* ButtonLED
* This file contains the functions that control the button game LEDs.
* The LEDs are controlled using a 74HC595 (output) shift register.

* Lights an LED corresponding to a specific button.

buttonInput
	Param: uint8_t called buttonNum, specifies which LED(s) should light up at a given time
	Returns: nothing

	1) for each of the 8 LEDSs in the game
		if the buttonNum corresponding to a specific LED is equal to 1
			turn that LED on by calling setSerial function and passing it a 1
		else
			turn that LED off by calling setSerial function and passing it a 0

		pulse the serial clock using the sclkPulse function
	    end for

	2) pulse the serial clock using the rclkPulse function

end buttonInput


* Turns on all button LEDs.

buttonLightsOn
takes no parameters, returns nothing

	1) for each of the 8 LEDSs in the game
		turn that LED on by calling setSerial function and passing it a 1
		pulse the serial clock using the sclkPulse function
	    end for

	2) pulse the serial clock using the rclkPulse function


end buttonLightsOn


* Sets the SER (data) line of the output shift register. Private function.

setSerial
	Param: uint8_t input (data to shift in, i.e. 0 or 1)
	Return: nothing

	1) if the input passed to setSerial is a 1
		set the serial register pin (SREG_SER_PIN) high; 
	2) else if the input passed to setSerial is a 0
		set the serial register pin (SREG_SER_PIN) low; 
	end if

end setSerial


* Pulses the shift clock. Private function.

sclkPulse
takes no parameters, returns nothing

	1) set the serial clock pin (SREG_SCLK_PIN) high
	2) pause using the delay function
	3) set the serial clock pin (SREG_SCLK_PIN) low
end sclkPulse


* Pulses the register clock. Private function.

rclkPulse
	1) set the register clock pin (SREG_RCLK_PIN) high;
	2) pause using the delay function
	3) set the register clock pin (SREG_RCLK_PIN) low;
end rclkPulse


* Delays for a short period of time to allow for clock pulses to be detected.
* Private function.

delay
takes no parameters, returns nothing
	
	1) declare and set a dummy variable equal to a number
	2) for 100 times (to stall)
		add 1 to the dummy variable
	  end for
end delay