Crappy VGA image quality.

Bryce · 13:20, 21 July 15

Thanks, yes, I was about to ask why you chose the ATtiny861. I assume it was a case of "because I have one"?

Does it really need 8K ROM?? Is that just because it was done in C ? Surely it could be done in assembler in under 1K?

Bryce.

Edit: Just checked - from a price point it doesn't really matter which AT I choose, but I'd rather only have 8 pins to solder instead of 20!

CraigsBar · 13:49, 21 July 15

He he he, place your orders for a Bryce VGA adaptor fixer

||C|-|E|| · 14:37, 21 July 15

If the adaptor could apply the changes automatically it would be really great as well, although I think that it would be necessary to keep a keyboard input at hand because configuration may need tweaking. Or, at least in my case, the pre-defined modes needed modifications to run properly with the CPC (the image was completely shifted to the left). I do not really know if this is CPC related, GBS related or screen related, but the possibility of switching "on the fly" and apply the changes in real time was really useful.

Bryce · 15:40, 21 July 15

I'll have to wait until I have a working prototype to know that. There are several possibilities to tweak the settings, but I'd prefer a "plug and forget it's there" solution. As far as I can see from the data that Bruce uploaded, the device does everything automatically on boot-up without user input. The switch is only to choose between a 50hz tweak and a 60hz tweak which most likely has to happen before you power it up. The less it needs, the lower the price.

Bryce.

||C|-|E|| · 16:26, 21 July 15

Let´s see what happens then

Today I was given a cheap VGA to HDMI converters and I am curious to see what happens if I try it with the VGA output from the GBS. The main chip of the converter is this one:

http://www.macrosilicon.com/info.asp?base_id=2&third_id=3

I wonder, although maybe this is completely stupid, if it will be able to clean the signal. If it applies some sort of noise reduction it could work well when the colors are so bright and flat. Anyway, it was for free so I have nothing to lose trying it

Bryce · 21:48, 21 July 15

If it's sole purpose is to convert VGA to HDMI then I doubt it has any noise reduction built in. You don't expect a VGA signal to have much if any noise on the signal.

Bryce.

||C|-|E|| · 22:02, 21 July 15

The thing is that I actually do not how it does the conversion. I know that the chip is popular converting the image from consoles like the Wii or the PS2, but I do not know what it does. I guess that I will just try and see what happens

. HDMI audio output could be interesting, though.

Bryce · 22:14, 21 July 15

According to the Datasheet of the MS9282, it's just a straight ADC which outputs HDMI, it doesn't even do scaling, so I doubt there's much in they way of noise reduction circuitry in it.

Bryce.

||C|-|E|| · 23:02, 21 July 15

Indeed... I am testing it just now and it looks exactly the same. Good news is that it does not decrease the image quality at all (at least in a degree I can appreciate) so it could still be interesting as an option to have HDMI with audio output

. Anyway, this is starting to be messy as hell

, I really need to consider to make and enclosure or something.

[attachimg=1]

Bryce · 23:13, 21 July 15

Why don't you just get a SCART to HDMI converter then and save yourself a module?

Bryce.

||C|-|E|| · 23:16, 21 July 15

That is actually true... well, what I am going to do is to remove the HDMI converter because, as you say, it is an extra module and it does not improve the things. It was something I just wanted to try because I was given it for free and I was curious

.

Bruce Abbott · 01:25, 22 July 15

Quote from: Bryce on 13:20, 21 July 15
Thanks, yes, I was about to ask why you chose the ATtiny861. I assume it was a case of "because I have one"?

Correct.

QuoteDoes it really need 8K ROM??

Unfortunately yes. The configuration data takes up 6726 bytes (3654 bytes for startArray, plus 1536 bytes for each resolution array). The rest of the code takes up less than 200 bytes.

QuoteSurely it could be done in assembler in under 1K?

No way - sorry!

QuoteI'd rather only have 8 pins to solder instead of 20!

An ATtiny85 should do it.

Bryce · 08:16, 22 July 15

Oh, so it would. Maybe I'll make an SMD version with an ATtiny85

That should keep things extremely small. I'll probably keep the switch and LED though.

Bryce.

CraigsBar · 08:35, 22 July 15

Quote from: Bryce on 08:16, 22 July 15
Oh, so it would. Maybe I'll make an SMD version with an ATtiny85 That should keep things extremely small. I'll probably keep the switch and LED though.

Bryce.

Please do. I'll have one!

Bryce · 10:04, 22 July 15

Just messing about here. Done in SMD using an ATTiny85 it would be about 15mm x 20mm even if I keep the ISP header, switch and LED. The switch is made with solder bridge pads as many people will never need to use this. A switch could be soldered to the pads if needed. Removing the ISP/switch and header brings it down to 10mm x 15mm.

Bryce.

||C|-|E|| · 10:06, 22 July 15

Wow, that is really tiny. Would it be possible to implement the switch as a jumper?

Bryce · 10:07, 22 July 15

Yeah, a jumper wouldn't be a problem.

Bryce.

Edit: With simple jumper and further size reduction (in case the first one was too big

)

||C|-|E|| · 10:16, 22 July 15

That is great!

Bryce · 10:22, 22 July 15

I don't have any ATTiny85s here, but I'll order a few and mess about a bit with this when I have a chance.

And before anyone asks, they would cost around €15 + postage.

Bryce.

Bryce · 20:14, 25 July 15

It's not going to win any prizes for beauty. It's quick and dirty, but enough to push some I²C commands into the GBS and play with the Firmware

Bryce.

||C|-|E|| · 20:25, 25 July 15

Really cool and small! And it has the charm of the hand-made circuits

. It is funny that you are posting the picture today because I was just tiding my setup a bit this evening. Now it only needs a single power supply and it is much smaller but still, it cannot be compared with your tiny board!

[attachimg=1]

Bryce · 20:30, 25 July 15

Glad you like it. I haven't got a switch on it yet. I need to tweak the C Code anyway for the different IC, so I will disable the switch routine for now while I'm at it. On the final version I think I'll add a disable jumper too in case there's situations where you'd want it completely disabled?

Bryce.

||C|-|E|| · 20:33, 25 July 15

It could be a good idea! for the final user the jumpers are always an easy way of tweaking the boards without hassle and never bothers to have them around

pelrun · 10:36, 26 July 15

Wow, what is that plastic mounting plate setup you're using there? I think I need to design/print something similar for mounting random things together...

||C|-|E|| · 11:45, 26 July 15

Quote from: pelrun on 10:36, 26 July 15
Wow, what is that plastic mounting plate setup you're using there? I think I need to design/print something similar for mounting random things together...

Those plastics are used a lot for designing and prototyping robots and some other things. They allow you to put the sensors in different positions and try different configurations before the final robot is assembled

. I have a big bunch of them because they also allow to put PCBs together, as you can see. Then, you only need to find an enclosure for the whole monster and you are done

.

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Crappy VGA image quality.