ZX Spectrum next... Anybody backing ?

[northernbob]

viewtopic.php?f=25&t=14154

may be of interest....

IF i can get a board cased up ill bring one along...

[alchresearch]

Yep, I'm an Early Bird backer!

[vanpeebles]

Hi Andy, how are you doing? I used to get AlchNews, years ago

[northernbob]

some info released today....

https://pastebin.com/TT2T53cJ

cant say i fully understand it, bits of it make sense.

[BigEd]

That seems to be a UCF file, which tells us what the FPGA is connected to. And its header says it's open source, which is good.
It indicates there's a 16-bit RAM (but with no byte enables) with up to 19 address bits and up to 4 chip selects
and 28 signals going off to the Pi connector
and (broadly) the expected Spectrum expansion pins (haven't checked them in detail)
and 3:3:3 bits of R:G:B
and a 50MHz input clock (although that doesn't mean a lot given the on-FPGA PLLs)
and, perhaps, output clocks at 3.5, 7, 14, 28, and a 140MHz HDMI clock.

[hoglet]

It indicates there's a 16-bit RAM (but with no byte enables) with up to 19 address bits and up to 4 chip selects

The RAM device used is the IDT 71V424-S10YG
https://www.idt.com/document/dst/71v424-data-sheet

This is 512K x 8, so hopefully they have given each device it's own chip select, meaning byte enables are not necessary.

See:
https://www.specnext.com/instructions-f ... ext-board/

Dave

[BigEd]

Interesting... so we have normally just two or maybe 4 byte-wide chips, for an 8-bit system, but we have a 16 bit wide bus to the FPGA. That's kind of handy, for later cores which are 16 bits wide - and perhaps that's the reason. I had just assumed the chips themselves were 16 bits wide, which was wild and irresponsible.

[crj]

Note that external bus width and CPU microarchitecture don't need to correspond. The Motorola 68008 had 32-bit registers and a 16-bit internal data bus, but an 8-bit external data bus. Conversely, PC DIMMs are 64-bit despite being initially appearing in machines with 32-bit x86es.

[northernbob]

3 boxes left for me, in the back garden by the YODEL delivery bloke!

picsin morning...

also this is waiting for me, at the local RM depot.

[northernbob]

for biged...

there a restriction on file size for pics?

[northernbob]

couple more...(see if anyone is sharp eyed)

[BigEd]

Oh, very nice indeed! I see a number of resistors and resistor networks near the edge connector - I'm interested to find out how 5V-compatible it is.

[BigEd]

...and I see you've already fitted a Pi Zero to one of them! (Need some kind of male-to-male adapter? Or soldered a socket on the Pi?)

[northernbob]

so someone here familiar with accelerating a beeb core in an fpga?

eg if i let you tinker on one of my next boards, you stand a good chance of getting the pi working as a copro?

have asked for the correct procedure to change the core......https://www.specnext.com/forum/viewtopic.php?f=10&t=866

how would a beeb core understand the ps2 keyboard?

what info are we missing to try this?

mark, answer ya fbk msgs

[hoglet]

how would a beeb core understand the ps2 keyboard?

Part of the Beeb core needs to map the PS/2 key codes to the BBC Key Matrix row/col, for example using a massive case statement:
https://github.com/hoglet67/BeebFpga/bl ... d.vhd#L214

[fordp]

Maybe we need a new thread for BeebFPGA on the Next?

I have a feeling this platform will be more popular than all the others put together and more. At least for me

As it is a Beeb it can go in the 8 bit hardware section

[hoglet]

Maybe we need a new thread for BeebFPGA on the Next?

Here you go....
viewtopic.php?f=3&t=14181

[northernbob]

erm, hope i havent put my foot in it, but ive let jim bagley know about the beeb interest in the next.

doubt hell mind or care tbh....well i dont think hes got time to care!! as you can guess the team of 4 are mentally busy, fixing bugs etc.

however he might be able to get some info out of victorT.

[northernbob]

for a laff...

one the lads in the gui grp came up with a new case design!!

[BigEd]

Have you had your three boards working yet?

[northernbob]

ok there is some confusion about my pizero.

some folk are telling me the female header is on the wrong side of the pi...i bought it off ebay like this.(see pic above)

doesnt this only matter if it was going inside the official case?

little quote i saw, someone asked this...

`TBU file is the Core. FW file is the FIRMWARE (Which is a misnomer really). Imagine something like the "BIOS". You do not need a core unless you need to upgrade the hardware`

i think some chip was preflashed with the core, at the factory? u13?

sorry but info been coming thick and fast this week, and i havent retained it all....am gettin auld!

[hoglet]

some folk are telling me the female header is on the wrong side of the pi...i bought it off ebay like this.(see pic above)

The header on the Pi Zero is normally a male header, fitted to the component side. (i.e. the same as every other Pi)

If the Spec Next team has decided to use a female header on the Pi Zero and male on the Spec Next, it's anyone's guess which side of the Pi they expect it to be fitted to. This is down to how the Spec Next board has been routed.

The photo on this page does show the header on the opposite side.

Don't plug the Pi in until you are 100% sure about this.

If you have a meter, you could check which pins on the header are connected to ground.

Dave

[BigEd]

Highly relevant blog post:
https://www.specnext.com/next-accelerator-files-v0-1/

Edit: taken down... photo might still be here:
https://www.specnext.com/wp-content/upl ... _small.jpg

[northernbob]

ok its here the first playable next game. well the first one thats impressed me anyway.

yeah ok its a demo, but damn!


https://youtu.be/2HhGNNP3JMY

no way to get vids to thumbnil on this board?

[BigEd]

Oh thanks, that's a nice demo of the interface too - browsing for tape images and snapshots.

You have to make your own thumbnail, I think:

[crj]

Hmm. This sort of thing makes me realise many people experience retrocomputing in a completely different way from me.

It's cool to play with old hardware. It's cool to run old software. That game looks reasonably fun. But aren't they just running a modern game on modern hardware?

[richardtoohey]

Yes, I was thinking along the same lines ... is it real a Spectrum game? It doesn't look like one!

But there is a retro element in that it is 8-bit Z80 (well, emulated, I'm assuming) so it's not a completely new/modern machine.

Will these be publicly available (and I don't mean second hand ones) or only if you backed the campaign?

EDIT: looks like there's going to be online ordering: https://www.specnext.com/product/zx-spe ... -computer/

[BigEd]

It's an FPGA based system, on a board which can be retrofitted into a dead Spectrum case, or bought in a shiny new but authentic case.

By default it runs as a Spectrum, but with ability to run with any of the many semi-standard enhancements from back in the day. Including several enhanced graphics modes, and also including solid state storage. But it can, I think, still do tape.

Because it's FPGA based, it's acceptable even to many of those who don't feel embedded emulation is authentic.

And it has HDMI video (I think) so it's much more compatible with the modern telly.

I think it's one of the more authentic modern recreations although of course if you insist on a 40pin Z80 inside, it won't be what you want.

[jonb]

Warhawk looks like Xenon on the ST:

https://www.youtube.com/watch?v=dz-IMa1j1d8

..sort of. I mean the game play is pretty well the same. It is impressive but looks very un-Spectrum like, apart from the right hand panel.

Is that a bad thing? I think not.

[crj]

I think it's one of the more authentic modern recreations although of course if you insist on a 40pin Z80 inside, it won't be what you want.

I completely understand why people would want a Spectrum Next for running old games, connecting old hardware, etc. That makes total sense.

I completely understand why people are still writing video games for retro hardware.

But writing a new game which only runs on new hardware... that's just... writing a video game. Isn't it?