main.c

#include <stdbool.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>

__sfr __at 0x00 ioLED;

__sfr __at 0x10 ioID0;
__sfr __at 0x11 ioID1;
__sfr __at 0x12 ioID2;
__sfr __at 0x13 ioID3;
__sfr __at 0x14 ioID4;
__sfr __at 0x15 ioID5;
__sfr __at 0x16 ioID6;
__sfr __at 0x17 ioID7;

__sfr __at 0x20 ioSerialData;
__sfr __at 0x21 ioSerialRValid;
__sfr __at 0x22 ioSerialRAvailL;
__sfr __at 0x23 ioSerialRAvailH;

__sfr __at 0x24 ioSerialEnable;
__sfr __at 0x25 ioSerialInterrupt;
__sfr __at 0x26 ioSerialWSpaceL;
__sfr __at 0x27 ioSerialWSpaceH;

volatile __at 0x8000 uint8_t memID[8];

void putchar(char c) {
    ioSerialData = c & 0xff;
}

char getchar(void) {
    uint8_t data;
    uint8_t valid;
    while (true) {
        data = ioSerialData;
        valid = ioSerialRValid;
        if (valid & (1 << 7))
            return data;
    }
}

void sleep(uint8_t amt) {
    while (amt > 0) {
        uint16_t counter = 0xffff;
        while (counter > 0)
            counter--;
        amt--;
    }
}

void copy_system_id(void) {
    memID[0] = ioID0;
    memID[1] = ioID1;
    memID[2] = ioID2;
    memID[3] = ioID3;
    memID[4] = ioID4;
    memID[5] = ioID5;
    memID[6] = ioID6;
    memID[7] = ioID7;
}

void main() {
    char buffer[64];
    unsigned int val;

    copy_system_id();

    while (true) {
        printf("set LEDs to: ");
        gets(buffer);
        val = atoi(buffer);
        val &= 0xff;
        printf("setting LEDs to 0x%02x\n", val);
        ioLED = val;
    }
}