Bilbao Maker Faire October 2018 FPGA beginner's workshop

Shortlink to this documentation: http://bit.ly/bbmf-fpga. Viewing the documentation online allows you to click links more easily!

Presentation

Materials

Workshop uses the IceBreaker board Soon to be available on CrowdSupply

Software Setup

• Install Icestudio
• Install the workshop package

Switching between collections in Icestudio

Installing and changing collections in Icestudio

Challenges

LEDS on

connect the boards LEDs to the 1 and 0 bits.

Solution: examples -> LEDS -> simple

Use more blocks to turn on other LEDs on the board.

Buttons

Instead of using a 1 or 0 bit block, use a button to turn on and off an LED

In the default collection, add a logic -> gate -> not to invert the button.

LEDs blinking

Add a clock input by adding a basic -> input block and setting it's name and input to CLK. Attach the clk to an LED. Is the LED blinking? Maybe it's too fast! The clock is 12 million times per second!

To slow the clock down, add a logic -> sequential -> Prescalar22 from the default collection. The Prescalar22 block needs to go between the clk input and the LED output.

Button combo

Use a combination of buttons to light LED

In the default collection, use Logic -> Gate -> And to build a circuit that turns on an LED when button 1 AND button2 are pressed.

Solution: Examples -> Buttons -> button logic

Try other logic combinations, for example:

• LED on when button1 AND button2 AND button3
• LED on when (button1 AND button2) OR button3

LEDs blinking at different rates

Using the Bilbao collection, load Examples -> LED -> different rates.

• Try changing the number in the compare box to change the rate of the LED.
• How does this differ from changing the PrescalarN width parameter?

Add more Counter -> 8bit compare blocks to make all the LEDs flash at different rates. Try setting them to 50, 49, 48, 47 and 46.

LEDs counting

Load the Examples -> LED -> counter.

This counts from 0 to 15 on the LEDs.

Decimal	Binary
0	0000
1	0001
2	0010
3	0011
4	0100
5	0101
6	0110
7	0111
8	1000
9	1001
10	1010
11	1011
12	1100
13	1101
14	1110
15	1111

Try removing the clock and using a button to increase the counter.

red VGA

Load Examples -> VGA -> red

Upload onto the board and check the display shows a red screen.

The AND gates are used so that the red, green and blue outputs are only on when the active video signal is true.

Modify the 1s and 0s to change the colour on the screen.

colour control

Instead of using the 1s and 0s to change the colours, use the 3 buttons.

Solution: Examples -> VGA -> buttons

split colours

Make the bottom half of the screen blue.

In the Bilbao collection, use the Counter -> 10bit compare block to compare the y_px output of the VGA block with a parameter.

Use the more output of the compare block to drive the AND gate of the blue signal.

Solution: Examples -> VGA -> half blue

Advanced

• use the equal output of the 10bit compare block to show lines
• use the x_px output of the VGA to do vertical splits
• use 2 10bit compare blocks to draw a cross on the screen
  • Solution: Examples -> VGA -> cross
• use other logic gates to change the colours depending on the split

Adjustable Wipe

Load Examples -> VGA -> adjustable wipe

Use buttons 1 and 3 to move the horizontal split up and down.

Try:

• change the colours on each side
• change it to a vertical wipe
• copy the counter and comparision blocks to make an adjustable vertical AND horizontal wipe.

Further Resources

• Obijuan's digital electronics tutorial - in Spanish
• Obijuan's verilog tutorial - in Spanish