@AmigaBlitter

Thanks...

Quote:

Some question: it is posssible to create the Xena on PCI. Could the Xena be used in connection with FPGA?

I don't see why not, with a couple of caveats. One is that we don't know how tightly they're integrating the on-board one. It may not be possible to achieve all the same things from one that's put on a PCI card.

If you put it on the Xorro card it is *likely* based on what they've said that you'd be able to hook the XCORE's together using "Xlink" (but again, I don't know yet for sure based on the info that's been released) which is XMOS' way of connecting the chips together using a fast, low latency protocol, in which case the Xena on the motherboard could be used as a "gatekeeper" for any resources on the motherboard it's integrated to.

As for using it in connection with an FPGA, sure - an FPGA looks like any other chip. But it'd mean a custom card, of course. I'm not sure what applications it'd be suitable for, though. Got any exciting ideas? :)

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@AmigaBlitter

Quote:

I'm thinking about to use a Xena card on PCI on the Sam440 Board. The Sam440 have a Lattice XP FPGA programmable on the fly with jtag connectors. I'm not an FPGA expert, but i think that this FPGA could be used with the Xena. Just wondering if a Xena card could be fitted in a PCI 33 slot. Btw, the LatticeXP could become a PCI endpoint too.

It'd take someone to make a PCI card, I suppose. XMOS chips are already available, and quite cheaply, so making one shouldn't be that hard / expensive (you could conceivably use a quad core one and sacrifice a core to handle the PCI interface, which ought to leave you with very little additional circuitry).

Of course until the X1000 is out there's not enough info to make something that is guaranteed to be able to link to the Xena on it directly (the chips support a system called Xlink to get high speed communications channels between them), but from the looks of it it shouldn't be too hard to make it accessible over the PCI bus.

In the meantime, XMOS has plenty of USB based dev boards for anyone that wants to experiment - I'm planning on ordering one myself.

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You know, looking at some of those XCore projects, it might be fun to put one of those LED displays, you so often see them with, on the front panel of your X1000 case. Telling you the time, CPU temp, if you have mail, displaying the weather, telling you how far your torrent has to go, displaying MP3 or video information, acting as a Graphic equaliser, animating an Eric Schwartz Amiga cartoon, maybe a smiling face if it is happy, or an animated face if it is talking (through the "say" command). It would look like a fun project and would make the case look more like a high end appliance perhaps. That would make the X1000 unique looking and literally give it a personality. My Dell Laptop had something like that.... It was pretty much the coolest thing about it. That talking bit kind of reminds me of that Electric Dreams movie.

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@BigBentheAussie

Quote:

BigBentheAussie wrote: You know, looking at some of those XCore projects, it might be fun to put one of those LED displays, you so often see them with, on the front panel of your X1000 case. Telling you the time, CPU temp, if you have mail, displaying the weather, telling you how far your torrent has to go, displaying MP3 or video information, acting as a Graphic equaliser, animating an Eric Schwartz Amiga cartoon, maybe a smiling face if it is happy, or an animated face if it is talking (through the "say" command). It would look like a fun project and would make the case look more like a high end appliance perhaps. That would make the X1000 unique looking and literally give it a personality. My Dell Laptop had something like that.... It was pretty much the coolest thing about it. That talking bit kind of reminds me of that Electric Dreams movie.

This is really a good idea! :) It sounds really cool and there is a market for young people who never knew what an Amiga is. There is a craving for these kind of post-retro things among those people. Retro is so in these days. It seems like a sub-culture that attracts every kind of person.

Hm

Perhaps its would be a good time to contact someone regarding an XMOS pci board, for the mediator? Or perhaps even the clocklport? Or go for my idea about raping the bus, using both clockports, and the unfinished bits, and attach to the chip ram ;)

Last edited by mike on 08-Jan-2010 at 12:56 PM.

