Shift838 Posted May 9, 2023 Share Posted May 9, 2023 (edited) So I have ordered a few different Atari ST to VGA cables and tried them on 3 different monitors that support 15kHz. I have noticed that they all seem to look like they lose pixels on the Atari desktop, namely on the text like the A Drive, etc. I do not have this issue with ST to SCART, but only to VGA. I have designed a new version that is on a breadboard right now (tested for low/med resolution - monochrome switch will be tested later this week). This will not be a cable but more of an adapter board that is housed in an enclosure. It will have a 3.5mm audio jack for some PC speakers as well. Only thing needed to connect to the ST will be a straight through DIN13 male to male cable and a standard VGA cable. Power for the IC circuity will be provided by the ST 12v pin and will regulate down to 5v. I have had to add additional circuitry to clean up the signals before it hits the VGA connector to get the display crisp and clear. I'll post pics later when I get home. Edited May 9, 2023 by Shift838 7 Quote Link to comment Share on other sites More sharing options...
+DarkLord Posted May 9, 2023 Share Posted May 9, 2023 Interesting. Can you tell us how this will differ from the already available solutions like the UBE style adapters available from the Exxos Shop and a few other Euro vendors? RGB2HDMI is much more involved but is another solution as well. I'm using one of the Exxos Shop versions with that very popular Dell 27" monitor (in a huge thread at Atari Age) and it works great. No loss at all... Thanks. Quote Link to comment Share on other sites More sharing options...
+remowilliams Posted May 9, 2023 Share Posted May 9, 2023 One thing that seems to remain unaddressed in the ST/VGA adapters is RGB signal buffering. Good Amiga adapters do this but I've not seen an ST one doing it, and it seems like the STs (and some way more than others) could use it. Quote Link to comment Share on other sites More sharing options...
TheNameOfTheGame Posted May 9, 2023 Share Posted May 9, 2023 Yes, those cheap amiga video adapters I have seen use power from the video connector for their buffering. The ST is hampered by that lack of power available on the video connector so external power from somewhere is needed. Well, STE has 12v on the connector but there aren't as much of those in use. I think that is a main reason why we haven't seen such a solution on our platform. Hope this new board buffers the signals. Would do wonders to clean up the jail bars issue . Wonder where the 12V line he mentioned is coming from? 1 Quote Link to comment Share on other sites More sharing options...
Shift838 Posted May 9, 2023 Author Share Posted May 9, 2023 i should have mentioned the 12v line is from a STe or MEGA ST. It will also have an external power plug for use if needed. It will have buffers on the digital signals. Quote Link to comment Share on other sites More sharing options...
Shift838 Posted May 9, 2023 Author Share Posted May 9, 2023 All wiring diagrams I have found for any Atari ST shows pin #8 on the DIN 13 to be 12v. Is this wrong or does all Atari ST have 12v on that pin? Quote Link to comment Share on other sites More sharing options...
TGB1718 Posted May 9, 2023 Share Posted May 9, 2023 On 520ST and STE it's 12V via a 1.2K resistor, so couldn't really power any circuits, not looked to see if it's any different on the Mega's Quote Link to comment Share on other sites More sharing options...
TheNameOfTheGame Posted May 9, 2023 Share Posted May 9, 2023 6 hours ago, Shift838 said: i should have mentioned the 12v line is from a STe or MEGA ST. It will also have an external power plug for use if needed. It will have buffers on the digital signals. Great, external power plug would be fine. Quote Link to comment Share on other sites More sharing options...
TheNameOfTheGame Posted May 9, 2023 Share Posted May 9, 2023 3 hours ago, TGB1718 said: On 520ST and STE it's 12V via a 1.2K resistor, so couldn't really power any circuits, not looked to see if it's any different on the Mega's Is it 12V on STFM? Both these pages state that it is GND for STs and 12V for STEs. https://allpinouts.org/pinouts/connectors/computer_video/atari-st-monitor/ https://info-coach.fr/atari/hardware/interfaces.php Quote Link to comment Share on other sites More sharing options...
Jfcatari Posted May 9, 2023 Share Posted May 9, 2023 7 hours ago, DarkLord said: Interesting. Can you tell us how this will differ from the already available solutions like the UBE style adapters available from the Exxos Shop and a few other Euro vendors? RGB2HDMI is much more involved but is another solution as well. I'm using one of the Exxos Shop versions with that very popular Dell 27" monitor (in a huge thread at Atari Age) and it works great. No loss at all... Thanks. I am also using one of the color/mono switchers with the Dell 27". Also an outstanding picture! Quote Link to comment Share on other sites More sharing options...
Shift838 Posted May 9, 2023 Author Share Posted May 9, 2023 7 hours ago, DarkLord said: Interesting. Can you tell us how this will differ from the already available solutions like the UBE style adapters available from the Exxos Shop and a few other Euro vendors? RGB2HDMI is much more involved but is another solution as well. I'm using one of the Exxos Shop versions with that very popular Dell 27" monitor (in a huge thread at Atari Age) and it works great. No loss at all... Thanks. The main differences will be: - buffered signals - color and monochrome modes selectable via dip switches 1 Quote Link to comment Share on other sites More sharing options...
+remowilliams Posted May 10, 2023 Share Posted May 10, 2023 I am very interested in seeing if a buffered signal device can clean up some of the mess of ST video. I kept meaning to get around to trying this myself, but never quite have : D Quote Link to comment Share on other sites More sharing options...
