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Atari 800: BIT3 FullView vs XEP80 showdown....


Faicuai

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An 800 I got sometime ago got mercilessly destroyed during transit, thanks to horrid packing... After getting a 100% refund, I salvaged all of its internals, including this baby (which ended up costing me nothing):

 

B4AA2FE6-4D83-4FFC-B5F9-1E6A7DC94806.thumb.jpeg.e3e081fb8f2e1ffd02850a0c7b30ed38.jpeg

 

It is a later-production Bit3 FullView, which after some down-time, it is finally repaired and restored to its former glory. Its CRT8021 (terminally ill) got replaced by a fresh one, including brand new 2KB static ram and assorted discrete-logic components (just preventive care). Also got spares 6545s  but the one on-board seems working perfectly. Now with a stack of parts, it should work for years to come.

 

Do not know about you, but I like closure... Always wondered how the "maligned" XEP80 (which I got a while ago) would stack against he almost-mythical BIT3 (which together with the Austin Franklin are rare finds, nowadays, not to mention their spare parts!). So if you ever really wondered too, you may like what's next.

 

Not sure I could display its image, it turns out that my DVDO iScan HD/+ locked-on instantly on the BIT3... just as well as with the XEP80. But these two (unfortunately!) will not work properly on most CRTs out there, including some LCDs... Here's how they look on-screen with the short (but revealing) benchmark code I prepared for the test:

 

First BIT3 and then XEP80:

 

D72480BD-F7F7-48B1-86EB-803DEDF05107.thumb.jpeg.4baff75aad45953c608ee4e6c23dc37a.jpeg F7E6ACCD-8DA6-440F-992A-77079AA69B89.thumb.jpeg.1b2b050cc2fd38c0abefe3f2cdf24235.jpeg

 

Notice that neither makes optimal use of 480p vertical-scan range, being the BIT3 the worst offender by far, and the XEP80 the most manageable, as it displays almost a fully usable 80x24 range, on PAL-mode (And ensuing font, which is optimized for that scan-range). Both will display 80 columns well, but the BIT3 miisses most of the last line, all of this while wasting some precious scan-lines at the top of the image.

 

Next, is on screen detail and sharpness. Take a look, vis-a-vis, in the same order:

E0D80552-B654-4135-B25B-55F8A2CB6884.thumb.jpeg.864f6821433cc4df49e6741f61806117.jpeg 014D36FD-8101-4265-A2E4-3C42E4F1F25A.thumb.jpeg.6037d7dc9e76bc85fe5fa9a35d3a6c19.jpeg

 

Ignore global contrast and lighting differences, because they were captured at a different intra-day time... But notice how crisper / better defined the XEP80 output is... And the video processor is picking up the difference, clearly. Both viewed through Component Input #1 on the DVDO.

 

Now about timing and speeds (all in Altirra Basic 1.57):

 

Test #1 (240 lines, 80 chars. wide):

   BIT3: 23.8 secs.

   XEP80: 24.5 secs.

   (tried an Action-native compiled version, and results are almost the same)

 

Test #2: full 255 chars. set dump, x10 times:

   BIT3: 12 secs.

   XEP80: 14 secs.

 

Not a big difference in performance, on a typical E:-driver (console) session. There are, however, qualitative differences in the way things move and scroll on-screen, being the BIT3 more fluid (like pixel-by-pixel), whereas the XEP80 being more like char-by-char type of rendering. It is subtle but it is there.

