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(new title): Hard decision, but the answer is pretty clear.


x16tial
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3 minutes ago, Fabio said:

i was thinking: isn't flash memory much slower when written? can it sustain the 12 Mz frequence ?

the vera fpga has proved to be capable to integrate at least the 65c02 cpu and a usb controller: wouldn't be a less controversial saving to use it to emulate an FM CHip in the X16?

The flash on the card is probably just the storage for the FPGA bit stream. My guess (because I'm not familiar with the hardware) is that of the 128 KB of memory in the FPGA fabric, a certain amount of it is going to be allocated as ROM, a certain amount as system RAM and a certain amount as video RAM.

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Posted (edited)

You know what I really want?  Just the VERA.

I already made mention that we're already talking about a  "VERA ecosystem", especially if both X8 and X16 are released, and @Birk reminded me:

Quote

why not release the VERA module?  I'd love to have a video interface like the VERA for some other projects.  This would let me connect something like the STM32 to a monitor or TV, or add some cool features to Ben Eater's 6502 kit.  The VERA could become a whole product on it's own with higher priced versions that could go up to 720 or 1080i/p HDMI.

I already have fully working, fully license-problem free versions of 65xx systems sitting on the table behind me.  They're called the VIC 20 and the C64C.  I'll probably buy a 3rd 65xx system: Ben Eater's kit.   And, at this point, I may or may not buy a Commander Xxx.

But I would buy VERA modules for ALL of those (that didn't have it already).

Especially if there's more than one Xxx platform anyway.

Edited by x16tial
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38 minutes ago, x16tial said:

You know what I really want?  Just the VERA.

I already made mention that we're already talking about a  "VERA ecosystem", especially if both X8 and X16 are released, and @Birk reminded me:

I already have fully working, fully license-problem free versions of 65xx systems sitting on the table behind me.  They're called the VIC 20 and the C64C.  I'll probably buy a 3rd 65xx system: Ben Eater's kit.   And, at this point, I may or may not buy a Commander Xxx.

But I would buy VERA modules for ALL of those (that didn't have it already).

Especially if there's more than one Xxx platform anyway.

I have found my tribe!

There is a definitely a subset of us for whom VERA is the product. Perhaps if we can find enough of us, we can convince the dev team to release it as a separate product.

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13 hours ago, Fabio said:

i was thinking: isn't flash memory much slower when written? can it sustain the 12 Mz frequence ?

the vera fpga has proved to be capable to integrate at least the 65c02 cpu and a usb controller: wouldn't be a less controversial saving to use it to emulate an FM CHip in the X16?

No, I meant as ROM ... one of the things that RAM banks will be used for is to load code or data from SD card to have it available at the flip of the RAM bank ... if it can be in simulated ROM Banks already, that would cover that use.

If that is 2MB of flashROM that is loading the FPGA implementation code into the FPGA, which seems likely, the effective simulated flashROM for the running X8 system will be substantially smaller. Whether it is only enough to hold the Kernel and Basic (32KB), or is substantially more is one of the open questions to be answered by getting the LX8 system specs. It seems unlikely it would be substantially more.

Edit: Aha, it seems if the project sources "unofficially available" are correct, it's 512 bytes of ROM, overlaid on $FE00-$FFFF on power up to load the RAM with the system then quit ... so somewhere between 24KB and 32KB used by the system, depending on how much space the Kernel requires. 

 

Edited by BruceMcF
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59 minutes ago, Wavicle said:

I have found my tribe!

There is a definitely a subset of us for whom VERA is the product. Perhaps if we can find enough of us, we can convince the dev team to release it as a separate product.

Gathering resources, equipment, and foo to start breadboarding my own 8bit here. A VERA would solve a ton of issues. Circuitry to drive video  can be bigger than a main system using available off the shelf.

 

Edited by codewar65
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2 hours ago, Wavicle said:

I have found my tribe!

There is a definitely a subset of us for whom VERA is the product. Perhaps if we can find enough of us, we can convince the dev team to release it as a separate product.

This.

Originally, David was going to sell a C64 cartridge with VERA on it, or stand-alone units. I'd buy a bare unit, and drive it with a Teensy or Raspberry Pi Pico.... 

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2 hours ago, TomXP411 said:

This.

