XMOS chips and the FPGA Arcade Replay

[mongo]

Nobody cares how much it cost to make them.  They also have to be ordered by the customer and the customer must pay a profit and the customer must pay for shipping for all these new ROM chips every 2 years.  So yes the cost of stupid ROMS is massively more than just using some RAM and downloading a file.
And yes around $50.00 is what my dad paid to the computer store for his 3.1 ROMS many years ago.

Costing $50 of your dad's money and "$50.00 of the Earth's resources were senselessly destroyed" are two very different things.

You have completely missed the point.

I'm not sure you had one. You just like to complain.

The ROMS cost massively more than the equivalent RAM in money, time and natural resources.

No, they don't. You have no idea how expensive RAM used to be.

First you start with a 2.04 KS
which then had to be upgraded to 2.1
which then had to be upgraded to 3.0
which then had to be upgraded to 3.1
which then had to be upgraded to 3.1 with patches
which then had to be upgraded to 3.1 with even more patches
which then had to be upgrade to 3.1 with newer patches
which then had to be upgraded to 3.1 with still yet newer patches.  Remember there have been countless upgrades to the AmigaOS ROM since 1990.

8 separate ROMS costs a lot more than 512K or 1MB of RAM.

Just the shipping alone to order 8 separate ROMS might be enough to buy the RAM.

Versions of Kickstart available for the A3000 : 1.4, 2.04, 3.1. That's all. There was no 2.1 for any Amiga and 3.0 was for AGA Amigas only, and no 3.1 with patches ROMs were ever released.

And if you live in any random left-wing country (lets use Britain as an example) then you hafta pay a whopping ridiculous 17.5% sales tax on all 8 of those purchases which means you have to destroy and burn more of the Earth's resources just to pay the tax.  (In fairness my Dad paid 0% sales tax for all his Amiga gear as ripoff sales taxes were illegal in the USA in those days.)

Sales taxes were never illegal in the USA.

The moral of the story is that Write-Once technologies have their uses but they have many disadvantages.  Better to use Write-Infinite if the cost is close to the same.

No, the moral of the story is you have no idea what you are talking about.

I have a 3.0 for my A3000 so you are mistaken.  Maybe you are thinking about Kickstart 2.04 which I also have.

Is that for your A3000 that "didn't come with a Kickstart ROM"?

[wawrzon]

am i reading this correctly? are you sure x-mos chip like those built in into "amigaone x1000" as "xena" can be only programmed once? what would be the point then putting them on board such a system? i think there must be some misunderstanding somewhere.

also the matter of using x-mos ("xena") for emulation has been discussed multiple times and the idea has been defeated, or at least never proven. anything that chip has been ever used on x1k is making few diodes blink. even though there is more sophisticated usage examples on the net, it doesnt look like there is enough interest or skill in the amiga or better say os4 community to utilize it in any exciting way.

[spirantho]

The XMOS chips we're interested in as users are the programmable ones, not the $3 write-once ones - those are for mass produced final designs, you'd be crazy to use one for development, just like you'd be crazy to develop a ROM using mask ROMs instead of an EPROM.

As I understand it, the point of the X1000 was as much as anything to faciliate the introduction of the XMOS chip - which it did, as its presence has allowed Hyperion et al to port the toolchain to AmigaOS. Now the next (lower priced) Amigas can include the XMOS and already the toolchain is ready for them.

I think the main reason nothing's been done with XMOS so far is simply that most people can't afford one - but I don't think they were expecting any much to appear until this coming (Cyrus) generation of AmigaOnes.

I know for myself I already have ideas what to do with it... I want to write a Spectrum emulator using the XMOS as a ULA (just for the heck of it) or maybe just an entire emulator. Why? Because it's fun, not because it's useful (and it's completely possible, incidentally)

On a more practical note, I want to use the XMOS to control floppy drives to enable use of Amiga floppies without a Catweasel. Come to think of it, it could connect to 9-pin joysticks too. Maybe even a SID chip, with the right board. You could probably use it to aid video/audio decoding/encoding too - you just need to keep feeding its 64KB buffer with the right data, that's all.

What I'm trying to say is that people shouldn't write off the XMOS chip because it's not been used yet - we're still very early in the lifecycle of the chip, once lower priced machines come with it (maybe Acube could put one on their low-end boards? It wouldn't add that much to the cost) we are much more likely to see it being put to use.

[JimS]

Actually my first thought was that it could be an interesting chip for us on something like the FPGAArcade with it's DSP like abilities, at least until I read that it can't be reprogrammed. I'd really like to see what could be done with it for flexible mesh vertex processing, image manipulation, MP3 / video encoding & decoding, audio effect processing, particle engines, physics simulation, etc.

