Lecture 20

Question 1

Simple low-power LED

Answer 1

Basic LED (GPIO), resistor needed to limit current supplied

Question 2

7-segment LED

Answer 2

7 x GPIO signals.

MCU implementation

Question 3

High-power RGB LED

Answer 3

Microcontroller still outputs TTL digital signal
PWN to control LED brightness
Additional circuitry used to drive LEDs

Question 4

RGB strip lights

Answer 4

PWM serial interface
REB intensity values for all LEDs are connected on a single wire
Per LED need 24-bits of information.

Question 5

LCD character display

Answer 5

Parallel GPIO interface.
Write data to display, on every falling edge of E (enable) signal.
Requires specific timing between signal changes.

Question 6

VGA = Video Graphics Array

Answer 6

640 x 380 pixels.
RGB signal for each pixel is transmitted as analog V, varied over time.
Clock signals used to indicate start of frame, start of line (HSYNC, VSYNC), and indervidual pixels (pixel clock)

Question 7

HDMI

High-Definition Multimedia Interface

Answer 7

Complicated digital serial interface. Carries video,audio and other data.
Max data rate of 10.46 Gbit/s