MODE

//Turn on trace logging to the PC USB port
#ifdef TRACE_MODE
//Log level need to be set one level higher than the high level to be output
#define LOG_LEVEL 2
#define DEBUG
#endif


const uint8_t* measureCommand = "68014057";
const uint8_t* stopCommand    = "68012077";

//Sensor command response codes
#define OK   0xA5A5
#define BAD  0x9696

//Auto Mode measurement response lenght
#define MESSAGE_LEN 32

//sensor measurement cycle in millseconds
#define MEASURE_DELAY 1500 

Serial pc(USBTX, USBRX, 115200);

//Use USB debug pott for the debug stream
#ifdef DEBUG
uint32_t debugLevel  = LOG_LEVEL;
#else
uint32_t debugLevel = 0;
#endif

void logInfo(char* text) {
     if ( debugLevel > 0 ) {
          pc.printf("\n%s\n", text );
     }
     return;
 }
 
void logTrace(uint8_t data) {
     if (debugLevel > 2 ){ pc.putc( data );
      }
      return;
  } 

//Board specfic serial port pin definitions

#ifdef TARGET_Freescale  //Freedom Board

#define SENSOR_XMT D1
#define SENSOR_RCV D0

#endif

#ifdef TARGET_MTS_MDOT_F411RE  //Multi Tech mDot

#define SENSOR_XMT PA_2
#define SENSOR_RCV PA_3

#endif

//Use a boards second UART   to communicate witb the Honneywell sensor
//Default UART setting are 8,N,1
Serial sensor( SENSOR_XMT, SENSOR_RCV, 9600);

//synchrnous serial read and writes
//Mbed 5 Serial class only supports single character read and writes or
// async buffer reads abd wrutes
void readBuffer(uint8_t* buffer, uint16_t count)
{
    logInfo( "Receiving Data from sensor\n");
    uint8_t* pointer = buffer;
    uint16_t counter = count;
    while(1)
    {
        if(sensor.readable())
        {
            *pointer++ = sensor.getc();
            logTrace(*pointer);
            counter--;
            }
        if(counter == 0) {
            return;
            }
        }
    }
    
void writeBuffer(const uint8_t* buffer, uint16_t count)
{
    logInfo( "Sending Data to sensor\n");
    uint8_t* pointer = (uint8_t*)buffer;
    uint16_t counter = count;
    while(1)
    {
        if(sensor.writeable())
        {
            logTrace(*pointer);
            sensor.putc(*pointer++);
            counter--;
            }
        if(counter == 0) {
            return;
            }
        }
    } 

//Validate the received mesurements checksum

bool checkValue(uint8_t *thebuf, uint8_t leng)
{  
  bool receiveflag = false;
  uint16_t receiveSum=0;

  //Don't include the checksum bytes in the sum
  for(int i=0; i<(leng-3); i++){
  receiveSum=receiveSum+thebuf[i];
  }
  receiveSum=receiveSum + 0x42;
 
  if(receiveSum == ((thebuf[leng-2]<<8)+thebuf[leng-1]))  //check the debug data 
  {
    receiveSum = 0;
    receiveflag = true;
  }
  return receiveflag;
}

//Extract the 1 micron particle count from the messaage
uint16_t transmitPM01(uint8_t *thebuf)
{
  uint16_t PM01Val;
  PM01Val=((thebuf[3]<<8) + thebuf[4]); //count PM1.0 value of the air detector module
  return PM01Val;
}

//Extract the 2.5 micron particle count from the messaage
uint16_t transmitPM2_5(uint8_t *thebuf)
{
  uint16_t PM2_5Val;
  PM2_5Val=((thebuf[5]<<8) + thebuf[6]);//count PM2.5 value of the air detector module
  return PM2_5Val;
  }

//Extract the 10 micron particle count from the messaage
uint16_t transmitPM10(uint8_t *thebuf)
{
  uint16_t PM10Val;
  PM10Val=((thebuf[7]<<8) + thebuf[8]); //count PM10 value of the air detector module  
  return PM10Val;
}

int main()
{
    uint8_t dataBuffer[MESSAGE_LEN];
    uint16_t response;
    uint16_t PM01Value=0;     //define PM1.0 value of the air detector module
    uint16_t PM2_5Value=0;        //define PM2.5 value of the air detector module
    uint16_t PM10Value=0;         //define PM10 value of the air detector module
    
    pc.printf("Starting Honeywell Dust Sesor App version %s/n", VERSION);

    //Send start command to the sensor
    writeBuffer(measureCommand, 4);
 /*
 Not geting response from sensor - first characters received are measurement data   
    //Wait for sensors response
    //while(!sensor.readable());
    readBuffer(dataBuffer, 2);
    response = dataBuffer[0] << 8 || dataBuffer[1];

    switch(response) {
        case OK:
        logInfo("Sensor Auto Measurement Started");
        break;
        case BAD:
        logInfo("Sensor rejected Start Measurement Commmand");
        return -1;
        default:
        logInfo("Communication Error: Invalid Sensor Response");
        return -2;
    }
*/    

    //Start continous loop 
    while(1)
    {
       if(sensor.getc() == 0x42){    //start to read when detect 0x42
            readBuffer(dataBuffer,MESSAGE_LEN -1);
        
            if(dataBuffer[0] == 0x4d){
              if(checkValue(dataBuffer, MESSAGE_LEN-1)){
                PM01Value=transmitPM01(dataBuffer); //count PM1.0 value of the air detector module
                PM2_5Value=transmitPM2_5(dataBuffer);//count PM2.5 value of the air detector module
                PM10Value=transmitPM10(dataBuffer); //count PM10 value of the air detector module 
              }
              else {
                  pc.printf("Message checksum error\n");
              }
              
          }           
        }
        //Check for exit request
        if(pc.readable()) {
            char input = pc.getc();
            if(input == 'Q' || input == 'q')
            { 
                writeBuffer(stopCommand, 4);
                pc.printf("Exit request received\n");
                return 0;
            }
        }
// Use MBed wait function instead of Arduino delay loop
      wait_ms(1000);          
          
      pc.printf("PM1.0: %d ug/m3", PM01Value);  
        
      pc.printf("PM2.5: %d ug/m3", PM2_5Value);  
          
      pc.printf("PM10: %d ug/m3", PM10Value);  

      pc.printf("\n");
            
    }
 }