I've been thinking for some time that it would be handy to add some SPI ports mapped into a convenient spot in the Amiga's address space. Then you could tack on some custom chips for CPU hungry tasks like MP3 decoding, TCP/IP stack and so on. I guess it depends on how much space is left over in the FPGA after you wedge an Amiga in there.

[wawrzon]

@spirantho
but the whole point of discussion is to take advantage of the chip if/where possible. if there is no advantage then why bother with it, save for fun?

[AJCopland]

@spirantho
but the whole point of discussion is to take advantage of the chip if/where possible. if there is no advantage then why bother with it, save for fun?

Well there clearly is advantage in it, especially since it's almost certainly one of the programmable (many times) chips rather than the ultra cheap write-once $3 kind

The advantage is the hundreds of MIPS worth of processing power, along with DSP and other hardware to take advantage of.
It can be much more powerful in usage specific ways than a CPU but less flexible, less powerful than specialised hardware but more flexible. So somewhere between the two.

[freqmax]

How much does the reprogrammable XMOS cost? and is the same specification?

Perhaps one could run it without using the OTP through JTAG?

[psxphill]

How much does the reprogrammable XMOS cost? and is the same specification?

They don't appear to offer one. It appears you can run code from ram, they have an OTP module that loads data from encrypted SPI flash http://www.xmos.com/products/why/dsp
 
You might be able to do it via JTAG without programming the OTP. Or you could program the OTP with your own simple loader that allows programs to be uploaded to flash. As long as you can reset it externally then you can run whatever you want and whenever you want.
 
However I still don't think the $3 one is worth bothering with. You'd be wanting to look more towards the $25 dollar one to make it worthwhile. They also do ones with usb interfaces, which would also be interesting as then it wouldn't be limited to the FPGA Arcade. Their debug adapter appears to use an xcore itself http://www.xmos.com/products/xkits/debug

[JimDrew]

At that point you are better off with a couple of 100MIPs ST32 micros at $5.00 each... Lots of code space, RAM, I/OS.

[persia]

You can always get into XMOS programming with a US$99 USB device and a PC or Mac.  They are quite nifty devices.  I've been wanting to try one for a long time but have been distracted by another project.

[omnicron10]

I have used the Parallax P8 Propeller CPU on several designs I have done.

8 core CPU

http://www.parallax.com/propeller/

Very nice chip for the price and a lot of code available for use at http://obex.parallax.com/ .

Works a lot like Jim said he would have liked.  Core for Video, Core of CPU, core for IO etc etc.  

They already have done a lot of SID and other commodore projects on them as well.  

If anyone wants a P8 CPU to play with, let me know. I have a few sitting around!  Just PM me.

[psxphill]

At that point you are better off with a couple of 100MIPs ST32 micros at $5.00 each... Lots of code space, RAM, I/OS.

Yes, that was my point. Not that having an additional processor is a bad thing, but having the $3 xmos is pointless for what we'd use it for.
 
Using the $99 dollar xcore development board would be insane, unless you're looking to mass produce something that will fit on it (I think the development boards use the more powerful chips anyway though).

[wawrzon]

what is the point of having foreign coprocessor on amiga/clone? it would either need to run its foreign native code, which does not exist, at least not yet. or had to run amiga chipset and/or 68k emulation, to take advantage of it. on x1k there in no single practical application for the xmos up till now. hard to expect it would be different on fpgaarcade. and if you want a coprocessor why not go for more powerful one? if you already want to attach a foreign device it could be an i7 as well...

[psxphill]

what is the point of having foreign coprocessor on amiga/clone?

It's not an Amiga clone though, it can emulate anything.
 
The idea of using additional processors would be to reduce the strain on the fpga. So if you needed mp3 decoding you could offload that to another chip.
 
I'm not saying I think it's a good idea, put that is the point.

[mikronauts]

I have a lot of XMOS dev kits in my lab; I got them before they went through their renaming kick.

The $3 part being talked about here only seems to expose the internal OTP area that used to be meant for a boot loader to load code from an SPI flash.

It has "4 logical cores" - which really are just hardware threads. The previous chips supported up to eight threads per core, and were available in 1/2/4 core variants. Only single core devices were available in TQFP, for the dual core part (each core had 64KB of ram) you needed a QFN-like pakcage, and for the four core device, you needed to go BGA.

These days, for my own designs, I mostly use the Parallax propeller.

[mikronauts]

Ok, I was curious enough to check out the data sheet. The 4 "core" device can still boot of an SPI flash connected to the usual pins X0D00, X0D01, X0D10, X0D11 with an appropriate boot loader.

http://www.xmos.com/download/public/XS1-L4A-64-TQ48-Datasheet%28X2612B%29.pdf