XEP80-II a new beginning

[+scorpio_ny]

On 9/11/2022 at 4:08 PM, mytek said:

I almost hate to say it, but the race is on between VBXE 3 and Sophia 2. If the VBXE 3 comes in close to the same price as the Sophia 2, it makes me wonder if Sophia will even be a viable purchase, since the VBXE3 will do all that it can do plus having higher resolution modes and a Blitter. Then the extra icing on the cake will be the standardized HDMI output. Sure you can get converters to go from almost anything to HDMI, with some working better or worse than others, but that's an added cost which needs to be factored in.

In one sense, I agree with this statement and on another, I do not. While VBXE give a lot more capability, if I understand correctly, it still requires the original Antic chip. With the Sophia 2, you have a modern replacement for the GTIA chip. I think if VBXE offered the ability for users to replace a defective Antic chip, it would probably enjoy wider adoption.

[+mytek]

10 minutes ago, scorpio_ny said:

In one sense, I agree with this statement and on another, I do not. While VBXE give a lot more capability, if I understand correctly, it still requires the original Antic chip. With the Sophia 2, you have a modern replacement for the GTIA chip. I think if VBXE offered the ability for users to replace a defective Antic chip, it would probably enjoy wider adoption.

I've rarely encountered bad Antics, but I have had a few bad GTIAs. So based on that a Sophia 2 could come to the rescue in that situation. But then again GTIAs are not very expensive, and the same goes for the older type Antics. I certainly wouldn't base my buying decision on the idea of replacing a chip.

[+scorpio_ny]

25 minutes ago, mytek said:

I've rarely encountered bad Antics, but I have had a few bad GTIAs. So based on that a Sophia 2 could come to the rescue in that situation. But then again GTIAs are not very expensive, and the same goes for the older type Antics. I certainly wouldn't base my buying decision on the idea of replacing a chip.

Pokey chips were plentiful and inexpensive at one time too. Also, the Sophia 2 and VBXE has some utility. It is nice option for those who do not want to radically modify their NTSC 600XL's to get it too connect to a display. Both Sophia and VBXE offer capabilities that users are looking for. Why not also be a viable replacement part too?

[chevymad]

The sophia will automatically switch from pal to ntsc though, which is sweet. If the VBXE offered that as well, one could switch a machine back and forth by switching the clock on the vbxe. 

[+mytek]

12 hours ago, scorpio_ny said:

Pokey chips were plentiful and inexpensive at one time too. Also, the Sophia 2 and VBXE has some utility. It is nice option for those who do not want to radically modify their NTSC 600XL's to get it too connect to a display. Both Sophia and VBXE offer capabilities that users are looking for. Why not also be a viable replacement part too?

I'm not dismissing the chip replacement aspect, and I'm not saying that either upgrade is not worth having. Actually quite the opposite, I agree that they're both great alternative video upgrades that are highly desirable. However I'll stick to my original opinion that if they are both offered at close to the same price point by the time the chip shortages are over, it appears to me that the new VBXE 3 will be the better purchase.

Because the VBXE 3 has these additional features that Sophia 2 doesn't...

• True HDMI output via standard HDMI jack (and likely a way to stream the audio over the same jack)
• Hardware multi-color 80 column mode
• Extended high resolution multi-color graphics modes
• A Blitter
• And probably more that I'm not privy to at this time

Beyond these added features, it'll likely do all of what the Sophia 2 can do.

 

And I probably shouldn't say it, since this topic is about the XEP80-II, but I also wouldn't bother getting one of these (an XEP80-II) unless you have a program you like using that specifically needs an XEP80 to work, or you just want to take a walk down memory lane   Because the VBXE 3's multi-color capable 80 column output is definitely going to be superior, and much faster.

 

11 hours ago, chevymad said:

The sophia will automatically switch from pal to ntsc though, which is sweet. If the VBXE offered that as well, one could switch a machine back and forth by switching the clock on the vbxe. 

Well almost... with the Sophia 2 you still have to switch the main crystal frequency and the type of Antic chip as well. And for those that have NTSC machines that they wish to be PAL, they'll also need to either populate the PAL color burst oscillator circuit on the motherboard or use the PALburst board developed for the 576NUC+.

 

It's not like you can just install a Sophia 2 and automatically go from NTSC to PAL and back again without having to open up the machine and change stuff

Edited September 18, 2022 by mytek
Edited for clarity

[chevymad]

That's why I was wishing the VBXE would replace antic and be swappable as well.. I'd actually use both and then you could switch back and forth either swapping the jumper on the vbxe or perhaps creating an electronic switch or U1mb control for it. The 1088XEL would be perfect for this. 

 

I too am wanting a VBXE3. I've got 2 vbxe's now and a sophia 2. The sophia has the best and easiest picture, but the vbxe of course is more then just a display adapter. 

[+mytek]

20 hours ago, chevymad said:

That's why I was wishing the VBXE would replace antic and be swappable as well.. I'd actually use both and then you could switch back and forth either swapping the jumper on the vbxe or perhaps creating an electronic switch or U1mb control for it.

