ay io test

#include <stdio.h>
#include <string.h>
#include <oscalls.h>
#include <stdlib.h>
#include <intrz80.h>

unsigned char iovalue = 0;

unsigned char scrredraw(void){
    puts("\r\nTest AY IO ports");
    printf("Current values 0x%02X",iovalue);
    return 0;
}
void initMCU(void){
    YIELD();
    OS_SETGFX(6);
    puts("\r\nTest AY IO ports");
}
#define wr_ay_reg(r, v) output(0xfffd,(r));\
                        output(0xbffd,(v))
void main (int argc, char *argv[])
{
    wr_ay_reg(7, 0xc0);
    while(1){
        wr_ay_reg(16, iovalue);
        wr_ay_reg(17, iovalue);
        printf("\rCurrent values 0x%02X",iovalue);
        getchar();
        iovalue ^= 0xff;
    }
}