LEGO Interface A (9750/9771) – LEGO Technic Control 1 (TC1) reference/ideas thread

[Toastie]

Hmmm - I did some more reading ...

It could be, that an MSX computer may do I/O via the joystick ports. According to this website, the PSG (programmable sound chip) is connected to these ports, and they can be accessed bidirectionally:

https://map.grauw.nl/resources/msx_io_ports.php#psgioports

That is becoming a bit tough now, because without such a machine at hand it is all pure speculation. However, this could be the way to go ...

LPRINT should of course work as well (for outputs), so the sensor data could simply go into the joystick ports. That should work as well.

Best
Thorsten

Edited Sunday at 02:59 PM by Toastie

[Toastie]

@evank I asked Gemini, how to use the joystick ports for I/O on an MSX computer - specifically configured as 2 digital inputs and 6 digital outputs. 

The MSX BASIC commands for reading/writing these ports are STICK for input and SOUND for output. I bet that both are also replaceable with IN/OUT, but then you'd need the I/O address, which are to be found as well in the webs.

But to me, it looks like the approach Gemini is proposing is matching with what I read. The BASIC code seems to be absolutely OK as well. You could try parts of it out first (e.g., just reading two inputs with STICK) and then separately test the outputs with SOUND 15, value. 

I believe this should work for you!

Best
Thorsten

Here is Gemini's answer including code:

To read 2 digital inputs and output 6 digital signals using the MSX General Purpose I/O ports, you must use both Joystick Port 1 and Joystick Port 2 simultaneously.

A single MSX joystick port only has 3 pins capable of output (Pins 6, 7, and 8) and 5 pins designated as inputs (Pins 1, 2, 3, 4, and 6/7 when read). Therefore, a single port cannot provide 6 outputs. By combining both ports, you gain access to 6 output lines and more than enough input lines.

---

Hardware Wiring Configuration

To achieve your exact configuration, wire your external digital lines to the two DE-9 ports according to the map below.

📤 Output Lines (6 Signals)

The MSX outputs signals by software-controlling Pins 6, 7, and 8 on both ports via the Programmable Sound Generator (PSG) chip.

• Output 1: Port 1 - Pin 6 (Trigger A)
• Output 2: Port 1 - Pin 7 (Trigger B)
• Output 3: Port 1 - Pin 8 (Strobe)
• Output 4: Port 2 - Pin 6 (Trigger A)
• Output 5: Port 2 - Pin 7 (Trigger B)
• Output 6: Port 2 - Pin 8 (Strobe)

📥 Input Lines (2 Signals)

Connect your external switches or digital sensors to the standard directional pins of Port 1. The MSX reads these inputs by checking if the pin is pulled to Ground (Pin 9).

• Input 1: Port 1 - Pin 1 (Up)
• Input 2: Port 1 - Pin 2 (Down)
• Note: Always connect the Ground of your external circuit to Pin 9 on both ports. [1]

---

How the MSX Controls the Pins (The PSG Registers)

The joystick ports are managed by Register 15 (Reg 15) and Register 14 (Reg 14) of the AY-3-8910 PSG chip.

1. Register 15 (Output Configuration): Controls the state of Pins 6, 7, and 8.
2. Register 14 (Input Reading): Reads the status of Pins 1, 2, 3, and 4.

Register 15 Bitmask Table

To write to the outputs, you must send a specific byte to PSG Register 15. The bits change the state of the pins as follows:

Bit	Function	Logic State
Bit 7	Select Port 2 (Set to 1 to read Port 2 inputs, leave at 1)	Always 1
Bit 6	Port 2 - Pin 7 (Output 5)	1 = High (5V) / 0 = Low (0V)
Bit 5	Port 2 - Pin 6 (Output 4)	1 = High (5V) / 0 = Low (0V)
Bit 4	Port 1 - Pin 7 (Output 2)	1 = High (5V) / 0 = Low (0V)
Bit 3	Port 1 - Pin 6 (Output 1)	1 = High (5V) / 0 = Low (0V)
Bit 2	Port 2 - Pin 8 (Output 6)	1 = High (5V) / 0 = Low (0V)
Bit 1	Port 1 - Pin 8 (Output 3)	1 = High (5V) / 0 = Low (0V)
Bit 0	Unused / Keep 0	Always 0

---

MSX-BASIC Implementation Code

You can test and run this hardware setup directly using MSX-BASIC by utilizing the SOUND command, which directly writes to the PSG registers.

