#include "mbed.h"

// DS18B20 converted to run on mbed

#define TEMP_PIN  PTC9

Serial pc(USBTX, USBRX); // tx, rx

DigitalInOut temperature_pin(TEMP_PIN);

void OneWireReset() { // reset.  Should improve to act as a presence pulse
    temperature_pin.output();
    temperature_pin = 0;     // bring low for 500 us
    wait_us(500);
    temperature_pin.input();
    wait_us(500);
}

void OneWireOutByte(unsigned char d) { // output byte d (least sig bit first).
    for(int n=8; n!=0; n--) {
        if ((d & 0x01) == 1) { // test least sig bit
            temperature_pin.output();
            temperature_pin = 0;
            wait_us(5);
            temperature_pin.input();
            wait_us(60);
        } else {
            temperature_pin.output();
            temperature_pin = 0;
            wait_us(60);
            temperature_pin.input();
        }

        d=d>>1; // now the next bit is in the least sig bit position.
    }

}

unsigned char OneWireInByte() { // read byte, least sig byte first
    unsigned char d = 0, b;
    for (int n=0; n<8; n++) {
        temperature_pin.output();
        temperature_pin = 0;
        wait_us(5);
        temperature_pin.input();
        wait_us(5);
        b = temperature_pin;
        wait_us(50);
        d = (d >> 1) | (b << 7); // shift d to right and insert b in most sig bit position
    }
    return d;
}

int main() {
    int HighByte, LowByte, TReading, SignBit, Tc_100, Whole, Fract;
    pc.printf("mbed 1 wire interface simple test!\r\n");
    temperature_pin.output();
    temperature_pin = 0;
    temperature_pin.input();  // sets the digital pin as input (logic 1) make sure external pullup resistor 4K7
    wait(1);
    pc.printf("temperature measurements:\r\n");

    while (1) {
        OneWireReset();
        OneWireOutByte( 0xcc);  //Skip ROM command
        OneWireOutByte( 0x44); // perform temperature conversion, strong pullup for one sec

        OneWireReset();
        OneWireOutByte( 0xcc);
        OneWireOutByte( 0xbe);   //Read Scratchpad

        LowByte = OneWireInByte();
        HighByte = OneWireInByte();
        TReading = (HighByte << 8) + LowByte;
        SignBit = TReading & 0x8000;  // test most sig bit
        if (SignBit) { // negative
            TReading = (TReading ^ 0xffff) + 1; // 2's comp
        }
        Tc_100 = (6 * TReading) + TReading / 4;    // multiply by (100 * 0.0625) or 6.25

        Whole = Tc_100 / 100;  // separate off the whole and fractional portions
        Fract = Tc_100 % 100;

        if (SignBit) { // If its negative
            pc.printf("-");
        }
        pc.printf("%d", Whole);
        pc.printf(".");
        if (Fract < 10) {
            pc.printf("0");
        }
        pc.printf("%d", Fract);
        pc.printf("\r\n");
       
        wait(5);         // 5 second delay.  Adjust as necessary
    }
}

CMSIS target isn't defined for the Kl25z, I dont understand what is the work out for this problem? <<code>> #include "mbed.h" // DS18B20 converted to run on mbed #define TEMP_PIN PTC9 Serial pc(USBTX, USBRX); // tx, rx DigitalInOut temperature_pin(TEMP_PIN); void OneWireReset() { // reset. Should improve to act as a presence pulse temperature_pin.output(); temperature_pin = 0; // bring low for 500 us wait_us(500); temperature_pin.input(); wait_us(500); } void OneWireOutByte(unsigned char d) { // output byte d (least sig bit first). for(int n=8; n!=0; n--) { if ((d & 0x01) == 1) { // test least sig bit temperature_pin.output(); temperature_pin = 0; wait_us(5); temperature_pin.input(); wait_us(60); } else { temperature_pin.output(); temperature_pin = 0; wait_us(60); temperature_pin.input(); } d=d>>1; // now the next bit is in the least sig bit position. } } unsigned char OneWireInByte() { // read byte, least sig byte first unsigned char d = 0, b; for (int n=0; n<8; n++) { temperature_pin.output(); temperature_pin = 0; wait_us(5); temperature_pin.input(); wait_us(5); b = temperature_pin; wait_us(50); d = (d >> 1) | (b << 7); // shift d to right and insert b in most sig bit position } return d; } int main() { int HighByte, LowByte, TReading, SignBit, Tc_100, Whole, Fract; pc.printf("mbed 1 wire interface simple test!\r\n"); temperature_pin.output(); temperature_pin = 0; temperature_pin.input(); // sets the digital pin as input (logic 1) make sure external pullup resistor 4K7 wait(1); pc.printf("temperature measurements:\r\n"); while (1) { OneWireReset(); OneWireOutByte( 0xcc); //Skip ROM command OneWireOutByte( 0x44); // perform temperature conversion, strong pullup for one sec OneWireReset(); OneWireOutByte( 0xcc); OneWireOutByte( 0xbe); //Read Scratchpad LowByte = OneWireInByte(); HighByte = OneWireInByte(); TReading = (HighByte << 8) + LowByte; SignBit = TReading & 0x8000; // test most sig bit if (SignBit) { // negative TReading = (TReading ^ 0xffff) + 1; // 2's comp } Tc_100 = (6 * TReading) + TReading / 4; // multiply by (100 * 0.0625) or 6.25 Whole = Tc_100 / 100; // separate off the whole and fractional portions Fract = Tc_100 % 100; if (SignBit) { // If its negative pc.printf("-"); } pc.printf("%d", Whole); pc.printf("."); if (Fract < 10) { pc.printf("0"); } pc.printf("%d", Fract); pc.printf("\r\n"); wait(5); // 5 second delay. Adjust as necessary } } <</code>>

I think there is nothing specialised done that would complicate stuff ,just some regular bit shifting in and out and for that also inbuilt functions are made and no external library is used!