Aww yes I get where you're going now 👍

 

That would be extremely nice, although buying both devices to get this feature would definitely lighten your wallet considerably. And the Sophia 2 would end up being redundant in this application other than allowing for the NTSC/PAL GTIA automatic switch. Just guessing here, but I believe that would set you back $250 by the time all was said and done (cost of each device, plus shipping from two different vendors).

[+mytek]

20 hours ago, chevymad said:

The sophia has the best and easiest picture, but the vbxe of course is more then just a display adapter. 

Just for clarity, that part of you're statement refers to the present day VBXE as compared to either the Sophia DVI or Sophia 2, not the upcoming VBXE 3.

[chevymad]

Yes. My sophia has the clearest pic and is easiest because it can hook up to any hdmi tv without using an OSSC or something. Though now that my vbxe is hooked to an old vizio through the ossc, the pic is much better then it used to be with the dell monitor. 

[+Larry]

Bump...

@mytek These have been available long enough to get some feedback, I'd think.  Have you heard of any reports of overscanning on the XEP80-II?  I've recently taken my XEP80 out of "mothballs," but the overscan issue still has me.  It's probably time for me to throw in the towel with the original.

[+mytek]

17 minutes ago, Larry said:

Bump...

@mytek These have been available long enough to get some feedback, I'd think.  Have you heard of any reports of overscanning on the XEP80-II?  I've recently taken my XEP80 out of "mothballs," but the overscan issue still has me.  It's probably time for me to throw in the towel with the original.

My XEP80-II OS ROM has modified display attributes that allows true descenders and no-overscan for NTSC, but it does require a more modern 1080P HDMI TV in order to work. Since it takes advantage of every possible pixel, the HDTV needs to allow for a FULL SCAN or what might be called RAW SCAN mode (usually a menu setting).

 

As for feedback, other than someone trying to use this on a DVI monitor (no worky) or an older 720P HDTV (doesn't fully fit screen), I really haven't heard of any problems.

 

If you want to try it with your original XEP80 here's the ROM image: XEP80-II_OS.bin

 

EDIT: Just so we are on the same page... this is the XEP80's OS, not the Atari Computer's OS

[+Larry]

Thanks, @mytek

Yes, I don't suppose the 6502 would like that XEP data! 😄

I presume your OS is for the 2764 on the XEP80 pcb?  I can't find any info on the pcb layout of the original XEP80.  I do have Jerzy Sobola's schematics, but it just lists U7, U12, etc.  I presume you know what is held in the 2364?  Is it the alternative character set(s)?

Thanks,

Larry

[+mytek]

2 hours ago, Larry said:

I presume your OS is for the 2764 on the XEP80 pcb?

No it's U2 (2364) on the original XEP80 that is the OS, or BIOS if that term seems more appropriate. U12 (2764) is for the character set.

 

Original XEP80

 

On the XEP80-II I used the AT28C64B (EEPROM) which is actively in production and is double the size of the original ROM,. Unfortunately this has a slightly different pin-out, although I believe there are adapters available to go from the 2364 to a pin-out that'll work for the AT28C64B. Only the first half (4K of 8K) of the EEPROM image contains the modified version, the 2nd half was the original BIOS.

 

XEP80-II

[+Larry]

On 1/13/2023 at 9:08 PM, mytek said:

My XEP80-II OS ROM has modified display attributes that allows true descenders and no-overscan for NTSC, but it does require a more modern 1080P HDMI TV in order to work. Since it takes advantage of every possible pixel, the HDTV needs to allow for a FULL SCAN or what might be called RAW SCAN mode (usually a menu setting).

 

As for feedback, other than someone trying to use this on a DVI monitor (no worky) or an older 720P HDTV (doesn't fully fit screen), I really haven't heard of any problems.

 

If you want to try it with your original XEP80 here's the ROM image: XEP80-II_OS.bin

 

EDIT: Just so we are on the same page... this is the XEP80's OS, not the Atari Computer's OS

I found my 2364 to 2764 adapters this morning.  So I will give your new bios a try.  Fingers crossed.  It might provide a fix for several owners of original XEP's.

[+mytek]

2 hours ago, Larry said:

I found my 2364 to 2764 adapters this morning.  So I will give your new bios a try.  Fingers crossed.  It might provide a fix for several owners of original XEP's.

I hope it works well for you

 

@phaeron laid the ground work for this in his XEPVHOLD program, and although that stopped the rolling and over scan issues, I didn't like the loss of the lower case extenders in NTSC. So with his help and the datasheet for the VDP chip, I figured out a way to see the whole character, while still displaying all the text lines and then incorporated that into the display parameter aspect of the original BIOS ROM. The beauty of this approach is that the XEP boots up already in the correct mode, no separate driver required (although you still need a program or driver to display 80 columns from the Atari).

[Forrest]

I sent a request to the brewing academy last week, asking to buy the programmed OS ROM and Character ROM chips for $20 for the XEP80 II board. They agreed to my request, and added it to their store! FYI they still have the PCB with the NS405 chip for $25

https://thebrewingacademy.com/products/programmed-chips-for-xep80ii?_pos=2&_sid=699274c18&_ss=r