10 ' --- MSX 6-OUTPUT / 2-INPUT CONTROLLER ---
20 ' Initialize Outputs: Set all 6 outputs to LOW (0V)
30 ' Binary: 10000000 (Bit 7 is 1, Bits 1-6 are 0) -> Decimal 128
40 SOUND 15, 128
50 '
60 ' --- MAIN LOOP ---
70 ' Step 1: Read the 2 Inputs from Port 1
80 ' STICK(1) returns 1 if UP (Pin 1) is triggered, 5 if DOWN (Pin 2) is triggered
90 IN1 = 0 : IN2 = 0
100 IF STICK(1) = 1 THEN IN1 = 1
110 IF STICK(1) = 5 THEN IN2 = 1
120 '
130 ' Step 2: Determine your desired output states based on inputs
140 ' Example logic: If Input 1 is active, turn on Outputs 1, 2, and 3.
150 ' If Input 2 is active, turn on Outputs 4, 5, and 6.
160 OUTVAL = 128 ' Base value (Bit 7 always 1)
170 IF IN1 = 1 THEN OUTVAL = OUTVAL + 8 + 16 + 2   ' Adds Bits 3, 4, 1 (Outputs 1,2,3)
180 IF IN2 = 1 THEN OUTVAL = OUTVAL + 32 + 64 + 4  ' Adds Bits 5, 6, 2 (Outputs 4,5,6)
190 '
200 ' Step 3: Write to the Outputs
210 SOUND 15, OUTVAL
220 '
230 ' Print status to screen and loop
240 PRINT "Inputs:"; IN1; IN2; " | Output Byte Sent:"; OUTVAL
250 FOR T=1 TO 50: NEXT T ' Short delay to prevent screen flicker
260 GOTO 60

[evank]

Sounds good! OUT and INP are how it's done in QBASIC, if I recall correctly. Lol I'd have to go check my own website.

I will definitely try the joystick port method, but probably not until another couple of weeks because right now I'm rushing to get some code working (on my trust Apple //e) in time for Brickfair next month.

[evank]

Hey I've got an idea. If each of the built-in joystick ports has two inputs, then -- if your model doesn't require more than three outputs on the same memory address -- you could have each joystick port control a separate Interface A. Thus this little MSX computer can control two of them! Somewhat. :)

[Toastie]

12 minutes ago, evank said:

Thus this little MSX computer can control two of them! Somewhat. :)

Yeah, that sounds doable! 

(you mean on the same I/O address ;) 

Best
Thorsten

Edited Sunday at 03:31 PM by Toastie

[evank]

What would you do for the power and ground? (Edit: nevermind, I see those in the pinout now.)

Edited Sunday at 03:36 PM by evank

[evank]

Hmm ... What other machines might work through their joystick ports, when there's no parallel or user port?

Apple //c? Etc....

[Toastie]

Well, it depends, I guess.

If you want access to these ports through BASIC, then BASIC commands for such actions need to be available. On the machine code level, these ports should work. On the other hand: What are outputs good for on a vintage joystick? I never played any games ... 

I just checked GFA BASIC for the Atari ST as well as TI99 BASIC: They all have built in joystick detection commands. As the MSX BASIC has as well. I believe it depends on the hardware component associated with these ports. In case of the MSX it is mostly the same as in the Atari ST (these Yamaha YM-2149 variants = sound chips w/ 2 8 bit I/O ports). So yes, in essence if there are joystick ports, and if they are connected to an I/O chip, they are more or less general purpose ports, when they are programmable. As all I am aware of are. 

Best
Thorsten

Edited Sunday at 05:06 PM by Toastie

[amine]

2 hours ago, Toastie said:

Well, it depends, I guess.

If you want access to these ports through BASIC, then BASIC commands for such actions need to be available. On the machine code level, these ports should work. On the other hand: What are outputs good for on a vintage joystick? I never played any games ... 

I just checked GFA BASIC for the Atari ST as well as TI99 BASIC: They all have built in joystick detection commands. As the MSX BASIC has as well. I believe it depends on the hardware component associated with these ports. In case of the MSX it is mostly the same as in the Atari ST (these Yamaha YM-2149 variants = sound chips w/ 2 8 bit I/O ports). So yes, in essence if there are joystick ports, and if they are connected to an I/O chip, they are more or less general purpose ports, when they are programmable. As all I am aware of are. 

Best
Thorsten

From Line  200 in Japanese hiragana is written :Migi Right, Hidari Left, Mae front, Ushiro back. 

