Pokitto generating 640x480@60Hz VGA


#21

Wow! That is quite an achievement :slight_smile:


#22

Next step is to add a keyboard connector & BASIC. And then we’ve got ourselves a nice little home computer :wink:


#23

I’d be happier with just being able to play Pokitto games on a large monitor,
even if a hat was needed to be able to do it at a decent speed.


#24

That’s actually what I am after as well. The implementation I have done here leaves the second timer completely free. This means sound playback etc could still be done at the same time. I’m not saying this is leading to a Pokitto console but its ever so faintly pointing in that direction.

A 10€ hat that could do this would be pretty cool wouldn’t it?


#25

Maybe you are building an IchigoJam-basic brain…
Ichigo need a screen output, sound output, keyboard input and maybe a few GPIO.
They do it on custom hardware, and the Raspberry Pi.
But having a HAT connected to the Pokito to transform it into a TV Computer (like 25-30 years ago) would be great achievement.
That would be like the Switch that you can play while plugged to the screen or on the go.


#26

I was at the workshop just now, assembling Pokittos for a new order.

While I was there, I tried a new approach.

Result 220x480 @ 8 colors stable.

From a standard Pokitto, through the PEX header.

Didnt have time for pictures/video


#27

Erinomainen! Edistystä!

Doesn’t that mean that 220x240@ 16 colours should be theoretically possible?
(I’m expecting there’s a technical reason why it won’t work, involving timing or something.)


#28

The VGA signal is a funny thing because it is analog. So the way I do it now I have 3 signal lines and I mask them out. So R = 0x1, G = 0x2, B = 0x4, RG (yellow) = 0x3, RB (pink) = 0x5, GB (cyan) = 0x6, RGB (white) = 0x7.

If we want more colours, those signal lines need to be “split” into several levels of voltage between 0…0.7V by using, for example, a resistor ladder.

So then we would have 6 lines for color: R,G,B,R/2,G/2,B/2. This allows 2^6 = 64 colors.

So technically yes, at least 64 colors seems feasible relatively easily.

On the code side it is already using 8 bits for color. So that does not limit