Atari 8-bit EPROM Cross-Reference

[Timothy Kline]

Good morning (well, here in Michigan USA), everyone!

 

I'm still scouring the forum topics to piece together the info, but figured I'd at least give it a shot by asking here if anyone has ever compiled some sort of cross-reference for Atari 8-bit EPROMming to show equivalents-- no point in me reinventing the wheel, as it were.

 

For example, for Atari BASIC, the EPROM equivalent is _________.

For Atari OS, the EPROM equivalent is _________.

For Atari cartridges, the EPROM equivalent is _________.

 

And so on, if other 8-bit chips have an EPROM equivalent.

 

Lastly, would/should such a cross-reference include eEPROM equivalents, even though it seems to me that having an erasable EPROM is essentially the same as having an EPROM since an EPROM is erasable...

 

Thank you, in advance!

--Tim

[1050]

XL/XE BASIC rom is 2364

XL/XE OS rom is 27128

Cartridges are next to impossible to work with due to custom Atari roms used for

them. And this was precisely the reasoning for it, still working good too.

Not only did they have switched around pins, but their enable functions also are

sometimes backwards to standard negative enable that standard eproms possess.

 

Similar to but not the same as these two devices:

2364 eprom DSA2IH00218630.pdf

Issue here then becomes finding one and a programmer that has this device in it's

supported chip list. You can find one but can't program it, what good is it?

 

Easiest workaround is to just buy a cartridge board made for standard 2764 eprom

from B&C and use those instead.

 

None of the above addresses supercarts in any way.

 

Have tried to use eeproms in all the above and have not had any real luck yet, so

I'm no help there at all. That work was ten years ago or better though and no

super cheap chinese NOS connection existed then. I might have better luck today

in other words.

 

Since it's such a short list there really isn't much need of one. More rare is the

number of people that need such a list. You might be the first to ask.

1050 OS can use a 2732 eprom.

XF551 OS uses a 2764 eprom.

Other peripherals also use in general standard eproms of which you can read their

type right on them. Obfuscation of the cartridge seems to have tired Atari out

and they gave up the quest at that point?

[+kheller2]

An easy way to remember what size eprom to use is to multiply your KByte by 8 to get your Kbit chip's size.

The OS in the XLs is 16k, so 16*8 = 128. You need a 27128.

1050s are 4K so 2732.

2764: 64/8 = 8, hey basic is 8KB

 

There is actually a good eprom primer out there that discusses what each position in the name means, like: 27C128-x-y. I'll see if I can dig it up. If you want a direct ROM drop in I think you use the 25 series, but that might depend. It's been a while.

Edited June 14, 2016 by kheller2

[Timothy Kline]

An easy way to remember what size eprom to use is to multiply your KByte by 8 to get your Kbit chip's size.

The OS in the XLs is 16k, so 16*8 = 128. You need a 27128.

1050s are 4K so 2732.

2764: 64/8 = 8, hey basic is 8KB

 

 

 

There's NO way it's THAT simple!! O.o

 

 

There is actually a good eprom primer out there that discusses what each position in the name means, like: 27C128-x-y. I'll see if I can dig it up. If you want a direct ROM drop in I think you use the 25 series, but that might depend. It's been a while.

 

Yes, please let me know. I am clearly a moron, and could use a lifeline here, lol!

 

--Tim

[+kheller2]

Yes, for the most part its that simple (ignoring packaging, amount of pins, etc..) (Ignore my 25 series/ROM comment as that isn't entirely accurate. Always check the chip specs and pinouts).

 

I no way support this site, but did find some of their brief information on chips educational: http://www.batronix.com/shop/electronic/eprom-programming.html

Edited June 15, 2016 by kheller2

[Timothy Kline]

Yes, for the most part its that simple (ignoring packaging, amount of pins, etc..) (Ignore my 25 series/ROM comment as that isn't entirely accurate. Always check the chip specs and pinouts).

 

I no way support this site, but did find some of their brief information on chips educational: http://www.batronix.com/shop/electronic/eprom-programming.html

 

Thank you, kheller2! Tossed into Evernote for reading later.

 

--Tim

[unixdude]

Thanks for this info.

 

I find myself wanting to burn EPROMs for my systems, because I have unfortunately destroyed my OS ROM chips.  It looks like I'd need a 27128 (or 27C128) EPROM, but I can't find those today.  Am I out of luck here?

It looks like I have everything else I'd need: there's the MiniPro EPROM programmer, and there's the minipro app for Mac OS X.  All I need to find now are the chips.  Thanks.

[chevymad]

https://www.ebay.com/i/332312337304?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=332312337304&targetid=885291054415&device=c&mktype=pla&googleloc=9033410&poi=&campaignid=9426387774&mkgroupid=92958141302&rlsatarget=pla-885291054415&abcId=1140476&merchantid=115327644&gclid=EAIaIQobChMI9PS0jYOU6AIViONkCh3SawG0EAkYASABEgJpsvD_BwE

[unixdude]

Thanks, yeah, that's what I thought -- only New Old Stock (or used items), and only on eBay.

