#9 Design a Handheld POV [Post Homework Here]

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ThePyroElectro
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#9 Design a Handheld POV [Post Homework Here]

A new lesson was posted today:
http://www.pyroelectro.com/edu/fpga/handheld_pov/

Post your homework answers here to compare with everyone else!

Bingo600
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Re: #9 Design a Handheld POV [Post Homework Here]

The homework looks like the one from lesson8

/Bingo

ThePyroElectro
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Re: #9 Design a Handheld POV [Post Homework Here]

Bingo600 wrote:The homework looks like the one from lesson8

/Bingo I'll fix this + the schematic PDF (it says lesson8 as well) on sunday. Sorry Bingo600
Newbie Pyro
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Re: #9 Design a Handheld POV [Post Homework Here]

Seems like the schematic is fixed , but not the homework

/Bingo

ThePyroElectro
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Re: #9 Design a Handheld POV [Post Homework Here]

Bingo600 wrote:Seems like the schematic is fixed , but not the homework

/Bingo

They're all fixed now!

Bingo600
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Re: #9 Design a Handheld POV [Post Homework Here]

HOMEWORK QUESTION 1
Modify The ROM in lesson10’s VHDL code, so the POV message will be: HELLO!

I suppose you mean lesson9's ....

Code: Select all

type num_array is array (0 to 31) of std_logic_vector(7 downto 0);
constant led_message : num_array := (
0  => "00000000",               --
1  => "11111111",               --********
2  => "00010000",               --   *
3  => "11111111",               --********
4  => "00000000",               --
5  => "11111111",               --********
6  => "10010001",               --*  *   *
7  => "10000001",               --*      *
8  => "00000000",               --
9  => "11111111",               --********
10 => "10000000",               --*
11 => "10000010",               --*
12 => "00000000",               --
13 => "11111111",               --********
14 => "10000000",               --*
15 => "10000000",               --*
16 => "00000000",               --
17 => "11111111",               --********
18 => "10000001",               --*      *
19 => "11111111",               --********
20 => "00000000",               --
21 => "00000000",
22 => "00000000",
23 => "00000000",
24 => "00000000",
25 => "00000000",
26 => "00000000",
27 => "00000000",
28 => "00000000",
29 => "00000000",
30 => "00000000",
31 => "00000000"
);

HOMEWORK QUESTION 2
How would the LED message change, if we used a faster clock signal to the CPLD, from the
555 timer?

I haven't build the pow (blush).
But i'd suppose either :
1: The letters would be narrower , as (with the same hand movement velosity) there is less time where the leds are on.
2: The on time would be so fast so it would look like a blur of red.

HOMEWORK QUESTION 3
What is a good clock frequency to use when building a hand-held POV? Why?

200Hz (5ms) - (video says 5us ... thats a tad fast for 200Hz)

At 200Hz the flicker isn't visible to the human eye.

/Bingo

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