hid-arcade/firmware/main.c

#include <avr/io.h>
#include <avr/wdt.h>
#include <avr/interrupt.h>  /* for sei() */
#include <util/delay.h>     /* for _delay_ms() */
#include <avr/pgmspace.h>   /* required by usbdrv.h */
#include "usbdrv.h"

#define NES_LATCH   (1<<PB4)
#define NES_CLOCK   (1<<PB3)
#define NES_DATA    (1<<PB5)

#define NES_LATCH_LOW()	PORTB &= ~(NES_LATCH);
#define NES_LATCH_HIGH()	PORTB |= NES_LATCH;
#define NES_CLOCK_LOW()	PORTB &= ~(NES_CLOCK);
#define NES_CLOCK_HIGH()	PORTB |= NES_CLOCK;
#define NES_GET_DATA()		(PINB & NES_DATA)

static uchar g_report_buffer[3]; 
static uchar g_idle_rate;

static uchar g_nes_buttons;

PROGMEM char usbHidReportDescriptor[49] =
{
    0x05, 0x01,                    // USAGE_PAGE (Generic Desktop)
    0x09, 0x05,                    // USAGE (Game Pad)
    0xa1, 0x01,                    //   COLLECTION (Application)
    0x09, 0x01,                    //     USAGE (Pointer)
    0xa1, 0x00,                    //     COLLECTION (Physical)
    0x09, 0x30,                    //       USAGE (X)
    0x09, 0x31,                    //       USAGE (Y)
    0x15, 0x00,                    //       LOGICAL_MINIMUM (0)
    0x26, 0xff, 0x00,				//      LOGICAL_MAXIMUM (255)
    0x75, 0x08,                    //       REPORT_SIZE (8)
    0x95, 0x02,                    //       REPORT_COUNT (2)
    0x81, 0x02,                    //       INPUT (Data,Var,Abs)
    0xc0,                          //     END_COLLECTION
    0x05, 0x09,                    //     USAGE_PAGE (Button)
    0x19, 0x01,                    //     USAGE_MINIMUM (Button 1)
    0x29, 0x04,                    //     USAGE_MAXIMUM (Button 4)
    0x15, 0x00,                    //     LOGICAL_MINIMUM (0)
    0x25, 0x01,                    //     LOGICAL_MAXIMUM (1)
    0x75, 0x01,                    //     REPORT_SIZE (1)
    0x95, 0x04,                    //     REPORT_COUNT (4)
    0x81, 0x02,                    //     INPUT (Data,Var,Abs)
	0x75, 0x01,                    //     REPORT_SIZE (1)
	0x95, 0x04,                    //     REPORT_COUNT (4)
	0x81, 0x03,                    //     INPUT (Constant,Var,Abs)
    0xc0,                          //   END_COLLECTION
};

void nes_update(void) {
	g_nes_buttons = 0;
	
	// Tell the controller to latch the button states
	NES_LATCH_HIGH();

	// Read the A button - what a hack
	_delay_us(2);
	g_nes_buttons |= !NES_GET_DATA() << 0;

	_delay_us(10);
	NES_LATCH_LOW();

	// Wait 6 more microseconds...
	_delay_us(6);

	// Read all the rest of the buttons...
	uchar i;
	for (i = 1; i < 8; i++)
	{
		//Pulse clock
		NES_CLOCK_HIGH();
		_delay_us(6);
		NES_CLOCK_LOW();

		g_nes_buttons |= (!NES_GET_DATA() << i);

		// Wait the low part of the cycle
		_delay_us(6);
	}

	// Let's pulse out one last time... Just like the NES does
	NES_CLOCK_HIGH();
	_delay_us(6);
	NES_CLOCK_LOW();
}

void usb_build_report(void)
{
	uchar y, x;
	
	x = 128;
	y = 128;
	
	if (g_nes_buttons & (1 << 6))
		x = 0;
	if (g_nes_buttons & (1 << 7))
		x = 255;
	
	if (g_nes_buttons & (1 << 4))
		y = 0;
	if (g_nes_buttons & (1 << 5))
		y = 255;
	
	g_report_buffer[0] = x;
	g_report_buffer[1] = y;
	g_report_buffer[2] = g_nes_buttons;
}

usbMsgLen_t usbFunctionSetup(uchar data[8])
{
usbRequest_t    *rq = (void *)data;

    /* The following requests are never used. But since they are required by
     * the specification, we implement them in this example.
     */
    if((rq->bmRequestType & USBRQ_TYPE_MASK) == USBRQ_TYPE_CLASS){    /* class request type */
        if(rq->bRequest == USBRQ_HID_GET_REPORT){  /* wValue: ReportType (highbyte), ReportID (lowbyte) */
            /* we only have one report type, so don't look at wValue */
            usbMsgPtr = (void *)&g_report_buffer;
            return sizeof(g_report_buffer);
        }else if(rq->bRequest == USBRQ_HID_GET_IDLE){
            usbMsgPtr = &g_idle_rate;
            return 1;
        }else if(rq->bRequest == USBRQ_HID_SET_IDLE){
            g_idle_rate = rq->wValue.bytes[1];
        }
    }else{
        /* no vendor specific requests implemented */
    }
    return 0;   /* default for not implemented requests: return no data back to host */
}


void adcInit(){

DDRC=0;
DDRB=0;
PORTC=0xff;
PORTB=0xff;
//PORTB=(1<<PB1)|(1<<PB2);
//ADMUX=(1<<REFS0);
//ADCSRA=(1<<ADEN)|(1<<ADPS0)|(1<<ADPS1)|(1<<ADPS2);

}

/* ------------------------------------------------------------------------- */

int main(void)
{
    wdt_enable(WDTO_1S);
    /* Even if you don't use the watchdog, turn it off here. On newer devices,
     * the status of the watchdog (on/off, period) is PRESERVED OVER RESET!
     */
    /* RESET status: all port bits are inputs without pull-up.
     * That's the way we need D+ and D-. Therefore we don't need any
     * additional hardware initialization.
     */
    usbInit();
    usbDeviceDisconnect();  /* enforce re-enumeration, do this while interrupts are disabled! */
    uchar i = 0;
    while(--i){             /* fake USB disconnect for > 250 ms */
        wdt_reset();
        _delay_ms(1);
    }
	
	DDRB = NES_LATCH | NES_CLOCK;
	
    usbDeviceConnect();
    sei();
    for(;;) { //main event loop
        wdt_reset();
        usbPoll();
		
		nes_update();
		
		if(usbInterruptIsReady()){
            usb_build_report();
            usbSetInterrupt(g_report_buffer, sizeof(g_report_buffer));
        }
    }
    return 0;
}