GBS-8220 to Atari ST (2012 topic)

[Shredder11]

What is the model revision number of your GBS-8220 and where did you buy it from (if Ebay state seller). I have v4 that I got last year and is waiting patiently for me to find the time to set it up and use it.

[Guest]

its all very well playing with these boards
however i have one i soon found out there is about at least 5 versions of the firmware
it would be better to find out how to dump and program there firmware via the board port
i gave up and use now a VBOX it works far better and frame perfect
better to spend time to find the working firmware and flash method
just my view .... it does work fine for st but wont work on ste or mega etc across the versions ive seen
not to mention the 50/60hz issue

many people have issues with this board its cheep and nasty and not reliable even the retro pay game machines its was intended to work with
has ZERO support for the firmware online !!!
i have one someone can buy give me 20 quid for it

in my honest opinion the only way to fully correct and add a VGA SVGA port is to rework a FPGA etc chip
that replaces the shifter
duplicates its normal functions perfectly in code i can supply a callback based DLL in c++ for the shifter for reference

and at the same time provides a VGA svga port even hdmi port will and can be made to work PERFECTLY
in code... on a dil socket riser adding the fgpa to do the shifters work and provide the actual port

the librarys in c exist the chip exists the code can be made in a week

as for the ste etc with gstshifter perhaps this whole ic can also be drifted off and replaced using a similar method or some sort of piggy back

i was disappointed with its lack of features immature menus and crap online support

its in my one day box for sure!!!


for instance why even have to combine the sync when the ic just has to separate them again

kind of daft?>??
i posted a very similar comments some years ago
but as usual it falls on deaf ears when the going gets harder ...

the dil shifter is the issue !!! not this board
its not made for doing the job its was intended to do

a waist of pcb time chips and effort of others for doing something you can find a rgb monitor easily will do

[Shredder11]

I have a VBOX (cost about £1 + P&P I think!) and it works great but not with my TFT LCD monitor for some reason; it only works with my old Sony CRT monitor.

[Guest]

what problem do you get ?? out of range etc?? interesting to me
even works fine with ste i use asus 22" tft

i do also have an IBM tft and it works

i find using older square lcd is more stable
the wide screen and scaling seems an issue for all atari's well the falcon or TT is aok on wide screen
as usual the falcon comes out the best... with the TT its ok on most settings except ste modes

[Shredder11]

My TFT LCD is a 19" 5:4 CTX X962A bought in November 2005. It's 2009 since I last used the VBOX and I cannot remember what it did exactly, but I did not get any image at all so maybe it was out of range I dunno; need to dig it out and try again me thinks.

For anyone reading this thread and wondering what a VBOX is, look here (V-Box - MV-888) http://www.sasakiuk.u-net.com/vbox.htm

[1024MAK]

Hi Guys,

I recently (within last month) purchased a GBS-8220 and to my utter shock and horror, it did not work with the ST
I then spent a number of fruitless hours trying to communicate with the people at Gonbes, but alas it was not to be - they just wanted me to upgrade to the US$400 model of their board.

So I went to work with my scope and Google.

# According to the specs for the board I purchased, the GBS-8220 only supports separate H & V Sync for line rates > 31kHz.
# According to Gonbes, the board fully supports both positive and negative sync.

Both of these appear to be true:
* Regardless of polarity of H & V Sync, I could not get board to display an image (other than the odd random frame) when separate sync pulses were applied.
* Regardless of polarity, a CSYNC signal was correctly interpreted.

My solution was to use a 74HCT00 chip (Quad 2-input NAND) to create a composite sync signal. An AND gate would work just as well.

At its simplest, here is the circuit (courtesy of twobits.com, who published this a while back)
http://www.twobits.com/cga.gif

I've attached a couple of photos (you will need to scroll the images as they are taller than the previews):

#1 - 74HCT00 - the lash-up

74HCT00.jpg

I used the +5V connector from the GBS-8220 board (they even supplied a wire, wasn't that nice!)
The HSYNC and VSYNC signals are connected to pins 1 & 2 of the Quad-NAND (doesn't matter which goes where).
The CSYNC signal was pulled from pin 3 and connected to the CSYNC input on the GBS-8220 (it also seems to work when connected to the HSYNC input).
As noted in the image, I could have easily used the 5 post connector on the edge of the board (I confirmed that CSYNC applied there works fine) - but the GBS-8220 came with the white connector and wires, so that's what I used.

