synth/uart/ledctrl.c

#include "led.h"
#include "uart.h"

#define uart0 ((struct uart*)0xc010)

int main() {
  int c;
  int led = 0;

  while (1) {
    led_write(1 << led);
    c = uart_read(uart0);

    if (c == 'a') {
      led++;
    } else if (c == 'd') {
      led--;
    }

    if (led == 8) {
      led = 0;
    } else if (led < 0) {
      led = 7;
    }
  }
}