Page 111 - ARM Based Microcontroller Projects Using MBED

7.7 PROJECT 4—ROTATING LEDs 97
*********************************************************************
ROTATING LEDS
=============
In this modified version of the program The PortOut statement is used
to configure PORT C. Mask 0x00FF sets PC_0 to PC_7 bits to all 1's so
that all the lower byte of PORT C is used.

Author: Dogan Ibrahim
Date : August 2018
File: LED8-2
************************************************************************/
#include "mbed.h"
PortOut LEDS(PortC, 0x00FF);
int State[] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80};
int main()
{
while(1)
{
for(int k = 0; k < 8; k++) // Do 8 times
{
LEDS = State[k]; // Turn LED ON
wait(0.25); // Wait 250ms
}
}
}

FIG. 7.30 Modified program.

/*******************************************************************
ROTATE LEDS
===========
In this modified program, the BusOut statement is used. The delay
between teh outputs is set to 0.5 second

Author: Dogan Ibrahim
Date : August 2018
File : LED8-3
*******************************************************************/
#include "mbed.h"

BusOut LEDS(PC_0,PC_1,PC_2,PC_3,PC_4,PC_5,PC_6,PC_7);
int main()
{
int k = 0; // First LED
while(1) // Endless loop
{
LEDS = 1 << k; // LED ON
wait(0.5); // Wait 0.5 second
k++; // Increment LED count
if(k == 8)k = 0; // Back to first LED
}
}

FIG. 7.31 Another modified program.