Sample Code mostly for the Mbed

Simple Hello World

#include "mbed.h"

DigitalOut myled(LED1);

int main() {
    while(1) {
        myled = 1;
        puts("Hello!");
        wait(0.2);
        myled = 0;
        wait(1);
    }
}

Servo Control

This lets you move a servo back and forth with s and d keys.

// Hello World to sweep a servo through its full range
// Control a R/C model servo

#include "mbed.h"
Serial pc(USBTX, USBRX); // tx, rx

PwmOut servo(p21);
float pos = 0.0015;

int main() {
    servo.period(0.020);          // servo requires a 20ms period
    pc.printf("Press 's' to turn CCW, 'd' to turn it CW\n\r");

    while(1) {
        char c = pc.getc();
        if((c == 's') && (pos > 0.0005)) {
            pos -= 0.00001;
            // pos = 0.0005;
           servo.pulsewidth(pos);
        }
        if((c == 'd') && (pos < 0.0024)) {
            pos += 0.00001;
            // pos = 0.0024;
            servo.pulsewidth(pos);
        } 
        pc.printf("Pulse= %f ms\n\r", pos);
    }
}

Analog In

This lets you measure a voltage on a pin.

#include "mbed.h"

AnalogIn ain(p20);
Serial pc(USBTX, USBRX); // tx, rx

int main() {
    while (1){
        pc.printf("Analog in= %f V \n\r", 3.306*ain);
        wait(.2);
    }
}

Beeper Sweep

This lets you sweep a Piezo buzzer's frequency though a range with the s and d keys.

// Hello World to sweep a beeper through its full range
// Control a R/C model beeper

#include "mbed.h"
Serial pc(USBTX, USBRX); // tx, rx

PwmOut beeper(p21);
float freq = 1000; // start with  1kHz freq


int main() {
    beeper.period(1/freq);          // beeper requires a 20ms period
    beeper.pulsewidth(0.5/freq);    // and a 50% Duty cycle
    pc.printf("Press 's' to lower, or 'd' to raise the frequency \n\r");

    while(1) {
        char c = pc.getc();
        if((c == 's')) {
            freq -= 50;
            // freq = 0.0005;
            beeper.period(1/freq);
            beeper.pulsewidth(0.5/freq);
        }
        if((c == 'd')) {
            freq += 50;
            // freq = 0.0024;
            beeper.period(1/freq);
            beeper.pulsewidth(0.5/freq);
        }
        if (c == 'm') {  beeper.pulsewidth(0); }
        
        pc.printf("Frequency= %f ms\n\r", freq);
    }
}

LED Brightness Sweep

Cycles the LED brightness smoothly up and down through all 16 levels using the SPI controlled MAX6957ANI+.

#include "mbed.h"

SPI spi(p5, p6, p7); // mosi, miso, sclk
DigitalOut cs(p8);

#define     CONFIG  0x04
#define     GLBCUR  0x02
#define     DISTEST 0x07
#define     PCONF04 0x09
#define     PCONF24 0x0E
#define     PORTS24 0x58

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

int read(int reg) {
    int ret;
    
    reg |= 0x80;
    cs = 0;
     spi.write(reg); spi.write(0);
     cs = 1; cs =0;
     spi.write(0);
     ret =  spi.write(0);
     cs = 1;
     return ret;
}

int write(int add, int data) {
    
    cs = 0;
    spi.write(add); spi.write(data);
    cs = 1;
    return 1;
}

int main() {
    // Setup the spi for 8 bit data, high steady state clock,
    // second edge capture, with a 1MHz clock rate
    spi.format(8,3);
    spi.frequency(20000000);

    int ret;
   
    write(CONFIG, 1); // Enable the Max 6957
    write(PCONF24, 0); // Set p24 - p27 to led drivers
    write(PORTS24, 0x0f); // Turn on p24 - p27
    // write(DISTEST, 1); // Enable display test

    ret = read(CONFIG);
    pc.printf("CONFIG register = 0x%X\n\r", ret);
    ret = read(PCONF24);
    pc.printf("PCONF24 register = 0x%X\n\r", ret);
        
   int cur = 0, inc = 1;
   while (1) {
    for(;(inc == 1 && cur <= 15) || (inc == -1 && cur >=0); cur+=inc) {
        write(GLBCUR, cur);
        wait(.05);
    }
    inc *=-1; cur+=inc;
    }
    write(DISTEST, 0); // Disable display test
}

Ether Port Test

Prints the MAC address of any received packets

#include "mbed.h"

Ethernet eth;
Serial pc(USBTX, USBRX);

int main() {
    char buf[0x600];

    while(1) {
        int size = eth.receive();
        if(size > 0) {
            eth.read(buf, size);
            pc.printf("Destination:  %02X:%02X:%02X:%02X:%02X:%02X\n\r",
                    buf[0], buf[1], buf[2], buf[3], buf[4], buf[5]);
            pc.printf("Source: %02X:%02X:%02X:%02X:%02X:%02X\n\r",
                    buf[6], buf[7], buf[8], buf[9], buf[10], buf[11]);
        }

        wait(1);
    }
}

-- ClifCox - 19 Nov 2011