Shift838 Posted May 10, 2023 Author Share Posted May 10, 2023 1 hour ago, remowilliams said: I am very interested in seeing if a buffered signal device can clean up some of the mess of ST video. I kept meaning to get around to trying this myself, but never quite have : D when I get one of these types of projects stuck in my head, I focus on it until it's done. I usually have 3 to 5 I am working on at any one time. Quote Link to comment Share on other sites More sharing options...
Cyprian Posted May 10, 2023 Share Posted May 10, 2023 7 hours ago, TheNameOfTheGame said: Is it 12V on STFM? Both these pages state that it is GND for STs and 12V for STEs. https://allpinouts.org/pinouts/connectors/computer_video/atari-st-monitor/ https://info-coach.fr/atari/hardware/interfaces.php I see 12V on these 520ST and 1040STf schematics: https://archive.org/details/Atari_520ST_Schematic_1985/page/n1/mode/2up https://archive.org/details/Atari_1040STf_Schematic_1986_Atari/page/n1/mode/2up Quote Link to comment Share on other sites More sharing options...
TGB1718 Posted May 10, 2023 Share Posted May 10, 2023 9 hours ago, TheNameOfTheGame said: Is it 12V on STFM? Both these pages state that it is GND for STs and 12V for STEs. I think it would be unlikely to be different between machines, as all peripherals are expecting the same pinout connections. Just looked a the diagram and it's 12V via a resistor, same as the rest. Quote Link to comment Share on other sites More sharing options...
TheNameOfTheGame Posted May 10, 2023 Share Posted May 10, 2023 Ah that's great. Guess those pinout pages are wrong. Looked in the Atari Profibuch also and it says pin 8 is 12V at max 10mA. Is that enough current for the buffer circuit? Quote Link to comment Share on other sites More sharing options...
Shift838 Posted May 10, 2023 Author Share Posted May 10, 2023 2 hours ago, TheNameOfTheGame said: Ah that's great. Guess those pinout pages are wrong. Looked in the Atari Profibuch also and it says pin 8 is 12V at max 10mA. Is that enough current for the buffer circuit? Probably not enough current. Thanks for finding this. External power it is.. Quote Link to comment Share on other sites More sharing options...
+DarkLord Posted May 12, 2023 Share Posted May 12, 2023 On 5/9/2023 at 7:43 PM, Shift838 said: The main differences will be: - buffered signals - color and monochrome modes selectable via dip switches Buffering should help. As for selectable color and mono modes, the UBE switches also have this. Some have a slide type switch and others, like the Exxos version, require a simple momentary press to change modes. Thanks. Quote Link to comment Share on other sites More sharing options...
Shift838 Posted May 17, 2023 Author Share Posted May 17, 2023 I wanted to get my switch in before taking a photo of the breadboard. It has a buffer circuity, sync separator, external audio hookup for PC speakers of course and is switchable between monochrome and color modes. It is powered by a 5v Mini USB connection. Switching modes need to be done before powering the unit up as it will result in a hard reset of the ST if not. Will be ordering a set of prototype boards next day or so. Pics below.. LOW/MEDIUM Resolution (Color) mode: High Resolution (Monochrome) mode: 4 Quote Link to comment Share on other sites More sharing options...
Shift838 Posted May 17, 2023 Author Share Posted May 17, 2023 thinking of adding a video amplifier circuit to the RGB lines. I have one and will see if it makes any difference tomorrow. But just with the buffers on the HSYNC and VSYNC lines it looks good. Quote Link to comment Share on other sites More sharing options...
Goochman Posted May 17, 2023 Share Posted May 17, 2023 Looks nice - will this work on any VGA monitor or just those that support 15mhz or such? Quote Link to comment Share on other sites More sharing options...
Shift838 Posted May 17, 2023 Author Share Posted May 17, 2023 1 hour ago, Goochman said: Looks nice - will this work on any VGA monitor or just those that support 15mhz or such? Low/Medium color requires a 15kHz monitor as most do, monochrome will work on any VGA monitor. If you want to be able to use a ST on a standard VGA monitor then you need to go with something like the GBSControl unit that will take the 15khz signal and convert it to the standard VGA frequency. Quote Link to comment Share on other sites More sharing options...
TheNameOfTheGame Posted May 18, 2023 Share Posted May 18, 2023 Looks promising! Not a jailbar in sight :). Quote Link to comment Share on other sites More sharing options...
Chri O. Posted May 18, 2023 Share Posted May 18, 2023 On 5/17/2023 at 5:07 PM, Shift838 said: If you want to be able to use a ST on a standard VGA monitor then you need to go with something like the GBSControl unit that will take the 15khz signal and convert it to the standard VGA frequency. Or buy this Dell SE2722H 27" Full HD (1920 x 1080) 75Hz LED Monitor ------------- A new 27 inch monitor that is available and works 100%! $119.99 🙂 Quote Link to comment Share on other sites More sharing options...
Jfcatari Posted May 19, 2023 Share Posted May 19, 2023 (edited) Or here on ebay for 99 https://www.ebay.com/itm/Dell-27-1080p-Full-HD-Monitor-75Hz-4ms-AMD-FreeSync-Black-SE2722H/364190268758?_trkparms=amclksrc=ITM&aid=111001&algo=REC.SEED&ao=1&asc=20160811114145&meid=be8cfdc06afa481ca3c274868931407e&pid=100667&rk=3&rkt=8&sd=266240646433&itm=364190268758&pmt=0&noa=1&pg=2351460&brand=Dell&_trksid=p2351460.c100667.m2042&pageci=800de2cf-e950-4e9d-900f-6c83ecc30f26&epid=16048194503&redirect=mobile Edited May 19, 2023 by Jfcatari Quote Link to comment Share on other sites More sharing options...
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