 

The XEP80 drivers are Avery's ULTRA drivers, running at 50fps PAL mode (best overall font). You will need a NTSC / PAL agnostic video-path to enjoy it that way.  Now, as for NOTORIOUS differences between these two:

 

  1. The BiT3 has an on-board video-matrix, which is actionable with CTRL A/B keys... That is SUPER cool, because when enabling 40-col mode, it SHUTS-OFF its 80-col. video port, and my video processor picks that up and auto falls-back to Atari's s-video, all without me ever touching a single button! 
  2. E: cursor-scrolling / moving on the BIT3 does not wrap around like the XEP80, which mimics better the OS behavior. The BIT3 destructs on-screen stuff by scrolling into nowhere?
  3. The BIT3 has NO discernible RAM footprint. All memory is yours, essentially. It does map and banks on most of $D600-$D6FF area, though.
  4. The XEP80 ultra drivers ran the 6502 red-hot all the time, giving you the best pure E: / "console" session performance of the pack. The BIT3 drivers does not strictly enforce SDMCTL, which means at times you will find yourself with ANTIC on, performing DMA just to display an empty Gr.0 screen.
  5. (UPDATE): As for installation, both are very easy to install (thanks to the 800's architecture) but you CANNOT run the BIT3 video-cable out of the expansion bay per the provided BIT3 instructions, as it will eventually damage it, or even slash the expansion-bay shield retainer-posts (plastic) due to the stress caused by the ribbon being trapped between the shield's cage and top cover. Instead, a simple and invisible modification of the top-shield plate will allow you to safely and easily extract the Bit3 video-ribbon:

        88DDCCC5-E2CD-451E-8795-A2606B114DE2.thumb.jpeg.9c8dfe13382045045d5e84e2ce64ce49.jpeg

 

 

Well, that's all for now. The BIT3 is certainly a sweet, well designed piece of HW that remains entirely embeded on the 800, and chews-up NO ram, being pretty much transparent as the main console. It is ULTRA rare nowadays, but the XEP80 is, simply put, a solid, portable solution for ANY system or user, offering commendable E: performance, thanks to Avery's Ultra drivers, with a beautiful, sharp, analog-source signal to boot!

 

Enjoy!

 

 

 

 

 

Edited by Faicuai
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15 minutes ago, slx said:

Thanks, makes me feel better about not having a Bit3 and worse for not having tried out my XEP80 yet.

But you will love more having both, I promise!

 

If you do some console-work (like editing, programming, working with DOS, etc.), go try your XEP80 with Avery's ultra drivers. Make sure you have the right Monitor/vide-path for it. Text output is crisp, pin-sharp, especially in PAL-mode.

 

??

Edited by Faicuai
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Check this out folks, you may find this INTERESTING:

 

These are the system-wide power consumption figures, as of this morning! ?

 

 

System OFF:                                                                                       01.80 w (Power-supply drag)

 

EMPTY : (NO cars in expansion bay, system baseline)                             12.20 w

OS-ROM:                                                                                            14.10 w
OS-ROM + Slot=0 (16KB):                                                                   16.20 w (powerup), 15.80w (settled) (@ MemoPad)
OS-ROM + Slot=0 (16KB) + SupSalt FD100335:                                    16.30 w (Exec Menu), 17.20w (RAM test)
OS-ROM + Slot=0 (16KB) + SupSalt FD100335 + INTEC 32 KB:             17.80 w (Exec Menu), 18.60w (RAM test)
OS-ROM + Slot=0 (16KB) + AltBas (soft-load) + INTEC 32 KB:               17.90 w (RAM-peek LOOP) (SuperSalt ROM = ~0.5w)
OS-ROM + Slot=0 (16KB) + AltBas (soft-load) + INTEC 32 KB + BIT3:    22.50 w (READY prompt, 40col)
OS-ROM + Slot=0 (16KB) + AltBas (soft-load) + INTEC 32 KB + BIT3:    23.10 w (RAM-peek LOOP, 80col, DMA=ON)
OS-ROM + Slot=0 (16KB) + AltBas (soft-load) + INTEC 32 KB + BIT3:    23.00 w (RAM-peek LOOP, 80col, DMA=OFF)

 

ALL of the above exclude any tele-powering over SIO. In comparison, my 800/Incognito reference systems typically draws 10.50w to 12.50w watts WITH 1.0MB of ram, and concurrent HD activity! 

