Week 12 - LED & NES
This week we finished Project 1 critiques, discussed Metal Performance by Steve Dixon, and learned about shift registers and motors.
Lab 6 was all about shift registers following this tutorial. The tutorial gives a lot of good information and even shows a practical use of shift registers through the first Nintendo controller. It explains how the bit information works and what each pin does along with a diagram showing where each one is.
- VCC - power supply for the 74HC595; must be connected to 5V
- SER (Serial Input) - sends data into the shift register one bit at a time
- SRCLK (Shift Register Clock) - clock for the shift-register; positive-edge triggered
- Positive-edge triggered - the bits are pushed in on the rising edge of the clock
- RCLK (Register Clock/Latch) - when pulled high, contents of the shift register are copied into the storage/latch register; last step before seeing output results
- SRCLR (Shift Register Clear) - allows rest of entire shift register, setting all bits to zero; active-low pin
- Active-low- on when connected to no power, off when connected to power
- QA-QH (Output Enable) - output pins
- OE (Output Enable) - functions like normal output pin but is active-low
- QH' - outputs bit 7 which allows you to "daisy-chain" multiple 74HC595s; connect to the SER pin of another 74HC595 allowing them to behave like one piece that has more outputs
The next part of the tutorial was creating the following circuit to allow LEDs transition from one to another in a specific order. My LEDs would turn on, but not all of them, and once they were on it didn't change. I would have to disconnect the power source and reconnect it for anything to change and it was doing as it was supposed to.
