/* Copyright (C) 2011-2014 by Jacob Alexander
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

// ----- Includes -----

// Compiler Includes
#include <Lib/MainLib.h>

// Project Includes
#include <macro.h>
#include <scan_loop.h>
#include <output_com.h>

#include <cli.h>
#include <led.h>
#include <print.h>



// ----- Defines -----

// Verified Keypress Defines
#define USB_TRANSFER_DIVIDER 10 // 1024 == 1 Send of keypresses per second, 1 == 1 Send of keypresses per ~1 millisecond



// ----- Macros -----
#if defined(_at90usb162_) || defined(_atmega32u4_) || defined(_at90usb646_) || defined(_at90usb1286_)
#define CPU_PRESCALE(n)	(CLKPR = 0x80, CLKPR = (n))
#endif



// ----- Variables -----

// Timer Interrupt for flagging a send of the sampled key detection data to the USB host
uint16_t sendKeypressCounter = 0;

// Flag generated by the timer interrupt
volatile uint8_t sendKeypresses = 0;



// ----- Functions -----

inline void usbTimerSetup()
{
// AVR
#if defined(_at90usb162_) || defined(_atmega32u4_) || defined(_at90usb646_) || defined(_at90usb1286_)

	// Setup with 16 MHz clock
	CPU_PRESCALE( 0 );

	// Setup ISR Timer for flagging a kepress send to USB
	// Set to 256 * 1024 (8 bit timer with Clock/1024 prescalar) timer
	TCCR0A = 0x00;
	TCCR0B = 0x03;
	TIMSK0 = (1 << TOIE0);

// ARM
#elif defined(_mk20dx128_) || defined(_mk20dx128vlf5_) || defined(_mk20dx256_)
	// 48 MHz clock by default

	// System Clock Gating Register Disable
	SIM_SCGC6 |= SIM_SCGC6_PIT;

	// Enable Timers
	PIT_MCR = 0x00;

	// Setup ISR Timer for flagging a kepress send to USB
	// 1 ms / (1 / 48 MHz) - 1 = 47999 cycles -> 0xBB7F
	PIT_LDVAL0 = 0x0000BB7F;
	PIT_TCTRL0 = 0x3; // Enable Timer 0 interrupts, and Enable Timer 0

	// Insert the required vector for Timer 0
	NVIC_ENABLE_IRQ( IRQ_PIT_CH0 );
#endif
}


int main()
{
	// Enable CLI
	CLI_init();

	// Setup Modules
	Output_setup();
	Macro_setup();
	Scan_setup();

	// Setup ISR Timer for flagging a kepress send to USB
	usbTimerSetup();

	// Main Detection Loop
	while ( 1 )
	{
		// Process CLI
		CLI_process();

		// Acquire Key Indices
		// Loop continuously until scan_loop returns 0
		cli();
		while ( Scan_loop() );
		sei();

		// Run Macros over Key Indices and convert to USB Keys
		Macro_process();

		// Send keypresses over USB if the ISR has signalled that it's time
		if ( !sendKeypresses )
			continue;

		// Send USB Data
		Output_send();

		// Clear sendKeypresses Flag
		sendKeypresses = 0;
	}
}


// ----- Interrupts -----

// USB Keyboard Data Send Counter Interrupt
#if defined(_at90usb162_) || defined(_atmega32u4_) || defined(_at90usb646_) || defined(_at90usb1286_) // AVR
ISR( TIMER0_OVF_vect )
#elif defined(_mk20dx128_) || defined(_mk20dx128vlf5_) || defined(_mk20dx256_) // ARM
void pit0_isr()
#endif
{
	sendKeypressCounter++;
	if ( sendKeypressCounter > USB_TRANSFER_DIVIDER ) {
		sendKeypressCounter = 0;
		sendKeypresses = 1;
	}

#if defined(_mk20dx128_) || defined(_mk20dx128vlf5_) || defined(_mk20dx256_) // ARM
	// Clear the interrupt flag
	PIT_TFLG0 = 1;
#endif
}