Shift Out

In this lab we learned how shift registers work and how they can be used to control eight outputs at a time while taking up only a few pins on your micro controller.  This is done using a thing called "synchronous serial communication" which allows you to pulse one pin up and then down allowing you to communicate a data byte to the register bit by bit.  Once the whole byte is transmitted the HIGH, LOW messages located in each bit are then transmitted to its corresponding output pin.  Here is a diagram of the shift register we used for the lab:

 

	PINS 1-7, 15	Q0 " Q7	Output Pins
	PIN 8	GND	Ground, Vss
	PIN 9	Q7"	Serial Out
	PIN 10	MR	Master Reclear, active low
	PIN 11	SH_CP	Shift register clock pin
	PIN 12	ST_CP	Storage register clock pin (latch pin)
	PIN 13	OE	Output enable, active low
	PIN 14	DS	Serial data input
	PIN 16	Vcc	Positive supply voltage

 

Our overall goal for this lab was to control a seven segment LED counter using .  We had a few problems while trying to figure out what pins controlled what on the counter but after we discovered that it was a common anode counter it was smooth from then on.  We were able to control the counter by using only 3 pins in our arduino.