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@BigBentheAussie

http://www.mini-box.com/picoLCD-20x2-OEM

Nothing new here. PCs tuning guys are doing this kind of things since ages via usb and it does not require the XMOS chip.

@Amilord

Quote:

Amilord wrote: @BigBentheAussie http://www.mini-box.com/picoLCD-20x2-OEM Nothing new here. PCs tuning guys are doing this kind of things since ages via usb and it does not require the XMOS chip.

yeah, but I was thinking more like something like this one. Preferably blue.
http://www.youtube.com/watch?v=0_BqUjMFz5s&feature=player_embedded#
Edit: Or dare I say this one
Edit: http://www.youtube.com/watch?v=Aj3_v7xCyJ0&feature=related

Last edited by BigBentheAussie on 08-Jan-2010 at 01:43 PM.

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@umisef

At the time, I was assuming that the XCore would be able to utilize the X1000's system RAM. As it turns out, the XCore processors would only be able to use system RAM for storage (if at all).

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@ShadesOfGrey

Quote:

At the time, I was assuming that the XCore would be able to utilize the X1000's system RAM. As it turns out, the XCore processors would only be able to use system RAM for storage (if at all).

AT this time.

I imagine if dedicated RAM were necessary it would go on whatever got plugged
into Xorro.

@Mechanic

Quote:

I imagine if dedicated RAM were necessary it would go on whatever got plugged

And how do you suggest to hook up this "dedicated RAM"? The XMOS chips have no external address or data busses.
Best you could do is using the 32 bit I/O for hooking up to the address pins of some SRAM, and one of the 8 bit ones for a bidirectional data bus.

However, that would require 2 cycles for a byte read, 3 cycles for a write, minimum. So a max of 20MB read-modify-write max, with no processing. A 768x576 frame in 4:2:2 YCrCb is about 3/4 of a meg. At 30fps, about 22.5 megs/s, simply for motion compensation.

@Mechanic

Quote:

I imagine if dedicated RAM were necessary it would go on whatever got plugged

AFAIK based on XMOS' docs, the chips doesn't have a memory bus, but you can work around this by using a thread to act as a memory controller (SRAM controller; there's also an example SDRAM controller).

Memory access speed via the software controller linked to isn't particularly impressive though (30MB/sec) so it's not really an option for things like video etc. at higher resolutions.

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@Mechanic

I meant at the time I wrote my original response to Caveman.

Technically yes, but you would still be limited to swapping in/out 64K, 128K, or 256K pages (depending on the XCores in use) to make use of any extra RAM. That or you'd have to connect enough XCores together to equal the amount of RAM required for a given task. So it's possible, it just may not be exactly practical.

http://www.xmoslinkers.org/forum/viewtopic.php?t=567

Edit:

And yes, as vidarh points out, throughput would play a role in just how effective the XCore would be for encoding/decoding video.

Last edited by ShadesOfGrey on 08-Jan-2010 at 03:56 PM.

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@vidarh

Quote:

Memory access speed via the software controller linked to isn't particularly impressive though (30MB/sec)

And looking at the code, *that* speed is almost certainly only possible when using the controller to access the internal RAM (referred to as "TEST" mode in the source), rather than external.

The implementation given for external memory uses 21 instructions (well, lines of XC, but they all look like they should translate 1:1 into underlying assembler instructions), with a cycle time of 20ns each, to read a single 32 bit word. So 420ns per 4 bytes --- just under 10MB/s, before the overhead of providing this as a service via a channel.

The code seems rather conservative --- it's probably done that way to ensure it's compatible with as many different external SRAMs as possible; So tuning it more aggressively to a particular, known device might buy a factor of 2, or maybe even 2.5 --- but nowhere near enough to do, for example, MPEG video decoding for non-trivial resolutions.