I almost forgot about that program that use the printer port to move a lego buggy on MSX !!!

https://download.file-hunter.com/Magazines/JP/MSX Magazine/MSX Magazine (1987-10).pdf

 

Can you find out  the centronic adress on that one ?  is it &H91 ?

 

This might be the printer cable pins configuration.

Edited Sunday at 07:24 PM by amine

[Toastie]

1 hour ago, amine said:

You can find out  the centronic adress on that one ? 

I knew it - the PSG/I/O chip is addressed in the I/O port space of the Z80 

Yes - this is almost it! The hex (port) address of the I/O port is 0x91 (= dec 145) - and then just bit banging:

OUT 145,0 = all off
OUT 145,1 = output 0 ON
OUT 145,2 = output 1 ON, all others off - the usual stuff :D

The LPRINT command does more or less the same, when you found the right character for the 8-bit pattern, that is what Hans (aka Max ) demonstrated with their interface (8x out)

The one remaining thing is now inputs. I know that that Yamaha chip can do both, input and output, as it has direction registers. And these are programmable: 8 bits for 8 channels; either 0 for out and 1 for in or the other way around. Same for Atari/GFA BASIC. All we need now is the I/O port of that register, which should be around 145 as well, depending on the address decoding of course. Would this be a ZX81 it could be everywhere .

This is what Gemini tells me:

The most notable Yamaha PSG (Programmable Sound Generator) is the YM2149, a highly precise, pin-compatible hardware clone of the classic General Instrument AY-3-8910. Featuring three square-wave tone channels, a noise generator, and 16 volume levels, it was widely used in 1980s and 90s computers like the Atari ST and MSX.

The Yamaha YM2149 Core Features:

• Channels: 3 tone channels (A, B, C) capable of square-wave generation.
• Noise: 1 dedicated white-noise channel.
• Envelope Generator: Hardware-driven amplitude envelopes for complex fading and articulation.
• I/O Ports: Built-in 8-bit parallel I/O ports for controllers, keyboards, or joysticks (often utilized as paddle/joystick inputs on the Atari ST)

 @evank now you have two alternatives for testing: Using the Centronics port or the joystick ports. They are both hooked up to the PSG chip. Advantage of the joystick port: We know, how it can input data. Disadvantage: We need both joystick ports. Advantage of the Centronics port: Only one port; disadvantage: Currently not known how to read data, or better set the direction register.

@amine: Is there any hint in the document you are showing in your last post about reading inputs? I guess they did not use an Interface A to connect to the buggy or did they???  

Cool.

EDIT: I asked Gemini about the direction registers of the PSG; here is the answer. I take back a couple of things I said about AI:

To program the direction of the PSG (Programmable Sound Generator) I/O ports on an MSX computer, you must manipulate bits 6 and 7 of Register 7 (Mixer). These bits control whether the PSG's general-purpose I/O ports (Port A and Port B) are configured for input or output. [1, 2]

Critical Warnings

Hardware Damage: Never write to Register 7 without ensuring Bit 7 is set to 1 and Bit 6 is set to 0. Failing to preserve these bits can damage older MSX computers when devices are plugged into the joystick ports.

Preserve State: When changing bits in the PSG registers, always read the current register value, alter only the necessary bits, and write the new value back.

Register 7 (Mixer) Bit Mapping

Bit 6: I/O Port B (Direction: 1 = Output, 0 = Input). On an MSX, this is hardcoded as an Output (Bit 6 should always be 0).

Bit 7: I/O Port A (Direction: 1 = Output, 0 = Input). For standard MSX joystick input, this must be set to 1.

MSX Port I/O

The MSX communicates with the AY-3-8910 PSG chip using three specific I/O ports:

Port &HA0: Select PSG Register (write-only).

Port &HA1: Write Data to the selected register (write-only).

Port &HA2: Read Data from the selected register (read-only). [1]

Example: MSX-BASIC Implementation

You can safely set the PSG directions in MSX-BASIC using the built-in SOUND command, which automatically handles the safety bits internally.

SOUND 7, 128

Note: This sets Register 7 to 10000000 in binary, making Port A an input and Port B an output, while enabling sound across all channels.

Best
Thorsten

 

Edited Sunday at 07:42 PM by Toastie

[amine]

12 minutes ago, Toastie said:

@amine: Is there any hint in the document you are showing in your last post about reading inputs? I guess they did not use an Interface A to connect to the buggy or did they???  