 

The bottom-line is that, in order to drive the 800 fully-loaded on 48KB + BIT3 config, you need the 1050 power supply to deliver power reliably! (without yet accounting for anything else you will power over SIO).

 

The 800's stock power supply (rated at 20w) WILL NOT cut it, on the long run!

 

Have fun!

 

Edited by Faicuai
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11 minutes ago, MrFish said:

I certainly like the XEP80's character set on screen better. The Bit3 display looks a little stretched vertically, and not as readable.

 

Among the things that I did not mention about the BIT3 is that its character set is ENTIRELY re-programmable by the end-user.

 

However, the board is begging for a firmware (separate ROM) reverse-engineering, in order to fine tune vertical-scan video output and a few other things... 

 

But in any case, it seems the XEP80 is outputting a higher spatial resolution. It is PIN-sharp and crisp, right from the get-go (especially when outputting PAL character set).

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4 minutes ago, Spancho said:

Are the schematics of the Bit3 card already available somewhere?
is the ROM protected? I am asking as you said it needs to be reverse-engineered.

Here are my ROMs which I checked (for integrity) against other reference dumps (ended up being identical):

 

bit3-404785-char.bin

bit3-404785-code.bin

 

My board is #404785... In overall beautiful condition, seems barely used.

Edited by Faicuai
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19 minutes ago, Faicuai said:

Among the things that I did not mention about the BIT3 is that its character set is ENTIRELY re-programmable by the end-user.

 

I'd heard that before; I think @warerat posted some information about it once (maybe manual too).

  

19 minutes ago, Faicuai said:

But in any case, it seems the XEP80 is outputting a higher spatial resolution. It is PIN-sharp and crisp, right from the get-go (especially when outputting PAL character set).

 

The two sets are defined quite similarly (in something like a 5 x 9 pixel area); and both look pretty similar; but the Bit3 uses a reverse bit order.

 

  Bit3       XEP80       Bit3       XEP80

 

1608211832_bit3font.thumb.png.f5fcf1df188a933150189725192d46ef.png    2126532794_xep80font.thumb.png.3f6f09b762b7b909cfa98bbb5f28fe0f.png    346354404_bit3font-lower.thumb.png.3262c5c7195a7cb398833702bd60b5d6.png    72952742_xep80fontlower.thumb.png.891e5558d7e6930621d5b68a8c30830f.png

 

Edited by MrFish
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1 minute ago, MrFish said:

 

I'd heard that before; I think @warerat posted some information about it once (maybe manual too).

  

 

The two sets are defined quite similarly (in something like a 5 x 9 pixel area); and both look pretty similar; but the Bit3 uses a reverse bit order.

 

  Bit3       XEP80       Bit3       XEP80

 

1608211832_bit3font.thumb.png.f5fcf1df188a933150189725192d46ef.png    2126532794_xep80font.thumb.png.3f6f09b762b7b909cfa98bbb5f28fe0f.png    346354404_bit3font-lower.thumb.png.3262c5c7195a7cb398833702bd60b5d6.png    72952742_xep80fontlower.thumb.png.891e5558d7e6930621d5b68a8c30830f.png

 

The XEP seems to handle TWO sets... one for PAL and another for NTSC...

 

Which one did you compare?

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6 minutes ago, ACML said:

What is the video signal format of the XEP80 out the RCA jack?

 

Outputs on NTSC and PAL formats. Selectable by SW.

 

As for actual hor/ver. scan, it is merciless. I estimate a minimum of 10Mhz or more of bandwidth.

 

Best results here have been in PAL-mode on my any-format monitor and video-processor combo. Such output is the one shown above. It will juice every single scan-line (and horizontal resolution) your monitor and video-path can handle, from an analog-source signal. 

 

One line (25th, control/status line) is still missing, but from my use of the XEP80 with Atari OS, not that relevant. When I move the cursor, it immediately wraps-around at 24th to 1st, so the 25th line does not seem in active production.  I have not been stopped by it, for anything.

