Marout Yasuo Sluijter-Borms

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8 years, 8 months ago.

enumerate IO pins.

Hi,

I' m trying to optimize my "hello_world code:

int main()
{
    uart1.baud(921600);
    while(1) {
        myled1 = 1;
        uart1.printf("LED1 aan\r");
        wait(0.2);
        myled1 = 0;
        myled2 = 1;
        uart1.printf("LED2 aan\r");
        wait(0.2);
        myled2 = 0;
        myled3 = 1;
        uart1.printf("LED3 aan\r");
        wait(0.2);
        myled3 = 0;
        myled4 = 1;
        uart1.printf("LED4 aan\r");
        wait(0.2);
        myled4 = 0;
    }
}       //  endmain

How can I implement a for() loop to sequentially perform the same action: I tried:

/*  Libraries en classes insluiten  */
#include "mbed.h"

/*  Definieer seriële poorten       */
Serial uart1( p9, p10);            //  tx, rx communicatie via seriele poort

/*  Definieer digitale IO           */
DigitalOut myled1(LED1);
DigitalOut myled2(LED2);
DigitalOut myled3(LED3);
DigitalOut myled4(LED4);

/*  Start hoofprogramma             */

int main() 
{
    uart1.baud(921600);
    while(1) {
        for ( int i = 1; i < 5; ++i) {
            myled[i] = 1;
            uart1.printf("LED %i aan\r", i);
            wait(0.2);
            myled[i] = 0;
        }
    }
}       //  endmain

Which of course doesn't work. How do I mplement such a feature? Can I define a vector with the four leds in it?

1 Answer

Wim Huiskamp
8 years, 8 months ago.

Yes, you can define an array of LED DigitalOut pins or you can use the BusOut type. See here for a similar example.

Accepted Answer

Thank you Wim,

That was exactly what I was looking for.

I was already irritating myself with a solution using PortOut() with integer constants holding binary patterns for every separate LED. But this is far easier.

Can I address LEDS and PINS on a LPC1768 also using the Px.y syntax where X is port and Y is pin, like some other mbed controllers do?

Regards, marout

posted by Marout Yasuo Sluijter-Borms 01 May 2016

You can select any LPC1768 pin by using pinnames like Px_y. For example P0_1 for Port 0, pin 1. The pinnames shown on the LPC1768 platform page (eg p9, p10, I2C_SDA, USB_TX etc) are just shortcuts for the actual pinnames. These shortcuts are defined in mbed source PinNames.h.

posted by Wim Huiskamp 01 May 2016