Anthony Barison / Mbed 2 deprecated GPIO_Hello_World

An example of how to initialize p20 as GPIO.

Dependencies:   mbed

main.cpp@1:f0b14fe7874e, 2012-08-30 (annotated)

Committer:
a_baris
Date:
Thu Aug 30 12:06:20 2012 +0000
Revision:
1:f0b14fe7874e
Parent:
0:4652951bde46 
GPIO Hello World

Who changed what in which revision?

UserRevisionLine numberNew contents of line
a_baris 1:f0b14fe7874e 1 /* Copyright (c) 2012 Anthony Barison, MIT License
a_baris 1:f0b14fe7874e 2 *
a_baris 1:f0b14fe7874e 3 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
a_baris 1:f0b14fe7874e 4 * and associated documentation files (the "Software"), to deal in the Software without restriction,
a_baris 1:f0b14fe7874e 5 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
a_baris 1:f0b14fe7874e 6 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
a_baris 1:f0b14fe7874e 7 * furnished to do so, subject to the following conditions:
a_baris 1:f0b14fe7874e 8 *
a_baris 1:f0b14fe7874e 9 * The above copyright notice and this permission notice shall be included in all copies or
a_baris 1:f0b14fe7874e 10 * substantial portions of the Software.
a_baris 1:f0b14fe7874e 11 *
a_baris 1:f0b14fe7874e 12 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
a_baris 1:f0b14fe7874e 13 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
a_baris 1:f0b14fe7874e 14 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
a_baris 1:f0b14fe7874e 15 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
a_baris 1:f0b14fe7874e 16 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
a_baris 1:f0b14fe7874e 17 */
a_baris 1:f0b14fe7874e 18
a_baris 0:4652951bde46 19 /*
a_baris 0:4652951bde46 20 This simple program is written has an example to show how pins of
a_baris 0:4652951bde46 21 mbed board can be programmed without the high-level abstraction of the
a_baris 0:4652951bde46 22 class DigitalOut.
a_baris 0:4652951bde46 23
a_baris 0:4652951bde46 24 References:
a_baris 0:4652951bde46 25 http://www.nxp.com/documents/user_manual/UM10360.pdf
a_baris 0:4652951bde46 26
a_baris 0:4652951bde46 27 Author: Anthony Barison
a_baris 0:4652951bde46 28 First release on: 30/08/2012
a_baris 0:4652951bde46 29 Last release on: 30/08/2012
a_baris 0:4652951bde46 30 */
a_baris 0:4652951bde46 31
a_baris 0:4652951bde46 32 #include <stdio.h>
a_baris 0:4652951bde46 33
a_baris 0:4652951bde46 34 /* pin 20 on the mbed board is memory mapped to port P1.31 of LPC1768
a_baris 0:4652951bde46 35 which I have defined as preprocessor directive. The value can be used as a mask to
a_baris 0:4652951bde46 36 read and write the status of "p20" */
a_baris 0:4652951bde46 37
a_baris 0:4652951bde46 38 #define PIN_20 0x80000000 /* this is the mask to be used in referring to p20 on the mbed board */
a_baris 0:4652951bde46 39
a_baris 0:4652951bde46 40 #define FIO1DIR (*((volatile unsigned int *) 0x2009C020)) /* output enable register */
a_baris 0:4652951bde46 41 #define FIO1CLR (*((volatile unsigned int *) 0x2009C03C)) /* clear output data register */
a_baris 0:4652951bde46 42 #define FIO1SET (*((volatile unsigned int *) 0x2009C038)) /* set output data register */
a_baris 0:4652951bde46 43
a_baris 0:4652951bde46 44 //volatile unsigned int *ClearOutputDataReg = (unsigned int *)0xfffff434;
a_baris 0:4652951bde46 45
a_baris 0:4652951bde46 46 int main()
a_baris 0:4652951bde46 47 {
a_baris 0:4652951bde46 48 int state = 0; /* state variable used as store of user input */
a_baris 0:4652951bde46 49
a_baris 0:4652951bde46 50 /* p20 initialization */
a_baris 0:4652951bde46 51 FIO1DIR = PIN_20; /* enable p20 as an output pin */
a_baris 0:4652951bde46 52 FIO1CLR = PIN_20; /* set 0 to p20 as a default value */
a_baris 0:4652951bde46 53
a_baris 0:4652951bde46 54 printf( "\r\nGPIO\r\nPossible inputs\r\n" );
a_baris 0:4652951bde46 55 printf( "0\tset p20 to 0\r\n" );
a_baris 0:4652951bde46 56 printf( "1\tset p20 to 0\r\n" );
a_baris 0:4652951bde46 57 printf( "-1\tterminate program\r\n\r\n" );
a_baris 0:4652951bde46 58
a_baris 0:4652951bde46 59
a_baris 0:4652951bde46 60 while(1) {
a_baris 0:4652951bde46 61
a_baris 0:4652951bde46 62
a_baris 0:4652951bde46 63 /* read user input from terminal */
a_baris 0:4652951bde46 64 printf( "State = ");
a_baris 0:4652951bde46 65 scanf( "%i", &state );
a_baris 0:4652951bde46 66 printf( "%i\r\n", state);
a_baris 0:4652951bde46 67
a_baris 0:4652951bde46 68
a_baris 0:4652951bde46 69 /* */
a_baris 0:4652951bde46 70 if( state == 0 )
a_baris 0:4652951bde46 71 FIO1CLR = PIN_20; /* p20 = 2 */
a_baris 0:4652951bde46 72 else if (state == 1)
a_baris 0:4652951bde46 73 FIO1SET = PIN_20; /* p20 = 1 */
a_baris 0:4652951bde46 74 else if (state == -1)
a_baris 0:4652951bde46 75 return 0; /* terminate program */
a_baris 0:4652951bde46 76 else
a_baris 0:4652951bde46 77 continue;
a_baris 0:4652951bde46 78 }
a_baris 0:4652951bde46 79 }