 

They made their own custom interface card.

Edited Sunday at 07:42 PM by amine

[Toastie]

5 minutes ago, amine said:

They made their own custom interface card.

And this card does only outputs, correct?

Well Gemini knows how to configure the PSG. If only I had an MSX computer :D

Best
Thorsten

[amine]

48 minutes ago, Toastie said:

And this card does only outputs, correct?

Well Gemini knows how to configure the PSG. If only I had an MSX computer :D

Best
Thorsten

I think It was only intended for "RC" manual control. With a joystick it is still a lot of fun 😁 

Now I  think I need to find a Msx too !! 😆 

 

 

Edited Sunday at 08:33 PM by amine

[Toastie]

3 minutes ago, amine said:

It was only intended for "RC" manual control .

OK, as anticipated - same thing in Max/Hans book. It is not straight forward to get the MSX to read data from the I/O ports (Centronics/joystick). But it is absolutely doable.

But it MUST be really motivating for @evank to do exactly that!!!

BTW: I doubt that TLG ever endorsed LEGO Interface A for usage with "MSX" computers? Reasoning: There is no MSX computer, there are MSX computers 1, 2 , 2+ with different HW configs. The MSX standardization may have promoted the endorsement, but reading about all the caveats and obstacles ... well who knows.

This is all very exciting!

Best
Thorsten

   

 

[Toastie]

@evank, @amine, @alexGS,

Gentlemen, @Bliss has patched the French version of LEGO LINES he found in the Archives () to work in serial mode. He made a version that runs happily within DOSBox-X, which then communicates through Bluetooth to an ESP32 microcontroller directly plugged into Interface A!!!

Here is how to patch LINES (we should maybe put patched version onto the Archives as well? Or is your TCLogo_S version, Alex, located somewhere else? I lost track what is where):

This is how it looks like, when you have the ESP32 board attached to Interface A (<link to full post in Yves thread):

The board costs about €/$6, all that is needed is soldering a 2x10 socket to the row of GPIO pins. The red/white wires are optional; inside Int.A, I have wired +9V and (IntA)GND to pins 2 and 4 of the 20 pin port. I do that on all my 9750's as I like to power (wireless) "stuff" from there.

This means that we can now run any patched DOS version of legacy programs within DOSBox-X and have them communicate (really fast) with Interface A. This includes QBasic, Pascal, C ... programs. But even better: Without changing >anything< hardware-wise, we can use LEGO Blockly.

All this fun is running wirelessly over BT, which is appearing simply as "just another COM port" in device manager, to be declared in DOSBox-X, and you are ready to go. Same in LEGO Blockly upon connecting to (any) Interface A, just click on the corresponding COM port. Yves did a phantastic job upon achieving all this!

The best part is: You can have many Interface A attached to LEGO Blockly - or 4 in DOSBox-X using the 4 standard ISA addresses. DOSBox-X can handle even more, but that is a bit more tricky, I believe. Maybe not.    

Here is to Yves 
Best
Thorsten

P.S.: If you want me to, I can try to sketch briefly how to get this going.

[amine]

3 hours ago, Toastie said:

@evank, @amine, @alexGS,

Gentlemen, @Bliss has patched the French version of LEGO LINES he found in the Archives () to work in serial mode. He made a version that runs happily within DOSBox-X, which then communicates through Bluetooth to an ESP32 microcontroller directly plugged into Interface A!!!

Here is how to patch LINES (we should maybe put patched version onto the Archives as well? Or is your TCLogo_S version, Alex, located somewhere else? I lost track what is where):

This is how it looks like, when you have the ESP32 board attached to Interface A (<link to full post in Yves thread):

The board costs about €/$6, all that is needed is soldering a 2x10 socket to the row of GPIO pins. The red/white wires are optional; inside Int.A, I have wired +9V and (IntA)GND to pins 2 and 4 of the 20 pin port. I do that on all my 9750's as I like to power (wireless) "stuff" from there.

This means that we can now run any patched DOS version of legacy programs within DOSBox-X and have them communicate (really fast) with Interface A. This includes QBasic, Pascal, C ... programs. But even better: Without changing >anything< hardware-wise, we can use LEGO Blockly.

All this fun is running wirelessly over BT, which is appearing simply as "just another COM port" in device manager, to be declared in DOSBox-X, and you are ready to go. Same in LEGO Blockly upon connecting to (any) Interface A, just click on the corresponding COM port. Yves did a phantastic job upon achieving all this!