#2 - It lives! A shot of the GEM desktop

Alive.jpg

#3 - Oscilloscope traces showing separate input, plus composite output (inverted)

DSO-Quad.png

The Magenta trace is the incoming VSYNC signal (5V).
The Green trace is the incoming HSYNC signal (5V).
The Cyan trace is the output CSYNC signal (5V).

There are obviously a number of tidy-up items to do, like putting a ceramic cap across the power supply lines to filter noise and maybe some pull-up/down resistors on the input and output pins (including unused inputs). But I thought I'd publish these initial results, as there do indeed seem to be a lot of questions around "will the GBS-8220 board work with my ST/Amiga/<insert 80's computer here>?", and this circuit is a lot safer to the ST than capacitors 'shorting' sync pulses, and has the benefit that at its simplest the component count is 1

The above circuit worked just fine for both Low and Medium resolutions, on both a 1040 STF and a 1040 STFM.

Doug

PS: Thanks to everyone who has posted on this topic, there are a lot of good references.[/size]

Yes, mixing the H and V syncs does seem a bit point less, but that is one way to get the GBS-8200 V4.0 board to work, as I showed here.
There are indeed other ways to mix the syncs. And indeed any that do not load the Atari signals, and which produce good clean suitable syncs for the GBS-8200 V4.0 board work as well.

As to the people who are not happy with GBS-8200 V4.0 boards, well what do you want for £20?
If you want a better unit, get your wallet out, there are other much more expensive units out there for a much higher price...

Mark

[dougforpres]

Shredder11:
The GBS-8220 I got is the V3.0 from 2010.


Mark:
The only other diagrams I'd seen up until last night were the "twist the two wires together" option (with resistors/cap) and the one that used a sync-splitter on the composite video output. I hadn't actually seen anyone attempt a sync combiner until I hit send

I think it was because of the permissions of this board are such that images aren't shown unless you sign on, and phpbb is quite aggressive about expiring sessions - so of course as soon as I signed on and pressed send, hey presto, your stuff showed up (along with a couple of others I hadn't seen).

Hopefully with all of these variations on a theme out there people will feel a little more confident to fork out the $$ for a converter that really works quite well considering the price - especially if you don't want to mess with the guts of your ST.


simbo2:
I completely agree about how stupid it is to have to combine syncs so that the board can then separate them again... especially when the board actually supports separate sync inputs!
I actually have quite an email trail in my attempts to get information/assistance out of the Gonbes people. I don't know if all incoming mail is sent thru an English -> Chinese translator, but the answers I got were very vague and not very helpful. When I asked for a technical manual I was sent the standard user guide. When I asked again for "a manual a software developer might use" and asked what the function of the LED was I was pointed to the web page that allows you to download... the standard user guide. When I sent detailed information (and pictures) about video levels, pins, polarities, frequencies and asked them if they could "check with a developer" I got a "You need to buy the $400 variant".

My final correspondence with them was last night, after I got the board working with a $1 chip - I suggested that if they were to update their software to accept separate sync pulses in the 16kHz range of CGA/EGA/80's home computers then they'd probably sell a whole lot more boards. The response I just received was (punctuation intact):

hi:Doug;
Cheerfully to see the GBS8220 work well for your computer..

[Guest]

http://nootropicdesign.com/ve/downloads/LM1881.pdf

this ic is perfect for the job
using the composite sync output from the stf / ste 13pin video socket
then this ic to the board

its just a small 8 pin dil and costs buttons
and an easy thing to wire up with just a couple of components
in a topic far ago i mentioned it before
there is also an odd even output change over pin {prob not needed}
and it will remove and output a separate back porch from the sync {not needed}

this boards inputs are TTL so the output from the atari is too small
and unclean
this will fix it to work with any atari i suppose
as we know it supports the refresh

so
1} resistors in series to add the signals together is unstable because the codec on the board works over time
2} the output for an atari stf component sync is ~ 0.7v p-p
the output of an atari ste is about 1v p-p
TTL inputs on the board are 5vp-p so some level converter cleaner like the LM1881 is needed

most ataris have a modulator etc ... that provides composite sync
so only st machines with no modulator will need to add the sync together before its input to the 1881
the chip will then clean it up to separate sync again

[TheNameOfTheGame]

Hello, how do you tell what version a GBS-8220 is?

