gdjacobs wrote:

I say just go with a Soundblaster compatible DB15 jack so everyone can recycle those game port MIDI adapters.

good idea!

stamasd wrote:

Added DIN connectors for MIDI in, out and a DB15. If the DIN connectors don't fit you may have to mod the case, or leave them unpopulated.

You'll probably have to remove the original 9-pin connector if adding the others. All 4 connectors aren't going to fit in the case vertically (horizontally?) either. And yes, a case mod would be required to use the DIN connectors. Mini-DIN like some other boards have used might be a better idea. If someone has the skill to solder the components to the board, they can make a cable adapter without much trouble. One nice thing about the 9-pin connector, however, is the possibility of using a readily available bracket for the card instead of having to drill out a custom one. I'll check over the schematic later today.

I'm excited for the possibility of a board being available, even just a bare board being available where the end user has to solder down all the components would be an order of magnitude easier than wiring it up on a protoboard. You could always make it available on OSH Park or we could get a group buy together to get the cost down. Maybe this would also get some people involved who are better at programming than I am... While the software works, it is admittedly a hack to get SoftMPU working on the Atmega platform. I think there is a lot of potential for HardMPU with the right software running on it.

I looked over the schematic, and as far as I can tell, any errors must also be in mine because they match. 😎

ab0tj wrote:

I looked over the schematic, and as far as I can tell, any errors must also be in mine because they match. 😎

Excellent. I will commence routing in a day or two, because at work all hell just broke loose and I won't have time to do anything about it today. I've never used KiCAD for routing so I don't know how well it will go.

A quick suggestion (IMHO): Keep the DE9 connector in some form, and make the position match this board so the same bracket can be used: http://www.malinov.com/Home/sergeys-projects/ … sa-fdc-and-uart

It also might not hurt to route the second UART TX and RX and 5V to unused pins the DE9 for some unknown future expansion.

ab0tj wrote:

A quick suggestion (IMHO): Keep the DE9 connector in some form, and make the position match this board so the same bracket can be used: http://www.malinov.com/Home/sergeys-projects/ … sa-fdc-and-uart

It also might not hurt to route the second UART TX and RX and 5V to unused pins the DE9 for some unknown future expansion.

You mean RxD1/TxD1? Shouldn't be too hard (famous last words)

Also I did find an small error in the schematic. R7 wasn't named and didn't have a value. Fixed now in my copy.
Also have to figure out what footprints I should use for all the resistors and capacitors. There's only about half a million options for each. 😀

I'm wondering if the game port should be in line with the opto-isolator? The spec says the opto-isolator and buffer should be on the adapter.
https://www.midi.org/images/specs/midiadap.gif

stamasd wrote:

You mean RxD1/TxD1? Shouldn't be too hard (famous last words)

Exactly.... And 5V in case power is needed for whatever external device the UART is talking to. Of course, jumpers for all 3 lines and a picofuse would be what feature creep calls for here 😀

Actually, jumpers are probably not a bad idea. Instead of just a header for the UART like my schematic calls for, put in a 4x2 header that can be used to access the UART internally or install jumpers to connect it to the DE9. If that makes sense...

gdjacobs wrote:

I'm wondering if the game port should be in line with the opto-isolator? The spec says the opto-isolator and buffer should be on the adapter.
https://www.midi.org/images/specs/midiadap.gif

The way I read the schematic, I think the game port is connected correctly. Connecting the game port adapter runs that optoisolator in parallel with the one that is already on the card. And since the optoisolators are running open collector, they shouldn't conflict unless you connect a midi device to both. I could be wrong though...