Originally, David was going to sell a C64 cartridge with VERA on it, or stand-alone units. I'd buy a bare unit, and drive it with a Teensy or Raspberry Pi Pico.... 

Man, a C64 cartridge with a GEORAM compatible 512K SRAM (which IIRC uses two registers in Expansion Page 1 to set the page aligned target address of the page window and Expansion Page 2 as the page window itself) and the Vera registers based at Expansion Page 1+$80 space, I'm in on that crowdfund entirely independent of the CX16.

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  • X16 has a TON more RAM -- this doesn't matter with fast SD speeds, that same 8k can be swapped from SDCard rather than switching banks

That won't fly in many cases. E.g. cc64 would exhibit abysmal compile speeds if I were to swap out significant parts of the compiler code to and from SDCard.

Edited by pzembrod
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12 minutes ago, pzembrod said:

That won't fly in many cases. E.g. cc64 would exhibit abysmal compile speeds if I were to swap out significant parts of the compiler code to and from SDCard.

Then what will you do on the X8?

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4 minutes ago, x16tial said:

Then what will you do on the X8?

I'll wait for more info and decisions from the project owners, and then decide what will be feasible. If the BASIC at $8000-$BFFF assumption holds, then VolksForth likely will be. For cc64 I'd have to overwrite the BASIC interpreter, and it would still be a close call.

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1 hour ago, pzembrod said:

That won't fly in many cases. E.g. cc64 would exhibit abysmal compile speeds if I were to swap out significant parts of the compiler code to and from SDCard.

I believe this to be very true.

Switching RAM bank in X16 is the time it takes to write a value to a zero page address, i.e. 3 clock cycles = 375 ns @ 8MHz.

Virtual RAM bank switching would require you to first write the current bank values to disk (8 kB) and then read the new bank values from disk (also 8 kB).

In this thread, @Michael Steil commented the theoretical max throughput of the file system - about 13 kB/s if using (the KERNAL's) byte by byte operations, or 140 kB using the DOS routine macptr (I haven't looked closely on that, but it sounds interesting as the programs I've made have a throughput close to 13 kB/s).

https://www.commanderx16.com/forum/index.php?/topic/346-how-fast-will-sd-card-access-be-on-hardware/#comment-2223

Let's assume you would actually achieve both a read and write speed of 140 kB/s. First writing, and then reading 8 kB would take like 0,11 seconds. At 13 kB/s it would take about 1.23 seconds, by the way.

0.11 seconds is quick, but compared to X16 bank switching it's very slow. In fact, you could make about 293,000 X16 bank switches in the time it takes to do one virtual disk based bank switch (assuming read/write speed of 140 kB/s).

This doesn't mean that the X8 is useless. It means that the X8 and X16 requires fundamentally different thinking when you make programs. And some programs that need to use banked RAM a lot will be virtually impossible to port from X16 to X8.

I would certainly miss the real banked RAM of X16 if this project ended up being the X8 (only). The banked RAM is what opens so many opportunities for interesting 8 bit programming.

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Luckily David had confirmed that the X16 is going ahead, so "X8 only" is not one of the options on the table.

Note that for data, if one is willing to sacrifice video capabilities, you can readily use Video RAM for data storage. It would be just like a small GEORam ... write the high byte of the address to the video page register, the page appears at $0400. If X8 load into Video RAM works, that's where I am going to put my Block files in the X8 version of xForth.

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4 minutes ago, BruceMcF said:

Note that for data, if one is willing to sacrifice video capabilities, you can readily use Video RAM for data storage. It would be just like a small GEORam ... write the high byte of the address to the video page register, the page appears at $0400. If X8 load into Video RAM works, that's where I am going to put my Block files in the X8 version of xForth.

Now this is a fun idea! Hadn't thought about that ...

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Posted (edited)
4 hours ago, pzembrod said:

As others have pointed out before: Things aren't as clear as you believe them to be.

Of course they aren't.  And I already said that assumptions are being made. But that could be easily remedied. By giving us access to all of the info and the emulator. This isn't being done and is the source of my frustration.

This board might be less trafficked than the facebook group, but I'd argue the stronger supporters are here, where else is there software being released for the platform?  Of which, myself, I've released some and have more in the works.

I immensely appreciate what the team has done so far. But we're ready, willing and able to pony up real cash for this/these products.
We're being asked if we want one of the said products, but we're being denied access to most of the information about it.

How is that not frustrating?

