Fleafpga ohm minimig

[Nostromo]

Thanks! So, just before I try and order one:

1. Can I connect any USB keyboard and joypads to play?
2. I plan to hook up the system to a TV. Will there be issues with picture and audio?

Thanks!

[Higgy]

Hi. As I understand:

1. It has USB connectors but uses PS/2 protocol. A lot of USB keyboards are still PS/2 compatible so that is not an issue.
Joypads might be more of a problem but there was talk of wiring in a 9 pin dtype plug on the GPIO to connect original joysticks. I am pretty sure the AMIGA Minimig FPGA port would need this adding in, but hopefully Valentin will add this.
2. It is HDMI out with sound so perfect for TV. There was talk of the potential for adding a 3.5 mm jack to the GPIO port if you were using say a HDMI-DVI converter, but it don't think that was so easy.

Hopefully the Minimig filters will also be included as i think with scanlines and a filter it looks quite good on VGA (this was using a MiST on a VGA monitor).

[Nostromo]

Thanks Higgy

1. I hope we can use USB joypads, something like the PS4 controller or something cheap like a Buffalo SNES style joypad would be perfect.

2. Quoting Valentin himself, this worries me a bit:

"Regarding your suggestion Higgy: I'm afraid it isn't as simple as that. You see, Minimig (as ported to FleaFPGA Ohm) is really only capable of what is intended to resemble 576p (or 576i when Amber is bypassed) screenmode via the video out. It does not upscale nor convert to any other mode (very difficult for me, given my very limited knowledge of the Amiga platform). This limits your display options to TV screens only (I don't know of any dedicated PC monitors that support 576p..). Worse still, minimig core video is clocked at 28MHz, not 27MHz as required for 576p, so some modern digital TVs may 'choke' on the signal while others may not.."

It is too tech for me to understand, but it seems that not all TVs will work. I'd love to be corrected

[Higgy]

I think he was talking about my idea of using DVI monitors. For me i have a number of pc monitors with DVI but they don't have sound so I would need a 3.5 mm jack.

I think Valentin was saying that although DVI and HDMI are digital signals they don't support the same freq/res.

The Flea is setup for HDMI.
Saying that I know the Spectrum Next has had some issues in various HDMI TV's.

[Nostromo]

This bit

Worse still, minimig core video is clocked at 28MHz, not 27MHz as required for 576p, so some modern digital TVs may 'choke' on the signal while others may not..

So basically even if using HDMI there is no guarantee it will work.

[pandy71]

Originally Posted by Akira

Thanks for schooling my ignorant ass.
Here I was thinking they were analog!

Paddle part is analog but circuitry is not highly accurate and as such some AD converter can be created adhoc only with plain FPGA (using LVDS input - 8 - 10 bit is feasible).

Originally Posted by Nostromo

This bit

Worse still, minimig core video is clocked at 28MHz, not 27MHz as required for 576p, so some modern digital TVs may 'choke' on the signal while others may not..

So basically even if using HDMI there is no guarantee it will work.

Probably not... simply analog signal will be resampled with 27MHz i.e. Amiga pixels will be resampled and no longer 1:1 mapped on display pixels, for digital some Amiga pixels can be omitted (active video in Amiga is max 736 pixels). Quality loss will be obvious and Super Hires no longer super.

[Nostromo]

I thought video signal via hdmi is digital?

[pandy71]

Originally Posted by Nostromo

I thought video signal via hdmi is digital?

It is digital, my point was related to Minimig and SCART input on TV.
In digital domain things can be done easier and DVI offer some advantage over HDMI as custom video timing can be used (display capabilities is different topic) - HDMI btw also can use custom video timing however predefined and standardized video modes are preferred and mostly only those are supported.
Side to this - seem best idea to fit native Amiga signal over digital interface is using 720p compliant mode - at a cost of padding video with solid color areas (this can be used to display some additional data like floppy status etc) and reduced video size this is only one way to keep V-sync and pixel 1:1 mapping on lowres and hires video mode, to keep super hires higher video mode such as 1920x1080 or better 1920x1200 resolution is required but then we begin to new discussion on vertical line doubling or other resizing. And as Amiga video can be very flexible it is very difficult to fit all video modes with high quality at the same time (and keep FPGA price low).

[Higgy]

I am feeling a bit itchy today. Why? because a Flea turned up in my house

Fleas have hit the UK!

[Amiga1992]

Great news! Mine has not hit the US yet.
Can't wait to try it out and report back.
Let us know how you like it, Higgy!

[Amiga1992]

Fleas landing in east US too! Excited to try this.

[Higgy]

Hi,

Damn it's small!

Programming the device is pretty easy. Try 'blinking LED' first to ensure programming works. I have only used the Next186 Core (486 PC) so far. Got Monkey Island 2 running last night - Note need to use 4GB and larger for this Core.

Keyboard seems a little issue. Although it seems the Next186 Core is different than the Minimig in detecting 'composite' USB/PS2 keyboards. So you will need a PS/2 keyboard wired to MicroUSB.
With Minimig you shoud be able to use a composite USB keyboard with say a USB to MicroUSB adaptor.

