FPGA Replacement Boards

By 8bits4ever

Resident (54)

Аватар пользователя 8bits4ever

17-04-2022, 16:30

Hello people!

I started working on this a couple of months ago:

IMG_7810

This particular board is for the Sony HB101p. It uses its own keyboard. The user htdreams did a colaboration with the membrane-to-PS/2 adapter. There is still some work to do but probably it will be finished next month (at least the hardware side). Something very important to notice is that the board requires no modification to the computer case whatsoever, so it is possible to roll it back to its original condition.

The idea behind this is to make an open source repository with adapter boards for different MSX models, either to be used with the SX-2 core board or with a different FPGA.

For me personally, I think this would be a good way to repurpose busted MSX machines and turning them in something usable...

Im curious about your opinions and ideas.

Cheers!
Daniel

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By sdsnatcher73

Prophet (3666)

Аватар пользователя sdsnatcher73

17-04-2022, 17:14

Wow Daniel! That is so cool!

By hamlet

Scribe (4105)

Аватар пользователя hamlet

17-04-2022, 17:20

Very nice idea, Daniel!

By htdreams

Champion (298)

Аватар пользователя htdreams

18-04-2022, 00:20

Daniel is using his hb101p but i'm using the hb101 japanese model (red one, which is way cooler :-) )

there is some minor differences in external connectors, but we'll see how well it goes

I have prepared the arduino code using available arduino libraries Keypad and PS2DEV and used hb101p service manual to check on keyboard matrix configuration to map the hb101 keyboard to ps2 keystrokes

Also, as FPGA configuration options uses ps2 keys not available in the HB101 keyboard, i've prepared key combinations to allow for them, so pressing both SELECT key + 1..8 numeric keys will allow to control the FPGA (to change volume, video output configuration, speed, slots configuration... etc...)

Best of all, as all of this mapping is done by software in the arduino, it's very easy to include other key mappings to allow using this solution for other msx models, it will be as simple as uploading a configured .ino script to the arduino or even use some input via buttons or any other way to cycle between keymaps (although as probably each msx model will require it's own sx2/fpg adapter to fit connectors and slots positions, it will be easy to upload the configured arduino script)

I have yet to fix a problem with duplicate keypress we detected in some tests, but i think we'll manage to get it right :-)

By sdsnatcher73

Prophet (3666)

Аватар пользователя sdsnatcher73

18-04-2022, 08:01

Okay so now I have some questions Wink

  1. What are PSU options? Will it run of the original PSU?
  2. Will the original power switch be used to turn the SX2 on/off?
  3. Will it have a reset button be available?
  4. Will the SD card be easily accessible? Is it between the 2 joystick ports for this model? Do we need to make an opening in the case?
  5. Could you add a DIN8 RGB output? This would make it easier to connect it to CRT with the most common cable. Of course SX2 needs to be in the right mode for it to work.
  6. Will the leds on the keyboard work? (CAPS and KANA lock)

By 8bits4ever

Resident (54)

Аватар пользователя 8bits4ever

18-04-2022, 10:10

First of all, bare in mind this is not intended to be a commercial project, but a starting point for a repository with boards for as many MSX machines as possible. Thus, the options of connectors, etc. will depend on the particular model (without cutting the case).

Now, specifically talking about the HB101 we are working on:

sdsnatcher73 wrote:

Okay so now I have some questions Wink

  1. What are PSU options? Will it run of the original PSU?
  2. Will the original power switch be used to turn the SX2 on/off?
  3. Will it have a reset button be available?
  4. Will the SD card be easily accessible? Is it between the 2 joystick ports for this model? Do we need to make an opening in the case?
  5. Could you add a DIN8 RGB output? This would make it easier to connect it to CRT with the most common cable. Of course SX2 needs to be in the right mode for it to work.
  6. Will the leds on the keyboard work? (CAPS and KANA lock)

1- It does not use the original PSU (which is inside the case). You need to remove it and use a regular 5v barrel PSU externally

2- Yes, original power switch can be used. Actually, as the original power switch is soldered to the PSU, would be best to use a new switch with same dimensions instead.

3- Reset in the HB101 is on the keyboard, and yes, is working

4- For the SD (between the two joysticks) you need to replace the original (removable) plastic plate with a custom plate I made (3D printed). No cuts needed, just replace the plastic part.

5- Not in this model at least, as there are not enough openings. Besides that, a DIN-RGB cable is not common at all. RGB/VGA outputs trough the DB15 connector as usual on MSX FPGAs.

6- The HB101 has a CAPS LOCK LED, a PAUSE LED and a POWER LED. The first two are part of the keyboard matrix and they rely upon the PS/2 controller to work, which is being worked by htdreams. The POWER LED will be replaced with a custom one to serve as both, POWER and SD ACTIVITY LED

PCB designs, 3D models, etc. will be uploaded to a repository when the board is finished.

By 8bits4ever

Resident (54)

Аватар пользователя 8bits4ever

18-04-2022, 11:30

Here are some pictures of the Joysticks/SD ports:
IMG_7829

IMG_7827