[manterola]

Another, this time from Canada. 

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F303182370280

[Nezgar]

The canadian set looks OK. Likely not pre-blanked though, but won't be fake.

 

Best prices from China/ebay are when buying lots of 10 or more. I've bought many this way. About 10-20% might be fake - "rebranded". The TL866 may identify them with a different " chip ID"  but they will usually still program with the same parameters. Maybe they think we only want "ST" brand chips...

 

also invest in a UV eraser.. Also easily found from ebay/china.

 

27256 and 27512's are fun if you want to get into using adapters to switch between 2 or 4 OS's on 1 chip, or 2/4/8 different options for BASIC.

[unixdude]

I think OS switching would be fun, yes. 
 

is it possible to load the XEGS ROM into a chip and have that work in my 600XL/800XL, complete with Missile Command?

 

Also, I see the Xgecu TL866II+ on eBay. It looks like that plus some of the linked chips plus the XL/XE OS and David Griffith’s minipro software and I should be off to the races. Am I understanding this correctly?

 

and, good call on the eraser. 

 

thanks. 

[Nezgar]

18 minutes ago, unixdude said:

I think OS switching would be fun, yes. 
 

is it possible to load the XEGS ROM into a chip and have that work in my 600XL/800XL, complete with Missile Command?

 

Also, I see the Xgecu TL866II+ on eBay. It looks like that plus some of the linked chips plus the XL/XE OS and David Griffith’s minipro software and I should be off to the races. Am I understanding this correctly?

 

and, good call on the eraser. 

 

thanks. 

A 27256 can be a drop-in replacement for the XEGS 32KB combined ROM. You can replace the BASIC & Missile Command 8KB segments with two other 8KB games, I've done this for some people. However, the XEGS ROM cannot be directly used in any other XL/XE because the other machines separate out the OS and BASIC to different chips. You can get XEGS-like functionality with the Ultimate-1MB upgrade though... or use a 2364 switcher/adpater to get a selection of BASIC replacements...

 

The TL866 II is limited to max 18V programming voltage, so you can't program some really old EPROM's that require 21V or 25V programming voltage, including 2532, but that should not be an issue if you pay attention to what chips you buy.

 

Here's a link to the cheap eraser I use that works well. I don't trust the timer so I use a timer in my phone, 10-20 minutes is enough for most chips. I added rubber feet and put a screw in the front of the drawer to act as a handle:

 

https://www.ebay.com/itm/141840456258

[unixdude]

I see what you mean about the voltage -- thanks, I'm really starting to understand this.  That first link looks good, but it's 21V, which a TL866II+ can't program.  Now to make sure I find chips I can program!

Edited March 12, 2020 by unixdude

[Nezgar]

2 hours ago, unixdude said:

I see what you mean about the voltage -- thanks, I'm really starting to understand this.  That first link looks good, but it's 21V, which a TL866II+ can't program.  Now to make sure I find chips I can program!

I forgot to mention the TL866 version 1 can program at 21V (but not 25V) which is the model I have.

 

In theory you could MacGyver a higher voltage external power source to the chip if the programmer itself can't...

[unixdude]

Yeah, I'd rather just find chips I can program with it, and it looks like the TMS27C128 is supported by the TL866II+.

 

I have already downloaded and compiled David Griffith's minipro software, so now all I need is the eraser, programmer, and chips.  I'm going to buy the TL866+ from the authorized eBay distributor, and I'll buy that eraser you suggested.  Now it's just finding the chips, and I am now consulting datasheets and the supported chip list to ensure that the ones I buy are supported.

[xrbrevin]

i bought the cheapskate eraser with chinese text on and its fine

there are mods out there for the TL866 - custom firmware and to enable that mysterious port on the end are the ones ive heard of but there may be volt mod info out there

i have a firmware that makes it into a pro version and it works as it should ?

[manterola]

12 hours ago, Nezgar said:

also invest in a UV eraser.. Also easily found from ebay/china.

 

27256 and 27512's are fun if you want to get into using adapters to switch between 2 or 4 OS's on 1 chip, or 2/4/8 different options for BASIC.

I did not invested in a real eprom eraser, I just got a cheap toothbrush sanitizer... It uses some AA batteries and a timer of about 5 to 10 menutes and it actually works, but I need to keep stating the timer again since 1 or 2 passes or even 3 passes are not enough. It works, it is cheap, but If you can spend more money get the real thing.

https://www.ebay.com/itm/Intizar-UV-Toothbrush-Sanitizer-Eliminates-up-to-99-9-of-Germs-Bacteria-PINK/152858601342?epid=1864074481&hash=item239715277e:g:2KEAAOSwY3daU9vc

6 bucks free shipping.. but not very convenient.

 

 

[manterola]

2 hours ago, Nezgar said:

I forgot to mention the TL866 version 1 can program at 21V (but not 25V) which is the model I have.

 

In theory you could MacGyver a higher voltage external power source to the chip if the programmer itself can't...