@Ancalimon

Quote:

Quote: BigBentheAussie wrote: You know, looking at some of those XCore projects, it might be fun to put one of those LED displays, you so often see them with, on the front panel of your X1000 case. Telling you the time, CPU temp, if you have mail, displaying the weather, telling you how far your torrent has to go, displaying MP3 or video information, acting as a Graphic equaliser, animating an Eric Schwartz Amiga cartoon, maybe a smiling face if it is happy, or an animated face if it is talking (through the "say" command). It would look like a fun project and would make the case look more like a high end appliance perhaps. That would make the X1000 unique looking and literally give it a personality. My Dell Laptop had something like that.... It was pretty much the coolest thing about it. That talking bit kind of reminds me of that Electric Dreams movie. This is really a good idea! :) It sounds really cool and there is a market for young people who never knew what an Amiga is. There is a craving for these kind of post-retro things among those people. Retro is so in these days. It seems like a sub-culture that attracts every kind of person.

I agree, this would be a cool extra feature, providing the LED display is cheap enough to include as a standard... and imagine a remote LED display, with possible remote control features for a low end amiga in the living room

@Smurfen

I'm still not seeing any advantage to the low powered pluggable processors. I mean if it takes like 256 of them to equal a modern multicore processor why not just stick a second multicore processor in the thing and be done with it?

@persia

Quote:

I'm still not seeing any advantage to the low powered pluggable processors. I mean if it takes like 256 of them to equal a modern multicore processor why not just stick a second multicore processor in the thing and be done with it?

Because most of them don't have bi-directional IO lines that you can easily connect directly to external hardware, and b) you'll have a hard time to find a modern multicore processor that can react to IO with anything resembling the low latency that these chips can.

For desktop OS's on modern hardware, interrupt latency on the order of tens of milliseconds is still not uncommon when the system is under any kind of load, while the XMOS chips can get latency on the order of tens of *nanoseconds* and do so deterministically without any need to add hard-realtime support to the OS running on the main CPU.

It's not for processing power, but for low latency and/or tasks that require custom IO lines.

A second PPC would be far more expensive and not provide that functionality.

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@vidarh

Very good answer!


In short: XCore is about HARD REALTIME.

Traditional standard desktop systems can not even do soft realtime.


Let's see what x1000 will be capable of in practice. So far, to me it seems that XCore was a very good option as the custom chip.

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@vidarh

Ok, but again a latency of tens of milliseconds is not going to make a difference in theatre applications. Remember an eye blink is 300 to 400 milliseconds. A TV frame is 40 milliseconds. We're dealing with an extremely limited number of situations that require a latency of less than 10 ms. For most real world applications it gets back to the "reading the bounce of a joystick" argument on A.org....

Last edited by persia on 12-Jan-2010 at 03:59 PM.

@persia

Quote:

Ok, but again a latency of tens of milliseconds is not going to make a difference in theatre applications. Remember an eye blink is 300 to 400 milliseconds. A TV frame is 40 milliseconds.

*Of course* this isn't useful to everyone, or every app out there. Neither is a lot of other features - for how many percent of applications does it matter to have USB? Compact flash? etc. That it's not useful for everyone all the time or even most of the time doesn't mean it's can't be worthwhile.

Quote:

We're dealing with an extremely limited number of situations that require a latency of less than 10 ms.

EDIT: I realized *I* wrote milliseconds earlier, and that's where you took it from... My mistake. It was meant to be micro seconds. Doh. Ignore the first paragraph below.

You wrote milliseconds earlier in your reply, but I'll assume you man microseconds, as otherwise the above is downright silly - try to do any reasonable audio-processing with a latency of 10ms just to handle an interrupt for example, or most other signal processing for that matter.

Below is a few examples of where this is useful or interesting for some of us. If you don't find any of them compelling, fine, you'll overpay perhaps $5-$7 on your X1000 to pay for your possibly unused XCORE, which I think is a small price to pay for A-Eon getting a few more customers to help cover their R&D costs from those of us who are excited by it.

