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// filename button.c
// connect a button to DIO pin 1 and ground
// blinks green and red led on the ts-7200 when button is pressed
//
// compile arm-linux-gcc -o button button.c
//
#include<unistd.h>
#include<sys/types.h>
#include<sys/mman.h>
#include<stdio.h>
#include<fcntl.h>
#include<string.h>
int main(int argc, char **argv)
{
volatile unsigned int *PEDR, *PEDDR, *PBDR, *PBDDR, *GPIOBDB;
int i;
unsigned char state;
unsigned char *start;
int fd = open("/dev/mem", O_RDWR | O_SYNC);
start = mmap(0, getpagesize(), PROT_READ | PROT_WRITE, MAP_SHARED, fd,
0x80840000);
PBDR = (unsigned int *)(start + 0x04); // port b
PBDDR = (unsigned int *)(start + 0x14); // port b direction register
PEDR = (unsigned int *)(start + 0x20); // port e data
PEDDR = (unsigned int *)(start + 0x24); // port e direction register
GPIOBDB = (unsigned int *)(start + 0xC4); // debounce on port b
*PBDDR = 0xf0; // upper nibble output, lower nibble input
*PEDDR = 0xff; // all output (just 2 bits)
*GPIOBDB = 0x01; // enable debounce on bit 0
state = *PBDR; // read initial state
while (state & 0x01) // wait until button goes low
{
state = *PBDR; // remember bit 0 is pulled up with 4.7k ohm
}
// blink 5 times, sleep 1 second so it's visible
for (i = 0; i < 5; i++)
{
*PEDR = 0xff;
sleep(1);
*PEDR = 0x00;
sleep(1);
}
close(fd);
return 0;
}
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