ST video/mouse/audio switch

[Shift838]

I have quite a bit of experience designing KVM switches and have done it for standard PCs and a couple of retro PCs like the Myarc Geneve 9640, which is RGB.

 

gauging interest to design one for the Atari ST.

[TGB1718]

Just a thought, what about USB mouse, they are the most common these days

[Shift838]

5 hours ago, TGB1718 said:

Just a thought, what about USB mouse, they are the most common these days

that is definitely possible, i just need to locate some open source for USB to ST mouse or come up with one of my own.

 

one of my original thoughts was to offer the standard ST connections like the DB9 for the mouse, etc so that just straight through cables could be used to hook up the switch to the ST computers.  Then if the user wants say a PS2 or USB mouse they could use the adapter to plug onto the mouse port that the actual mouse would hook up to.  When the button is pressed for the specific computer then it will activate for that computer only.

Edited May 10, 2023 by Shift838

[Shift838]

I have been working on the design of this switch.  So far I have the brain as an Arduino Nano to control up to 4 ST computers with audio and standard mouse.  I figure that the user can plug their own mouse adapter into the main port for use with a USB or PS2 mouse.  Makes things much simpler.

 

Output for both SCART and VGA (15kHz only).  

 

Using a sync separator circuit to clean up vidoe as well as a buffer circuit to buffer both HSYNC and CSYNC lines.

 

Question for all you guys..  

 

I need to add a switch to be able to toggle between LOW/MED color and HIGH Monochrome.

 

Would you like to see 4 separate switches to control each one so each ST can be configured with their own respective resolution, or would you like one switch to be shared between them all so if you want LOW/MED color you leave it off and get it on all the ST's connected and when engaged all are set to HIGH Monochrome?

 

I can do either, but of course added more switches increases the price and the code complexity a bit

 

 

[Shift838]

I think I'll be upgrading to a Raspberry Pi Pico controller as they are a bit more powerful than the Arduino Nano and offer a few more pins to allow for easier programming.  I actually need 2 more pins than the Nano has to be able to control a 4 port switch to be able to buffer and route the color and monochrome video signals, mouse signals, audio signals a switch and either 4 LED's or a OLED to display what channel you are on.

 

 

[Atari8guy]

On 5/29/2023 at 8:12 PM, Shift838 said:

I have been working on the design of this switch.  So far I have the brain as an Arduino Nano to control up to 4 ST computers with audio and standard mouse.  I figure that the user can plug their own mouse adapter into the main port for use with a USB or PS2 mouse.  Makes things much simpler.

 

Output for both SCART and VGA (15kHz only).  

 

Using a sync separator circuit to clean up vidoe as well as a buffer circuit to buffer both HSYNC and CSYNC lines.

 

Question for all you guys..  

 

I need to add a switch to be able to toggle between LOW/MED color and HIGH Monochrome.

 

Would you like to see 4 separate switches to control each one so each ST can be configured with their own respective resolution, or would you like one switch to be shared between them all so if you want LOW/MED color you leave it off and get it on all the ST's connected and when engaged all are set to HIGH Monochrome?

 

I can do either, but of course added more switches increases the price and the code complexity a bit

 

 

The independent switches would be better I think and not potentially force an accidental reset of a connected ST?

[Shift838]

3 hours ago, Atari8guy said:

The independent switches would be better I think and not potentially force an accidental reset of a connected ST?

 

Exactly what I was thinking.  Already been working on the implementation.  Hoping to have the routing done tonight..

[Shift838]

I have finished drawing out the prototype see specs below and attached image of rendering.  This is only a top render image.  There are components on the bottom side of the board as well.

 

Prototype boards have been ordered.

 

Features:

 

ST Video/Mouse/Audio 4 port switch - control up to 4 Atari ST's with one 15kHz monitor, external/internal audio and mouse support.

 

 

• Powered by a Raspberry Pi Pico
• Support for both Low/Medium color resolution and Monochrome High Resolution
  • Monochrome is controlled by a separate latching push button switch for each connected Atari ST
• Display output for both SCART and VGA
• Selectable by dip switch to:
  • Supply 2v power to SCART monitor to put monitor into RGB mode if needed (can be enabled or disabled)
  • Support for internal or external speakers for SCART (can be enabled or disabled)
    • External only for VGA output
• Audio Trimmer to fine tune audio signal if needed
• Uses Sync Cleaner to further sharpen sync signals
• Buffered HSYNC and VSYNC lines
• Selectable Drain Mode for (+5v or GND) HSYNC/VSYNC Buffer - I have seen monitors look better on Ground or +5v drain mode.
• OLED for displaying channel
• MiniUSB 5v power plug
• Firmware easily updatable
• Single momentary tactile switch will be used to cycle through inputs 1 through 4.
  • If a Monochrome switch is detected on the input as enabled, then the resolution will be set accordingly.

 

Edited June 2, 2023 by Shift838

[Coxsider]

I'm looking for a KVM switch to allow control of an ST and several PC's running Linux.

 

Is such a thing possible?

[Jfcatari]

On 6/2/2023 at 2:10 AM, Shift838 said:

I have finished drawing out the prototype see specs below and attached image of rendering.  This is only a top render image.  There are components on the bottom side of the board as well.

 

Prototype boards have been ordered.

 

Features:

 

ST Video/Mouse/Audio 4 port switch - control up to 4 Atari ST's with one 15kHz monitor, external/internal audio and mouse support.

 

 

• Powered by a Raspberry Pi Pico
• Support for both Low/Medium color resolution and Monochrome High Resolution
  • Monochrome is controlled by a separate latching push button switch for each connected Atari ST
• Display output for both SCART and VGA
• Selectable by dip switch to:
  • Supply 2v power to SCART monitor to put monitor into RGB mode if needed (can be enabled or disabled)
  • Support for internal or external speakers for SCART (can be enabled or disabled)
    • External only for VGA output
• Audio Trimmer to fine tune audio signal if needed
• Uses Sync Cleaner to further sharpen sync signals
• Buffered HSYNC and VSYNC lines
• Selectable Drain Mode for (+5v or GND) HSYNC/VSYNC Buffer - I have seen monitors look better on Ground or +5v drain mode.
• OLED for displaying channel
• MiniUSB 5v power plug
• Firmware easily updatable
• Single momentary tactile switch will be used to cycle through inputs 1 through 4.
  • If a Monochrome switch is detected on the input as enabled, then the resolution will be set accordingly.

 

Nice design and I like the use of the Pico pi.   I would be interested in such a board.