I see this one on ebay but no version listed:
http://www.ebay.com/itm/NEW-ARCADE-GAME ... 3a6ac9a0af

And then a 8200. Is this an older model of the 8220?
http://www.ebay.com/itm/Brand-NEW-ARCAD ... 3a6ac994e1

Thanks.

[Methanoid]

Hello, how do you tell what version a GBS-8220 is?

I see this one on ebay but no version listed:
http://www.ebay.com/itm/NEW-ARCADE-GAME ... 3a6ac9a0af

And then a 8200. Is this an older model of the 8220?
http://www.ebay.com/itm/Brand-NEW-ARCAD ... 3a6ac994e1

Thanks.

The auction you referred to shows a v3.0 in the picture (it is clearly visible if you look on the expanded pic) but I doubt they will be selling v3. I bought one from another supplier and got the "new" v5.0

[TheNameOfTheGame]

Now that you mention it, I looked again and was able to see in the picture where it says v3. Based on your experience I'll just have to wait to get the unit to see the version.

Earlier in the thread 1024MAK linked to some sellers with the HD9800/GBS8200 v5 boards for sale.

So there are HD9800, GBS8220 and GBS8200 versions correct? Are they all functionally equivalent with regards to hooking a ST up with them?

Hello, how do you tell what version a GBS-8220 is?

I see this one on ebay but no version listed:
http://www.ebay.com/itm/NEW-ARCADE-GAME ... 3a6ac9a0af

And then a 8200. Is this an older model of the 8220?
http://www.ebay.com/itm/Brand-NEW-ARCAD ... 3a6ac994e1

Thanks.

The auction you referred to shows a v3.0 in the picture (it is clearly visible if you look on the expanded pic) but I doubt they will be selling v3. I bought one from another supplier and got the "new" v5.0

[TheNameOfTheGame]

Hello, how do you tell what version a GBS-8220 is?

I see this one on ebay but no version listed:
http://www.ebay.com/itm/NEW-ARCADE-GAME ... 3a6ac9a0af

And then a 8200. Is this an older model of the 8220?
http://www.ebay.com/itm/Brand-NEW-ARCAD ... 3a6ac994e1

Thanks.

The auction you referred to shows a v3.0 in the picture (it is clearly visible if you look on the expanded pic) but I doubt they will be selling v3. I bought one from another supplier and got the "new" v5.0

Well, I received a v3 from them. The seller was chowhe_taiwan. I sent some emails around seeing if anyone else had a v4 (most of the pictures on the ebay listings show a stock v3 image). I received an interesting response from one seller:

*edit* chowhe_taiwan says they made a lot of v3 pcbs so they still show the v3 stenciled, but the software is v4...

[Guest]

i will try to find the flash rom details and its programmer
then figure out how to dump the software
... if indeed the board didnt change as it seems then the firmware should be both easy to recover
and from what i remember of the port details easy to flash over rs232 3 wire

the two ports are marked

P5 ==
1:SDA = serial data
2:VCC = 5v? 3.3v
3:GND = 0V
4:SCL = serial clock

{standard two wire coms}

P6 ==?
1:VCC = 5v? 3.3v
2:TXD = transmit data out
3:RXD = receive data in
4:GND = 0V

{standard 3 wire rs232}

i think one port will be used for the firmware on the main codec
and the other for the custom ic next to the port
tracing back some of the tracks i see this is the case

so there is two parts to the flash block the codec and the custom plcc chip marked
GONBES
GBS800MV
http://www.atari.org.pl/forum/viewtopic.php?id=7094&p=8

here is some polish talk about it

[delvis]

Seeing this Youtube link it looks easy to make this work. Is it really a lot harder?

http://www.youtube.com/watch?v=Kjseux-qJeQ

[Hippy Dave]

Code: Select all

The youtube video instructs you to make a SHORT CIRCUIT.
(This is BAD ... ok?)

vsync >--o
         | <--- (bad short circuit here)
hsync >--o-----> composite sync

************************************************************
If the following circuit doesn't work with the GBS-8220,
build a sync-combiner with an XOR gate. (see previous posts)

               1N4148 or schottky diode
            o----|<----o
            |          |
vsync >-----o---/\/\---o
                3.3k   |
                       |
                3.3k   |
hsync >-----o---/\/\---o----/\/\----> composite sync
            |          |    330
            o----|<----o
               1N4148 or schottky diode

[Strider]

Hi there,

I've tried my brand new HD9800 V5.0 yesterday.
On another topic there is a Video Sync Mixer (http://www.atari-forum.com/viewtopic.ph ... 00#p203262).
Is it really useful? When I connected my 1040 STF and 520 STE to the HD9800, it worked like a charm, without any mixer (I bought a 74LS86 for nothing )

I've also tried an Amiga 500 and an Amstrad CPC 6128. And also 3 different LCD TVs. I must admit it works quite well for the price (about 20 € postage paid).

