gameport.c

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#include <eZ8.h>             // special encore constants, macros and flash routines
#include <sio.h>             // special encore serial i/o routines
#include "gameport.h"
#include "ansi.h"

unsigned int readADC(unsigned char channel) { // Read a specific analog channel
    unsigned char inHigh, inLow;
    unsigned int ADC_data;

    ADCCTL = 0x80 | 0x20 | (channel & 0x0F); // Enable ADC on the selected channel and use external voltage (3.3V) as VREF
    while (ADCCTL & 0x80); // Wait for conversion to be completed
    inHigh = ADCD_H; // ADC high byte
    inLow = ADCD_L; // ADC low low byte
    ADC_data = ((unsigned int)inHigh << 2)| inLow >> 6; // ADC output word

    return ADC_data;
}

void initGameport() { // Initialize the steering wheel's digital buttons and analog wheel and pedals
    PBDD = (1 << 5) | (1 << 4) | (1 << 3) | (1 << 2); // Use PB2, PB3, PB4 and PB5 as digial inputs
    PBAF = (1 << 1) | (1 << 0); // Use PB0 and PB1 for ADC conversion
}

unsigned char getGameportButtons() { // Read the digital buttons
    return (((~PBIN) & 0x3C) >> 2);
}

char readSteeringWheel() { // Read the steering wheel, this will output a value that can be directly used with moveStriker()
    int val = readADC(1);

    //gotoxy(50,10);
    //printf("Val: %04d",val);

    // The driving wheel is not linear therefor this table is needed
    if (val > 1000)
        return -6; // We will move it more aggressively to the side
    else if (val > 796)
        return -4;
    else if (val > 712)
        return -2;
    else if (val > 610)
        return -1;
    else if (val > 570)
        return 0;
    else if (val > 500)
        return 1;
    else if (val > 466)
        return 2;
    else if (val > 440)
        return 4;
    else
        return 6;
}