I/O Port for LPC2148

In and Out Port for LPC2148

LPC2148 port acts input for reading data
from P0.28 and P0.29 that connected with push-button switches and resistor pull-up

//————————————————————————————————————————————————————————————————————————//
// Program : Example for test switch
// Description : Test switch at P0.28 and P0.29 for toggle LED at P0.21 and P0.22
// Frequency : Crystal 12 MHz at PLL 5x(CCLK = 60 MHz),PCLK = 30 MHz
// Filename : switch.c
// C compiler : Keil CARM Compiler
//————————————————————————————————————————————————————————————————————————//
#include “lpc214x.h” // Header file for Phillips LPC2148 controller

//—————————————— Function for Initial system clock ————————————————//
void init()
{
PLL0CFG=0x24; // MSEL = 4,PSEL = 2
PLL0FEED=0xAA; // Feed process
PLL0FEED=0x55;
PLL0CON=0x1;
PLL0FEED=0xAA; // Feed process
PLL0FEED=0x55;
while(!(PLL0STAT & 0x400)); // Wait until PLL Locked
PLL0CON=0x3; // Connect the PLL as the clock source
PLL0FEED=0xAA; // Feed process
PLL0FEED=0x55;
MAMCR=0x2; // Enabling MAM and setting number of clocks used
// for Flash memory fetch (4 cclks in this case)
MAMTIM=0x4;
VPBDIV=0x02; // PCLK at 30 MHz
}

/**Function read input P0 **/

char inp0(char _bit) {
unsigned long c;
c = 1<<_bit;
FIO0DIR &= ~c;
return ((FIO0PIN & c)>>_bit);
}

/* Main Function */
void main() {
init();
SCS = 0x03;
FIO0DIR |= 0x00600000;
FIOSET |= 0x00600000;
while(1) {
if (inp0(28) == 0)
{
while(inp0(28)==0);
FIO0PIN ^= (1<<21);
}
if (input(29) == 0)
{
while(inp0(29) == 0);
FIO0PIN ^= 1<<22;
}
}
}