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;

__sfr __at 0x30 ioKEY;
__sfr __at 0x38 ioKEYint;
__sfr __at 0x3c ioKEYedge;

uint8_t memID[8];
uint8_t interrupt_count[2];

// uart
uint8_t uart_read_next = 0;
uint8_t uart_read_avail = 0;
uint8_t uart_read[128];
void interrupt_1(void) __critical __interrupt(1) {
    uint8_t data;
    uint8_t valid;
    interrupt_count[0] += 1;
    while (true) {
        data = ioSerialData;
        valid = ioSerialRValid;
        if (valid & (1 << 7)) {
            if (uart_read_avail < 128) {
                uint8_t i = uart_read_next + uart_read_avail;
                i %= 128;
                uart_read[i] = data;
                uart_read_avail++;
            }
        } else {
            break;
        }
    }
}

// key
uint8_t waitkey[2] = {0, 0};
void interrupt_2(void) __critical __interrupt(2) {
    uint8_t data;
    data = ioKEYedge;
    ioKEYedge = 0;
    interrupt_count[1] += 1;

    if (data & 0b01)
        waitkey[0] = 1;
    if (data & 0b10)
        waitkey[1] = 1;
}

void wait_for_key(int i) {
    while (!waitkey[i]) {
        __asm__("halt");
    }
    waitkey[i] = 0;
}

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

char getchar(void) {
    char c;
    while (uart_read_avail == 0) {
        __asm__("halt");
    }
    c = uart_read[uart_read_next];
    uart_read_next += 1;
    uart_read_next %= 128;
    uart_read_avail--;
    return c;
}

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() {
    uint8_t flags;

    interrupt_count[0] = 0;
    interrupt_count[1] = 0;
    copy_system_id();

    flags = ioSerialEnable;
    ioSerialEnable = flags | 1;
    ioKEYint = 0b11;

    __asm__("ei");

    ioLED = 0;
    while (true) {
        wait_for_key(1);
        ioLED += 1;
        //printf("set LEDs to: 0x%02x", ioLED);
    }
}