The best part is: You can have many Interface A attached to LEGO Blockly - or 4 in DOSBox-X using the 4 standard ISA addresses. DOSBox-X can handle even more, but that is a bit more tricky, I believe. Maybe not.    

Here is to Yves 
Best
Thorsten

P.S.: If you want me to, I can try to sketch briefly how to get this going.

Serial version ? I was aware you patched a parallel version to get rid of the 9771 card but Serial how could that be ?

[evank]

4 hours ago, Toastie said:

P.S.: If you want me to, I can try to sketch briefly how to get this going.

Yes

On 7/19/2026 at 4:50 PM, Toastie said:

OK, as anticipated - same thing in Max/Hans book. It is not straight forward to get the MSX to read data from the I/O ports (Centronics/joystick). But it is absolutely doable.

But it MUST be really motivating for @evank to do exactly that!!!

BTW: I doubt that TLG ever endorsed LEGO Interface A for usage with "MSX" computers? 

 

That's definitely going to be one of my next projects. Right now I am racing against the clock to finish coding (in BASIC, of course) my Lego Simon game, in time for Brickfair Baltimore next month. The game will have eight rounds of play. Currently it's working with four rounds. I think I can finish it tonight, or definitely by this weekend.

I'll make a Youtube video about the game when it is done.

Then I have to make another video .... I hear @BatteryPoweredBricks will have something exciting soon, and so will I. :)

[Bliss]

5 hours ago, Toastie said:

The red/white wires are optional; inside Int.A, I have wired +9V and (IntA)GND to pins 2 and 4 of the 20 pin port

Are'nt the red/white wires mandatory (Not optional) to bring the 3.3V and GND to pin 1 and 5?

Optional 9V and GND from the Int.A connector pin 2 and 4 are part of the same row that has the Outputs and Inputs (pins 6, 8, ...20) that are aligned with the ESP32 pins so you were able to weld all 10 pins directly including GND and VIN (9v) to power the ESP32 from int.A.

If you do not customize the Int.A to get the internal 9V and Gnd to pin 2 and 4 of its connector, we can power the ESP32 from its usb port using a wall charger right?

1 hour ago, amine said:

Serial version ? I was aware you patched a parallel version to get rid of the 9771 card but Serial how could that be ?

If you read the first couple of page of this current thread, you will see that @alexGS not only patched TCLOGO to run over a parallel port, but also made a patched version using serial1 IO address and that has been proven to work by @Toastie.

All patched version of TCLOGO and other pertinent information on how he patched the files using hexed.it are on his bricksafe page:
https://bricksafe.com/pages/alexGSofNZ/interface-a-tc-logo

 

Edited yesterday at 01:09 PM by Bliss

[Toastie]

3 hours ago, Bliss said:

If you do not customize the Int.A to get the internal 9V and Gnd to pin 2 and 4 of its connector, we can power the ESP32 from its usb port using a wall charger right?

@Bliss

Exactly 1, and this is why powering them from pins 2, 4 of Int.A is optional. If you don't want to open your Int.A you don't have to, you can use any USB power source via the USB port of the ESP32 board.

3 hours ago, Bliss said:

but also made a patched version using serial1 IO address and that has been proven to work

Exactly 2, it was @alexGS who made the patched versions. If I recall correctly, he made the parallel version of TCLogo for his laptop (and general use in legacy computers still having a parallel port of course) as he could not fit a 9771 card into that machine. And secondly, because 9771 cards are ... rare. Since it worked so nicely, Alex also made the serial version, as I wanted to operate Int.A with my Dell laptop, which has just USB ports, and I had made the little Arduino serial to parallel adapter. At that time, we also discovered how TCLogo is addressing the ISA bus to control Int.A (address dec 925/6). Since parallel and serial cards on the ISA bus work similarly to parallel and serial cards using different I/O addresses, Alex patched TCLogo after looking for dec 925/6 (hex 39D, 39E) with the corresponding ISA parallel and serial I/O addresses.

Best
Thorsten

 

Edited yesterday at 04:09 PM by Toastie

[amine]

32 minutes ago, Toastie said:

@Bliss

Exactly 1, and this is why powering them from pins 2, 4 of Int.A is optional. If you don't want to open your Int.A you don't have to, you can use any USB power source via the USB port of the ESP32 board.