I would like to program and read the P8050AH intel chips use in the xf551 and clones. for example I would like to extract the FW of my original XF551 which actually worked pretty well. The info is very limited regarding this processor(with included memory),they called this family  the MCS48 something like that. 

Can we MacGyver  TL866 to program those maybe?

 

Edited March 12, 2020 by manterola

[Nezgar]

1 minute ago, manterola said:

I did not invested in a real eprom eraser, I just got a cheap toothbrush sanitizer...

Wow... who would have thought.

 

2 hours ago, unixdude said:

Now it's just finding the chips, and I am now consulting datasheets and the supported chip list to ensure that the ones I buy are supported.

Some examples of sources on eBay, all of which are approx $10 or less for 10, shipping included:

 

EPROM 27C32: https://www.ebay.com/itm/392628656812

EPROM 27C64: https://www.ebay.com/itm/281708681559
EEPROM 28C64: https://www.ebay.com/itm/202842348173

EPROM 27C128: https://www.ebay.com/itm/281133889596

EPROM 27C256: https://www.ebay.com/itm/280867704856
EEPROM 28C256: https://www.ebay.ca/itm/273229216404

EPROM 27C512: https://www.ebay.com/itm/281331692364
EEPROM 27C512: https://www.ebay.com/itm/162776471629

 

EEPROM's are less "Retro" compared to the UV EPROM's, but the TL866 can electronically erase EEPROMs with a click instead of waiting for UV erase, great for testing, but faster access times of these can cause some instability as an OS ROM in some systems, so probably not recommended for permanent installation, or a chip going into a machine for someone else.

[Nezgar]

30 minutes ago, manterola said:

I would like to program and read the P8050AH intel chips use in the xf551 and clones. for example I would like to extract the FW of my original XF551 which actually worked pretty well. The info is very limited regarding this processor(with included memory),they called this family  the MCS48 something like that. 

Can we MacGyver  TL866 to program those maybe?

The P8050 itself isn't listed in the TL866 II supported device list, and even though this chip supposedly has 4K of ROM, I don't think the XF551 uses it.

 

The ROM of an XF551 is a separate socketed 2764-compatible mask ROM, can be read out as such with a programmer, and replaced with a 27C64 EPROM programmed with the same with no modification. The the lower 4KB of the 8KB original ROM contains the data, and the higher 4KB is all zeros. If a replacement OS such as Hyper-XF is programmed the the upper 4KB, A switch could be installed on the highest address line to select between the original, and HyperXF ROM banks.

[manterola]

Yep, you are right , however my xf551 came with the intel 8050 only (not a generic one, it has an intel 8050 with Atari C0 number). The FW is IN the Atari/Intel 8050. Last year I got another Xf551 which it came with FW in a separate chip, and this one indeed has problems when changing densities. So since then I been thinking in how to get the Original FW from my original XF551 (from the intel 8050 chip) so I can compare and see which FW it had.

So Atari used the intel 8050 in both ways: with and without the external eprom. My guess is that every atari branded intel 8050 comes with the FW already there, but setting one pin low (or high) they choose not to use it and use the FW in the eprom instead.

So anyway, just random interesting stuff without a real practical use, just the coolness of running my xf551 as before without the need of EPROM.

BTW, thanks Nezgar for recommending the TL866 many months ago. It is a lot of fun to have a programmer at home. I have learned a bit since then regarding these EPROM matters, that is why I asked about the MacGyver it to make it work with other chips not directly supported. Thanks again

Edited March 12, 2020 by manterola

[unixdude]

Well, I'm on my way: I have ordered 5x 27C128 EPROMs, a TL866II+ burner, and an eraser.  I should have all of this by ... wait for it... May 27. Hopefully much sooner than that. In any case, until that comes I will be playing with my 5200; after all of this arrives, I'll work on my 600XL and 800XL again.

[+kheller2]

6 hours ago, manterola said:

Yep, you are right , however my xf551 came with the intel 8050 only (not a generic one, it has an intel 8050 with Atari C0 number). The FW is IN the Atari/Intel 8050. Last year I got another Xf551 which it came with FW in a separate chip, and this one indeed has problems when changing densities. So since then I been thinking in how to get the Original FW from my original XF551 (from the intel 8050 chip) so I can compare and see which FW it had.

So Atari used the intel 8050 in both ways: with and without the external eprom. My guess is that every atari branded intel 8050 comes with the FW already there, but setting one pin low (or high) they choose not to use it and use the FW in the eprom instead.

 

This is news to me.  I didn't think Atari released the XF w/o a separate FW chip.  Can anyone else chime in here and confirm that indeed there are XFs w/o a ROM chip? Note that there are two versions of the XF board, and two versions of the drive mech (each with their own pros and cons).   Density switching is a typical XF complaint.

[manterola]

30 minutes ago, kheller2 said:

This is news to me.  I didn't think Atari released the XF w/o a separate FW chip.  Can anyone else chime in here and confirm that indeed there are XFs w/o a ROM chip? Note that there are two versions of the XF board, and two versions of the drive mech (each with their own pros and cons).   Density switching is a typical XF complaint.

!?