By the way, I bought the HD9800 on Ebay (reseller is chinatobby2011).

[delvis]

Any special way to wire it up? Diagram of how you hooked yours up?

[Strider]

Any special way to wire it up? Diagram of how you hooked yours up?

No special way to wire it up, it is very easy:

Code: Select all

Signal        HD9800 wire colour        SCART pin
RED           Red                       15
GREEN         Green                     11
BLUE          Blue                      7
SCYNC         Gray                      20
GND           Black                     21-17-13-9-5

I made more tests yesterday with my 1040 STE and my 24" LCD monitor, running some demos.
Colours are great.
Horizontal scrollers aren't very smooth, however I wonder if it's due to the different framerate between the ST and the monitor. But I must admit the result is not so bad.
Still, I was a bit disappointed by interferences (random white dots on screen). It's probably due to the video converter. But I also noticed there are less interferences when I move the HD9800 away from the LCD and the ST.
I'll try to make some photos and videos ASAP.

edit : after more tests, the interferences almost disappeared when I switched the output resolution to 640x480. I have to set the vertical size to 40 in the geometry menu to see the lower border of the ST screen.

[delvis]

Strider - I ordered the newest one from the vendor you listed. HD9800.

[delvis]

Got mine today. Tried it with the cable from "Best". As before the VGA Hi res worked but seemed to freeze. The Low and Med Res was there and clear but just kept rolling on the screen.

[calimero]

All this chines 15KHz to VGA converters are crap.
I have 8220 and I saw few similar and all are more or less same.

It is order of magnitude better to find LCD that can display 15KHz signal directly from Atari.

[DarkLord]

Which unfortunately, is almost impossible to do.

[calimero]

Which unfortunately, is almost impossible to do.

It's not!

E.g. Dell u2410 works great with Atari signals.
My Dell u2412m also works with Falcon standard RGB resolutions but wont display exotic one take a look at: http://www.youtube.com/watch?v=Vloo7nwL56U

I am pretty sure that there are more new monitors that will display 15KHz image! (although you will not find in technical specification this data!!!)

[delvis]

Thanks for info on here. I got it working.

Not using the VGA cable I bought from Best, I built a test cable with a 13 pin to the HD9800 board connector. After playing with the 9 and 12 pin connectors and getting rolling screen I took the 9 wire and connected to the 2 Pin and it worked correctly.

Atari signal wire color HD9800 /GBS-8200 V5.0 board
13 pin DIN P11 connector
6 ------green video---green wire------------"G"
7 ------red video-----red wire--------------"R"
2 ------CSync --------grey wire-------------"S"
10 ------blue video----blue wire-------------"B"
12 ------VSync---------yellow wire-----------"VS"
13 ------Ground--------black wire------------"GND"

This is it and it works perfect. (Except for the normal complaints of shadowing, ect.)

Settings on HD9800 at default, using RGBS at 1024 x 768 in the Menu. I tried this without hooking the yellow wire up and had distortion along the bottom of the screen. Hooking up the yellow and it went away. Tried going to different resolution in the HD9800 menu and it started have static along bottom of screen. So basically this did not require adding anything else. Built cable and wired directly to HD9800 connector.
I will use the BEST VGA cable for my High res Monochrome. I will use this one for my Low and Medium res.

[DarkLord]

This is it and it works perfect. (Except for the normal complaints of shadowing, ect.)

Hi Delvis. What "normal" complaints of shadowing are you referring to? Is it where
the text seems to drop out in certain places?

If so, there were some solutions that might help given in a few other related threads.

Seems that some devices put out too "hot" a signal (for want of a better description)
and you can apparently put resistors on the R, G, and B lines to help. I'm thinking it
varies a bit with each particular piece of hardware but 120-150k seem to spring to
mind, IIRC.

HTHs.