Edited by Faicuai
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2 minutes ago, Faicuai said:

Outputs on NTSC and PAL formats. Selectable by SW.

 

As for actual hor/ver. scan, it is merciless. I estimate a minimum of 10Mhz or more of bandwidth.

 

Best results here have been in PAL-mode on my any-format monitor and video-processor combo. Such output is the one shown above. It will juice every single scan-line (and horizontal resolution) your monitor and video-path can handle, from an analog-source signal. 

 

One line (25th, control/status line) is still missing, but from my use of the XEP80 with Atari OS, not that relevant. When I move the cursor, it immediately wraps-around at 24th to 1st, to the 25th line does not seem in active production.  I have not been stopped by it, for anything.

Thanks.  One other question.  Can you use the XEP80 80 column mode and printer interface capability simultaneously?

 

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18 minutes ago, Faicuai said:

The XEP seems to handle TWO sets... one for PAL and another for NTSC...

 

Which one did you compare?

 

There's only one ROM file that I've seen for the XEP80. It has two sets within; but one is just the control character (standard) font and the other the international font; and I can't see any differences other than those in the two sets. Why, is there some noticeable difference font-wise on screen when running in PAL compared with NTSC (other than the normal vertical stretching)?

 

Another thing to note here is that the XEP80 ROM has unique definitions for each inverse character, whereas the Bit3 does not. These, of course, are not unique in Atari's 40-column stock font either.

 

Also, I don't see any international definitions in the Bit3 ROM; so this is probably part of the reason why user-defined fonts are a feature of the card.

 

Edited by MrFish
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2 minutes ago, MrFish said:

It has two sets within; but one is just the control character (standard font) and the other the international font; and I can't see any differences other than those in the two sets. Why, is there some noticeable difference font-wise on screen when running in PAL compared with NTSC (other than the normal vertical stretching)?

VERY interesting....

 

Then the difference is the result of conversion and encoding of gfx-data over PAL. There is a SIGNIFICANT difference in the XEP80 in NTSC vs. PAL. In NTSC it looks a lot like the BIT3, but still sharper / crisper.

 

In PAL, however, I see the characters being compressed WITHIN their bitmap-cels (!) They look as if they take less vertically, and that's why (among other reasons) the last 24th line becomes almost entirely visible on the XEP80 (in PAL-50). Only 5 or 6 lower-case chars. are partially affected, but still readable.

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2 minutes ago, Faicuai said:

VERY interesting....

 

Then the difference is the result of conversion and encoding of gfx-data over PAL. There is a SIGNIFICANT difference in the XEP80 in NTSC vs. PAL. In NTSC it looks a lot like the BIT3, but still sharper / crisper.

 

In PAL, however, I see the characters being compressed WITHIN their bitmap-cels (!) They look as if they take less vertically, and that's why (among other reasons) the last 24th line becomes almost entirely visible on the XEP80 (in PAL-50). Only 5 or 6 lower-case chars. are partially affected, but still readable.

 

In that case, it would just be down to PAL display characteristics; you get the same vertical compression of characters on a normal Atari 40-column display too.

 

BTW, is the Bit3 being displayed in NTSC and the XEP80 being displayed in PAL, in the images you posted?

 

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25 minutes ago, ACML said:

Thanks.  One other question.  Can you use the XEP80 80 column mode and printer interface capability simultaneously?

 

Not with Avery's Ultra Drivers, it seems. I am not even sure if that is the case with the OEM drivers...

 

I only use the XEP80 for E: / Console-mode work, with Avery's ultra-drivers, which I now have wrapped with a micro-RAM manager for both $96BE and $C668 install addresses (52KB mode in Colleen, thus freeing all E: RAM below $A000)

 

The BIT3, on the other hand, seems to use no RAM between low-and-high OS-tracked ram boundaries. It does use $D6XX extensively. It is like it is not there, after power-up, and with a simple USR($D622) or USR($D623) and becomes your console. 