Edited by x16tial
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2 hours ago, pzembrod said:

Now this is a fun idea! Hadn't thought about that ...

My idea has always been to have block files as 8K segments of loadable files, with the base block number implied in the filetype, .B00 to .BFF, for up to 2MB in a single block space. The C64 version would load a single block segment underneath Basic ROM, access to another block in the segment would be straightforward, and if another block segment is referenced by the BLOCK word, copy from the block buffer to the block segment in RAM if the block buffer dirty bit is set, SAVE the block segment if its dirty bit is set, and load the desired block segment.

And then in the CX16, perhaps four to eight High RAM segments allocated to a LRU stack of Block segments, so a lot less potential for block thrashing.

The imagined High RAM usage is a bit of a three ring circus, with the dictionary contained in a chain of High RAM segments, the BLOCK word looking at the current block buffers, if they are not the requested one looking at the current block segments, loading the required one over the Least Recently Used one if necessary ... and library modules (with embedded dictionary to avoid springboarding) in their own High RAM segment, with the module call primitive handling the selection of the correct High RAM segment.

So just like the C64, the library modules would not be an option in the X8, and the dictionary would just build down from the end of regular RAM (as the alpha version of the CX16 xForth does right now), but hopefully it would be possible to have a couple of 8K block segments stored in video RAM. Copying four pages to and from the 1K Block Buffers a page at a time seems like it would be straightforward enough.

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2 hours ago, x16tial said:

Of course they aren't.  And I already said that assumptions are being made. But that could be easily remedied. By giving us access to all of the info and the emulator. This isn't being done and is the source of my frustration.

I've said it before and am saying it again: Give them a break. Also, you are starting to sound somewhat entitled, which probably isn't your intention.

Quote

This board might be less trafficked than the facebook group, but I'd argue the stronger supporters are here, where else is there software being released for the platform?  Of which, myself, I've released some and have more in the works.

Careful hint 🙂 : You may be, just maybe, overestimating the value of your so far released X16 software. 🙂

Quote

I immensely appreciate what the team has done so far. But we're ready, willing and able to pony up real cash for this/these products.
We're being asked if we want one of the said products, but we're being denied access to most of the information about it.

David is currently dealing with a major shakeup of his project. He's asked a question 5 days ago to feel the water about the option of an X8, and could probably spend some significant portion of his time just reading and digesting all the replies he's getting here in the forum, plus keeping an eye on all the other discussions, such as this one. He has given us an overview of the X8's specs, and I'm not surprised at all if he didn't have the time yet to reply to all the questions that came up.

It shouldn't be all that hard for all of us to muster the patience that is called for at the moment.

Quote

How is that not frustrating?

See above - let's be more considerate of all the other things on the project owners' table at the moment. And keep in mind - they have day jobs, too. This here isn't really it, not even for David, IIUC.

Edited by pzembrod
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On 8/22/2021 at 4:57 PM, Scott Robison said:

Agreed on IEC. It is nice from a nostalgia perspective, but it's not like the fast loaders that depend on 1541 are going to work on X16. The best reason I can see for IEC is not disk drives, but perhaps printers if anyone has those they want to use.

It's a serial port, right?  Could be used for lots of things.

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1 hour ago, Carl Gundel said:

It's a serial port, right?  Could be used for lots of things.

Sure, it could. A recent demo where it was used to generate video proves that. But it was never designed as a general purpose IO port. Maybe someone would repurpose it, but a more general purpose solution seems like it would be better than recreating IEC for the sake of nostalgia.

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37 minutes ago, Scott Robison said:

Sure, it could. A recent demo where it was used to generate video proves that. But it was never designed as a general purpose IO port. Maybe someone would repurpose it, but a more general purpose solution seems like it would be better than recreating IEC for the sake of nostalgia.

Though whatever that more general purpose solution runs the risk of being denounced as "feature creep".

One thing it would have been would have been pretty cheap and easy to include, since IEC handling code would have been in the original KERNAL source that they licensed. Unless I get a clone of a 1581, the only things I can see using it for is sneaker-netting things between a C64 and a CX16 using an IEC2SD, and seeing if some IEC emulation code for a modern microcontroller plugged into the user port as a server of some sort can be used to allow the CX16 to load the client side installation routine direct from the microcontroller.

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Lurker here! Hello all. 

