Tx (Oil Temp) - STM32 NUCLEO32-303K8

/*
The code below is for the transmission NUCLEO
Written by Riccardo Geraci
University of Wolverhampton
Embedded System Design: Developing a CAN BUS diagnostics module for a car
Oct 2018 - April 2019
Research Srcs: https://os.mbed.com/users/WiredHome/notebook/can---getting-started/

Averaging is used to filter out the 'wiggle' from the LM35's output. When the code is first
compiled there are no samples
*/

#include "mbed.h" // Mbed library

bool DEBUG_MODE = false; //Bool used to shows printf statements to the console

Ticker ticker; //Ticker object used for looping interrupt
CAN can(PA_11, PA_12); //rx, tx, CAN object with the rx and tx pins

DigitalOut tx_can_stat_led(PA_10); //Led on the PCB used for showing can activity
DigitalOut tx_power_stat_led(PA_9); //Led on the PCB used for showing the the pcb is powered

AnalogIn analog_value(PA_0); //init pin for lm35 output

const int calib = 28; //calibration constant to subtract from the
//sensed temperature to match actual temperature

float meas; //variable to hold the analogue voltage from pin PA_0
float temp; //variable to hold the temperature in C after ADC
float averageTemp; //variable to hold the average temperature
float temps[8]; //Array with a length of 8 used to take the average temperature
int position = 0; //variable used to cycle through temps array later

float getLM35Temperature(){ //function to return the LM35's temperature

        meas = analog_value.read(); //Set the meas variable to signal coming in PA_0
        temp = ((meas*5000/10) - calib); //Convert the analogue value 0 to 1 to 0 to 5.
        //Divided by 10 to get 1 degree output, subtracting the calib constant to bring
        //the temperature to the correct range

        temps[position] = temp; //Set nth position of the temps array to the current
        //temperature after conversion

        //To avoid going outside the bounds of the array, the position variable is reset each
        //time is reaches 7
        if (position==7) {
            position =0;
        } else {
            position++;
        }

        averageTemp = 0; //Reset the averageTemp variable so the
        //last average doesn't affect the current average


        for (int i=0; i<8; i++) {
            averageTemp += temps[i] /8; //loop throught the 8 temperature readings
            //and take the average
        }

    if (DEBUG_MODE){ //Lines used for debugging, display on the console via serial
         //led = temp > 21; //Light the led when tempature passes 21^C
         printf("volts=%f\ttemperature = %.0f^C\taverage= %.0f^C\r\n", meas, temp, averageTemp);
         wait(.01);
        }

        return averageTemp; //When the getLM35Temperature() function is called
        //this is the value that will be given back, or subsituted

   // }
}

void sendCANMsg(){ //function to send lm35 temperature as a CAN message
   char currTemp = getLM35Temperature(); //Variable to hold the average temperature
    if(can.write(CANMessage(1337, &currTemp, 1))){  //(Random Identifier 11-bit defaultly, pointer to data, num of bits to send)
    //above returns true if msg successfully sent (network good, outbound buffer not full, etc)
    if (DEBUG_MODE){
        printf("Message sent (temperature): %d\r\n", currTemp); //Debug code for console
        }
        wait(0.2); //delay to stop bus flooding with 1337 msg, hogging, allows other msgs to have a chance

    tx_can_stat_led = !tx_can_stat_led; // Blink the CAN_LED to show activity
    }
}

int main() //Main entry point function required by C/C++
{
    tx_power_stat_led = 1; //Show the power led of the PCB
    ticker.attach(&sendCANMsg, 1); //reccuring interrupt, repeating every 1 second
}