* Access to old hardware. You have a number of general purpose IO pins that you can hook up to whatever you like: Old Amiga keyboards, disk drives, C64 cartridges or user port equipment - basically anything that is remotely electrically compatible can be hooked up without needing additional components. Latency isn't that important here - many of these are so slow the main CPU could easily drive them *if you had the IO pins available*. You don't. So the alternative then is some dumb IO circuitry, or a dedicated hard-realtime 32 bit CPU that doesn't cost much more.... I know which I'd pick.

* Doing cycle accurate emulation of various chips - including the SID for example. Assuming 10us, that means that if you want to do cycle accurate emulation of a chip - and you'd think emulation is something a decent number of people here care about - and avoid clock drift, you can't even exceed 100kHz with any guarantees.

Beyond that you can still manage to "sort of" do it in the sense that the immediately visible results can be made correct, good enough for many uses, but you need to "cheat" and count instruction cycles and rely on throughput to be high enough to make up for pre-emption by other tasks and interrupts. Even at 1us you're still not able to do more than 1MHz without resorting to "cheats". If you only care about playing your old games, it's likely not to matter for you. But to some of us the cleanness appeals... After all that's much of what attract me with the Amiga in the first place.

* Sound effects box doing live manipulation of sound (yes, a few ms can be noticeable if you want to modify a sound stream to be combined with other sound sources)

* MIDI interface (unless they've picked a sound-card or chipset that has one built in, but this is less and less common - I can't remember the last sound-card I had that came with MIDI support) (yes, I know you can get cheap USB MIDI adapters, or buy a high end sound card, but why, if you already have what you need?), or do realtime transformation of MIDI events... Ok, so perhaps old jibes from Atari ST owners still hurt :P

* Software oscilloscope at far higher accuracy than the main CPU could hope to, thanks to hard realtime guarantees.

* Trivially easy interfacing to hobby projects: LCD panels, home automation, robotics etc. - I'm surely not the only one that remembers the number of homebrew hardware hacks for the classic Amiga's. Heck, I had stuff soldered straight to pins on my M68k in my first A500...

* Network analysis / realtime packet manipulation etc. The main CPU *can* do this, but for many of the types of things you night want to use this for, why burden the main CPU with the extra overhead when there's no need to?

Quote:

For most real world applications it gets back to the "reading the bounce of a joystick" argument on A.org....

Most "real world" applications aren't directly impacted by any hardware interface. But for the ones that are affected it can make a great deal of difference.

And again, it doesn't matter if this is useless to a lot of (or even most) users, as long as it's useful enough to increase the odds of a small number of additional ex-Amiga users (like me) deciding to return to the platform. Just the amount of discussion about it alone indicates to me that it's a good investment for A-Eon to include it.

It is in any case kind of odd to read this focus on raw performance on an Amiga forum, when the best choice if raw performance was the overriding goal would be to use an x86-64 box in almost any situation these days... Low latency task and offloading the main CPU as much as possible has been a part of the Amiga legacy from day one.

Last edited by vidarh on 12-Jan-2010 at 05:05 PM.

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@vidarh

Excellent post.

Xena/Xorro isn't something most people were ever going to 'get' overnight, but it's good to see a few people seeing what it's about pretty quickly.

My guess is that one area where this will get the most traction is as an 'anything controller'. Back in the day, lots of people used Amigas to control all sorts of things, primarily because AREXX made it easy to do what you wanted in software and dump it out to PAR: or whatever for a relatively simple hardware interface. Creating a Xorro board to do this kind of job for a wide variety of weird homebrew or custom hardware is likely to be as simple as sticking a few connectors and buffers/op-amps where necessary on the board.

The point about access to old hardware you make is also an excellent one. Interfacing the hardware is trivial, the rest is just software. Should make multi retro-interface cards a very cheap option, and that's just the kind of thing this market should love.

The real fun should be in seeing what happens when that famous Amiga market hacker ingenuity is let loose on it, though.