The X8 is great, but if you look at the open source ZX-UNO (which has been forked with a VGA version), you get everything the X8 has plus you get real game ports, 512K of SRAM, PS/2 port, and an expansion port!

It would probably be trivial to change the game ports on the UNO to SNES style controllers if that is what David wants.

To me the X8 feels like a design constrained by the skills of the FPGA designer - someone knows the X16 FPGA (I forget is it Xilinx? Lattice?) and that specific FPGA toolchain really well and is shoehorning the design into that FPGA when we could have all the things we want, memory, real ports, and expansion, going with a ZX-UNO forked solution.

And the cost would likely end up about the same.

I will buy an X8 as soon as it is released if David chooses to release it, but I will always be annoyed by the fact the design was unnecessarily constrained by the selection of the FPGA and there were plenty of templates that the X8 could have been built off of (ZX-UNO, etc.)

 

Edited by Lasagna
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8 hours ago, Lasagna said:

Lurker here! Hello all. 

The X8 is great, but if you look at the open source ZX-UNO (which has been forked with a VGA version), you get everything the X8 has plus you get real game ports, 512K of SRAM, PS/2 port, and an expansion port!

In other words, you get the X16e, except with a different processor family, a different video system, and a different audio system. The various prices of ZX Uno board builds I see in a quick google are €100-€150, which subtracting VAT and doing the exchange is about $100-$150.

8 hours ago, Lasagna said:

To me the X8 feels like a design constrained by the skills of the FPGA designer - someone knows the X16 FPGA (I forget is it Xilinx? Lattice?) and that specific FPGA toolchain really well and is shoehorning the design into that FPGA when we could have all the things we want, memory, real ports, and expansion, going with a ZX-UNO forked solution.

And the cost would likely end up about the same.

Sure, it might "feel" like that to you, but going with thinking it through instead, the idea that it was designed the way it was because the designer was not sufficiently skilled to design a CX16e is not really that likely.

At present, the X16e CANNOT be designed, because the board that it emulates is only in the prototype stage.

So it seems reasonably clear that the X8 was a proof of concept, showing how much of the X16 as it existed could be fit completely into the FPGA that they were using.

Compared your "he tried to do the X16e but he's not skilled enough to succeed" theory, the proof of concept theory is actually plausible. When they came up with the "three phase" approach, they would want to know how much it would cost. Seeing how far the Vega FPGA alone could go would be a valuable piece of information to judge which larger FPGA in the family would be needed.

It also would give them a data point on whether to freeze the Vera feature set, since giving in to clamoring to make it more of a 16/32 bit era video chip would impact the size of the FPGA as well.

As far as the cost ending up the same, no, almost certainly not. If you move from a ZX-Uno or CX16e type system to the X8, the price is going to fall substantially. The 16Xe might be a touch cheaper, since the ZX Uno has a Z80 core, which is a lot bigger than a 65c02 core. But the estimate of the X8 being half the cost of an X16e ... therefore under half the cost of a ZX Uno ... seems reasonable.

Indeed, the ZX-Uno could be seen as one more argument for dropping the ZX-Uno / CX16e type "two chip" device and doing a "one chip" device instead. While not compatible with the CX family, the equivalent of a CX16e has already "been done". The X8 is far more like being breaking fresh ground.

Edited by BruceMcF
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8 hours ago, BruceMcF said:
Quote

In other words, you get the X16e, except with a different processor family, a different video system, and a different audio system. The various prices of ZX Uno board builds I see in a quick google are €100-€150, which subtracting VAT and doing the exchange is about $100-$150.

No the ZX-Uno already has several 6502 cores available that you could build VERA on top of within the FPGA. You would have the same processor, video subsystem, and audio system if an X8/X16 core were built on the ZX-UNO hardware.

No the ZX-Uno is usually around 70 Euros with VAT and would be much cheaper if produced in larger quantities.

https://amigastore.eu/en/650-zx-uno-zx-spectrum-based-on-fpga.html

Quote

Indeed, the ZX-Uno could be seen as one more argument for dropping the ZX-Uno / CX16e type "two chip" device and doing a "one chip" device instead. While not compatible with the CX family, the equivalent of a CX16e has already "been done". The X8 is far more like being breaking fresh ground.

X8 is already a two chip device with an ESP32 for wireless..

 

 

Edited by Lasagna
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