Yes, jumpers make sense. And the manual should read : "do not try to use more than one set of MIDI inputs or outputs at the same time" :p
(though from the datasheet the 1284 has an output capability of 20mA or greater on each pin, so it should easily drive 2 or 3 TTL loads if you use several outputs at once; but maybe not, because MIDI signalling is current driven not voltage, so you would probably run into trouble if you try to output to more than 2 devices at once without extra buffering)

How's this? DB9 fully utilized.

ab0tj wrote:

The way I read the schematic, I think the game port is connected correctly. Connecting the game port adapter runs that optoisolator in parallel with the one that is already on the card. And since the optoisolators are running open collector, they shouldn't conflict unless you connect a midi device to both. I could be wrong though...

You're right, the gameport is bypassing it. Just me being blind today. Excellent!

I'm not sure jumpers are the right thing. What about just leaving it up to the board assembler which of the three footprints get populated?

gdjacobs wrote:

I'm not sure jumpers are the right thing. What about just leaving it up to the board assembler which of the three footprints get populated?

I brought up the jumpers for the ability to connect the Atmega's second serial port to the external connector, not MIDI. Just something that can be used for "future expansion" like a second MIDI channel, some sort of external display for those who don't have an MT-32, something like that.

gdjacobs wrote:

I'm wondering if the game port should be in line with the opto-isolator? The spec says the opto-isolator and buffer should be on the adapter.
https://www.midi.org/images/specs/midiadap.gif

I thought about that, but most soundcards don't have an optoisolator on the gameport, and the classic cable (the Creative one, which has been copied/reproduced as standard) does have an optoisolator... so if the DB15 is connected to the optoisolator on the card you'd end up with 2 cascaded optoisolators. That's why I made the direct connections.

I assumed that if one didn't have a cable with optoisolator they'd opt to make one without for the DB9 instead, much easier to do.

(I used this for reference: http://www.cryogenius.com/hardware/sbmidi/)

stamasd wrote:

I thought about that, but most soundcards don't have an optoisolator on the gameport, and the classic cable (the Creative one, which has been copied/reproduced as standard) does have an optoisolator... so if the DB15 is connected to the optoisolator on the card you'd end up with 2 cascaded optoisolators. That's why I made the direct connections.

I assumed that if one didn't have a cable with optoisolator they'd opt to make one without for the DB9 instead, much easier to do.

(I used this for reference: http://www.cryogenius.com/hardware/sbmidi/)

Agreed. I just misread where the gameport connected on the network

ab0tj wrote:

I brought up the jumpers for the ability to connect the Atmega's second serial port to the external connector, not MIDI. Just something that can be used for "future expansion" like a second MIDI channel, some sort of external display for those who don't have an MT-32, something like that.

.

I see. I think the header would likely be enough, but it's not a big cost addition so why not?

Fixed a stray wire at the DB9 connector. Looked like a junction but it wasn't.

(edit) Same fix for decoupling caps. O caps why u h8 me?

Argh KiCAD doesn't have a footprint for 8-bit ISA. It does have one for 16-bit ISA. But the 8-bit wasn't converted from the older version and I'm unable to find one. Grrr.

(edit) I found one in someone's git repository reproducing an AdLib card (neat!) https://github.com/schlae/adlib

stamasd wrote:

Argh KiCAD doesn't have a footprint for 8-bit ISA. It does have one for 16-bit ISA. But the 8-bit wasn't converted from the older version and I'm unable to find one. Grrr.

I haven't used KiCad, but would you be able to steal it from the KiCad files for another board? http://www.malinov.com/Home/sergeys-projects/isa-supervga

ab0tj wrote:

stamasd wrote:

Argh KiCAD doesn't have a footprint for 8-bit ISA. It does have one for 16-bit ISA. But the 8-bit wasn't converted from the older version and I'm unable to find one. Grrr.

I haven't used KiCad, but would you be able to steal it from the KiCad files for another board? http://www.malinov.com/Home/sergeys-projects/isa-supervga

That one won't work because it's in the older .brd format, not in the newer .pretty format that now KiCAD uses. See above for one I found.

(edit) all footprints assigned, v0.4.

Oh, cool!

God help me. Wish me luck.