Exactly 2, it was @alexGS who made the patched versions. If I recall correctly, he made the serial parallel version of TCLogo for his laptop (and general use in legacy computers still having a parallel port of course) as he could not fit a 9771 card into that machine. And secondly, because 9771 cards are ... rare. Since it worked so nicely, Alex also made the serial version, as I wanted to operate Int.A with my Dell laptop, which has just USB ports, and I had made the little Arduino serial to parallel adapter. At that time, we also discovered how TCLogo is addressing the ISA bus to control Int.A (address dec 925/6). Since parallel and serial cards on the ISA bus work similarly to parallel and serial cards using different I/O addresses, Alex patched TCLogo after looking for dec 925/6 (hex 39D, 39E) with the corresponding ISA parallel and serial I/O addresses.

Best
Thorsten

 

Does it imply you could control an interface A With control lab software over serial using the right arduino program ?

Edited yesterday at 03:22 PM by amine

[Toastie]

49 minutes ago, amine said:

Does it imply you could control an interface A With control lab software over serial using the right arduino program ?

Well. It would be a new, from scratch approach I believe.  

Control Lab expects the serial data flow for 8 encoded sensors, Interface B is cranking out all the time. You'd have to program the Arduino to mimic that flow for 6 dummy sensors (all zeros) and then encode the two remaining sensors as touch sensors. Secondly you need to encode the Control Lab output data arriving at the Arduino to 6-bit parallel out in addition to PWM. Will be tough but appears to be doable.

Best
Thorsten

[amine]

55 minutes ago, Toastie said:

Well. It would be a new, from scratch approach I believe.  

Control Lab expects the serial data flow for 8 encoded sensors, Interface B is cranking out all the time. You'd have to program the Arduino to mimic that flow for 6 dummy sensors (all zeros) and then encode the two remaining sensors as touch sensors. Secondly you need to encode the Control Lab output data arriving at the Arduino to 6-bit parallel out in addition to PWM. Will be tough but appears to be doable.

Best
Thorsten

GUYS @evank @alexGS@Toastie@Bliss

Wa was that ???

Secret  link removed

 

Edited yesterday at 05:13 PM by amine

[Bliss]

1 hour ago, amine said:

Secret  link removed

I saw the link before you remove it...  Why did you remove it?  I guess it is against some rules ?

Anyway, from what I can see, This tc-logo dot com web site is offering another way of connecting a modern computer to interface A by using the very original non patched TCLOGO.COM but with a Custom Dosbox-x software called TC-Logo-Connect.

So rather than patching TCLOGO.COM, they patched Dosbox-x I guess to redirect ISA board address to USB somehow...

They are also offering to buy an arduino USB-C Bridge on tindie.

Edited 23 hours ago by Bliss

[amine]

10 minutes ago, Bliss said:

I saw the link before you remove it...  Why did you remove it?  I guess it is against some rules ?

Anyway, from what I can see, This tc-logo dot com web site is offering another way of connecting a modern computer to interface A by using the very original non patched TCLOGO.COM but with a Custom Dosbox-x software called TC-Logo-Connect.

So rather than patching TCLOGO.COM, they patched Dosbox-x I guess to redirect ISA board address to USB somehow...

They are also offering to buy an arduino USB-C Bridge on tindie.

I removed the link because there will be an official announcement soon. Did not want to spoil the secret....

Edited 23 hours ago by amine

[Toastie]

1 hour ago, Bliss said:

Anyway, from what I can see, This tc-logo dot com web site is offering another way of connecting a modern computer to interface A by using the very original non patched TCLOGO.COM but with a Custom Dosbox-x software called TC-Logo-Connect.

So rather than patching TCLOGO.COM, they patched Dosbox-x I guess to redirect ISA board address to USB somehow...

They are also offering to buy an arduino USB-C Bridge on tindie.

Well - whatever. I like what you/we have accomplished >much< better! Fully transparently developed, no intent to make any money, well documented. If you want to make your own - $5 + shipping. I am absolutely happy!!! Composing the DIY instructions. If you know how to operate a soldering iron: Wait for it. Furthermore: With the ESP32 approach, and being able to use both, legacy LEGO software AND LEGO Blockly, well, there is no reason for me to go the other route. But it's absolutely OK! 

Best regards
Thorsten

P.S.: @Bliss I believe you can remove/add what you want in your own posts ... too bad though that the link was removed. Was it this one ?

https://tc-logo.com/ And this is the interface: https://www.tindie.com/products/control-lab-io/tc-logo-connect/. $18 + shipping.

He is also on EB and makes this "Interface C":  

Well, why not. It's good to have alternatives.

All the best
Thorsten