Edited by Faicuai
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Just now, MrFish said:

 

In that case, it would just be down to PAL display characteristics; you get the same vertical compression of characters on a normal Atari 40-column display too.

 

BTW, is the Bit3 being displayed in NTSC and the XEP80 being displayed in PAL, in the images you posted?

 

YES.

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4 minutes ago, Faicuai said:

YES.

Alright, that explains things. So, the Bit3 should look a little better (shorter) in PAL, and the XEP80 a little worse (taller) in NTSC. I thought you were displaying both in one or the other in your images.

 

Edited by MrFish
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5 minutes ago, MrFish said:

Alright, that explains things. So, the Bit3 should look a little better (shorter) in PAL, and the XEP80 a little worse (taller) in NTSC. I thought you were displaying both in one or the other in your images.

 

I tested XEP80 on NTSC, as well.

 

Appears pin-sharp to my eyes (a bit more than BIT3, in my opinion).

 

There seem also differences in the signal's "black" points. Without adjustment, the XEP80 appears grayish in the background, and I need to cut down brightness from 0 to -9 on the DVDO processor. The BIT3, on the other hand, is much closer to 0.

 

Also, the XEP consumes a net of 5.2watts as I measured today.

Edited by Faicuai
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Interestingly, I created a font set in the same dimensions as used here (when I was making up various-sized mono-spaced fonts for the 8-bit GUI).

 

These images both show 1 to 1 pixel aspect, but look vertically shorter than either of your examples. I could simulate something closer to the aspect you're showing here; but it might be kind of interesting to just load this font into the XEP80 ROM and test it out in Altirra.

 

[Edit Note: On a standard Atari display, this will result in a 53-column soft font.]

 

396069903_5x10(upperlower)scaled.thumb.png.8cb4ba0ae47e2741a107c9dc24e3cd8f.png

 

1059770740_5x10scaled.thumb.png.d749507e0f4fc40d3750485cf627468b.png

 

Edited by MrFish
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1 hour ago, Faicuai said:

Not with Avery's Ultra Drivers, it seems. I am not even sure if that is the case with the OEM drivers...

Printing is not implemented in the Altirra XEP80 driver, but shouldn't be a problem with the original Atari driver. The only restriction that I know of is that printing collides with graphics mode, because graphics takes all 8K of RAM and the firmware doesn't bother to try arbitrating the two.

 

I'm not even sure I have a parallel port printer around anymore....

 

44 minutes ago, MrFish said:

These images both show 1 to 1 pixel aspect, but look vertically shorter than either of your examples. I could simulate something closer to the aspect you're showing here; but it might be kind of interesting to just load this font into the XEP80 ROM and test it out in Altirra.

Can't currently, because the XEP80 has separate ROMs for the firmware and the font and only the first one is replaceable in Altirra -- the font is hardcoded. Probably could make it replaceable, the only thing is that I'd have to implement attribute mode switching on a per-scan basis as this is driven by the ROM and currently the XEP80 emulation assumes it can't change per character.

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22 minutes ago, phaeron said:

Can't currently, because the XEP80 has separate ROMs for the firmware and the font and only the first one is replaceable in Altirra -- the font is hardcoded. Probably could make it replaceable, the only thing is that I'd have to implement attribute mode switching on a per-scan basis as this is driven by the ROM and currently the XEP80 emulation assumes it can't change per character.

 

Yeah, I knew they were separate ROMs (just like with the Bit3); but I guess I'd forgotten about Altirra hard-coding the font ROM. I can't even find where to attach the firmware ROM for XEP80 in Altirra, now (can't seem to see it listed in the firmware manager; maybe my eyesight's going). It works though, because I just tested it with AtariWriter 80. So, it's not like I need to do anything with it; but it's kinda weird I can't locate its entry.

 

Does Altirra support the Bit3 card? I don't see it in the list on version 3.90 (maybe it was added recently)?

 

Edited by MrFish
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