I am buying in short extension leads - MiniHDMI-HDMI, 2x MircroUSB-USB Female & MicroUSB Male-Female extension. - I don't want to stress the connectors.

Looks like loads of cool options on the Minimig Core. wire in 2 joysticks, reset switch, 15/30Khz switch, 3.5mm audio out (need to make small circuit) and serial. I plan on putting it all in a project box with 9-pin dypes etc.

Just need some more free time

[Amiga1992]

Well I gave this a try, at first I had issues with the SD card I guess? It was stuck at the blue Minimig screen. But I redid everything (maybe kick.rom is case sensitive) and it booted to the Kickstart hand.

However I also had keyboard issues. I have a PS/2 keyboard and a PS/2 mouse, but they weren't working, so I couldn't test further. Maybe it is because my adapter has one USB to two PS/2 adapters? So yeah, seems like everything worked fine, but I couldn't really give it a proper go. I will try a regular USB keybaord next as you suggest, Higgy.

Then I tried Next186 and that was a bigger fail, said it didn't find the ROM even though I injected it at the end of the card, I guess it is because it was a regular 2GB microSD card? I don't have any SDHC to try.

So I wrote to Valentin to see if he can shed some light, mabe we need a specific type of USB>PS/2 adapter. I surely wish we could hook a USB hub to a port and connect stuff, because also: What about a gameport? Only way is by wiring a proper DB9? If so, for the time being, I won't be able to test much. But am very excited about the possibilities, and flashing the cores to the unit was really easy! If Valentin makes more of these, I suggest anyone interested in Minimig to get one!

[Higgy]

Akira - Next186 only works on 4GB+ cards. I found the hard way also!!
You also don't get much space free (well a lot for a 486 back in the day!) so most of the 4GB will be wasted so you dont want to waste a 8 or 16gb card on this.

If you don't mind a bit of soldering and buying of a few parts you can make a PS/2 - USB connector, its basically rewiring the connections. I did a bodge and now I am waiting for proper plugs to arrive.

Remember I think MicroUSB was mainly chosen because they are small, they are not MicroUSB so I am not sure if many of the 'normal' adaptors work.
This is also very much a hackers device so wiring/hacking/soldering is expected. It was very cheap (and small) so wiring in gamepads etc is the only option.

[Amiga1992]

Yeah I understood they are not USB, but I have PS/2 devices that weren't working.
(Also docs say maybe USB 1.1 support might arrive, so that's something to look for in the future)

I talked with Valentin and he has come to the conclusion that my adapter is not passive, so that's the problem. He told me one has to make sure the adapter is passive, and sent me a pic of his adapters:



He said:

Originally Posted by Valentin Angelovski

Be aware however that not all PS/2 to USB passive adapters like the one above have exactly the same pinout. Here is the EXPECTED wiring diagram of the correct adapter:

http://www.bougetonile.com/ps2-mouse...ree-download/=

​I think the case colour of that PS/2 to USB adapter also matters in that regard (I went for black ie. something generic, not green or purple...).

For the record, I bought my adapter from our local electronics store here in Australia: http://www.jaycar.com.au/usb-to-ps2-...emale/p/PA0915 (pictured in white moulded casing, but scored black ones instead - guess either of those case colours may be safe BUT it always helps to double-check! :-)

As for the game ports, the docs say that you have to ground the pins to get a response. Is that how Amiga joysticks work? Can I just wire up DB-9 ports?

Don't get me wrong at all, I didn't expect this to be a ready device by any means, and I love DIY and hobby projects like this, I just wanted to make sure I wasn't making mistakes, and in the keyboard case, I clearly was.

[happymondays]

My board has also arrived to the country, so I expect it to be here soon, thanks for sharing your experience so far. Taking a look at the pics, I guess I have the right adapters ready here, so now I only have to wait for the postman, hopefully tomorrow.

[Amiga1992]

I went and tried my luck with some cheap ass Chinese adapters, if I am succesful I Will post.

But I'm leaning more and more towards the idea of just building this into a box like Higgy says he's gonna do. Size will go to shit, but should still remain pretty small. Maybe this could be my first 3D printed project!

[Higgy]

My 'green' adaptor killed 2 PS/2 keyboards After checking the pinout it was switched so sending 5v into ground!!

Will be nicer to have a little moulded adaptor rather than my soon to be made 'home made' converters.

Yeah just wire up a 9 pin dtype. 1 ground from the Flea to the dtype and the internals of the joystick sorts out connecting each button to ground so you don't need loads of grounds. Nice there also is 2 fire buttons.

[Amiga1992]

Originally Posted by Higgy

My 'green' adaptor killed 2 PS/2 keyboards After checking the pinout it was switched so sending 5v into ground!!

I guess I Will crack my adapter open before I even try it and compare to the schematic! But more and more a home made solution sounds best, I have plenty of pcb mountable USB ports around that I can use for this, as well as PS/2 ports.

[Higgy]

My green one was moulded, and filled with plastic so cutting it open really just wrecked it. You could not see the internal pins.

Use wire from say a resistor and stick it into the DIN plug to get a multimeter probe on and you should be able to get a multimeter probe in the USB plug the other end.

Just been scanning eBay and could not find black adaptors with the two recesses as per pic. Fingers crossed my bits will arrive by weekend.