Burning my own TOS Chips

[Colleton]

I'd like to be able to burn my own TOS chips, but need some advice to get started.

 

I'm looking at the TL866II Plus USB Programmer as the burner, but what software do I use to control it?

What EEPROMS do I need, and where can I buy them?

 

Any and all advice/help would be appreciated.  Thanks!

[snarkdluG]

The programming tool is called xgpro.

 

eprom depends on which Atari you are planning to upgrade. Diffrent TOS version has different sizes and demands different eprom. Normal STfm for example can use 6 or 2 eprom configuration. 6 is easier since the eprom just fits. 2 eprom you need to hardware hack a bit to get them to work since the eprom is 32 pin and the slots is 28 pins. There is no 28 pin of that memory size that is a direct fit. Depending of what you choose and what is fitted already you might have to change some solder blobs on the main board. And fitting a chip in certain cases. STE often needs to change some 0 ohms resistors, other then that rather simple. 

 

Then you can choose from eprom or eeprom chips. The eprom is a bit cheaper but needs UV light (sun or gadget) to be erased if you want to program it again. eeprom is electrically erasable memory and you don't need additional hardware.

 

So what Atari do you got and have you open it up and looked what configuration it has now? Pics please!

 

EDIT: Is it your Mega 2 you want to upgrade?

Edited May 5, 2020 by snarkdluG

[Colleton]

Thanks for the reply!

 

No, it isn't the Mega 2. I've already installed TOS 1.04 that I bought from B&C on eBay in the Mega 2.

 

I'm looking at picking up another 520 ST, and I thought it would be a good time to learn how to burn my own ROMS instead of buying them from someone else.  This being the case, it'll be a 6 chip set of 1.04.  So a 2764 of some sort would be the correct prom?  Is buying from eBay a good choice?

[snarkdluG]

A rom is 192Kbyte on the ST, or TOS 1.00-TOS 1.04 is. So 27C256/29C256 or similar work. 256Kbit/8 = 32 Kbyte and 6 of them = 192 Kbyte. I think 150ns or faster is fine. Can't remember what Atari put in. I say get 100ns or faster.

 

eBay... Well, most of the time it is fine. To be safe, buy one or two extra. Just verify when you burn them that they burnt correctly. It's a gamble. 

 

EDIT: Apparently 200ns is fine and 150ns or faster chip is prefer. 

Edited May 5, 2020 by snarkdluG

[tjlazer]

I have a cheap Chinese Willem burner and get chips on eBay.  Works fine.  You have to have the correct images to burn though.  And there are tools on the ST that can  help you split a TOS image into the 6 files.

[Colleton]

1 hour ago, tjlazer said:

You have to have the correct images to burn though.

 

Okay, this is interesting.  I have different versions of TOS in *.img format.  What format do they need to be in?

 

My thanks to you and snarkdluG for helping me with this.  I'm as ignorant about this as it is possible to be.

[tjlazer]

1 hour ago, Colleton said:

 

Okay, this is interesting.  I have different versions of TOS in *.img format.  What format do they need to be in?

 

My thanks to you and snarkdluG for helping me with this.  I'm as ignorant about this as it is possible to be.

They need to be properly split into 6 different files or it won't work.

 

Here is a thread I started in 2006 when I went down the same path you are going down now!
 

 

[Colleton]

Awesome, thank you!

[Colleton]

Okay, after reading through the other thread, I downloaded Peter's Romsplit program.  There may have been an easier way to accomplish this, but here's what I did:

 

1. Got Romsplit and the 1.04 image file I wanted to split transferred to my ST HDD.

2. Split the image file into 6 files.

3. Copied the new rom files to a blank .st file loaded on my Gotek.

4. Using Steem, copied the split files out of the .st file onto my PC HD.

 

I now have 6 32K files with the following file extensions: *.HI0, *.HI1, *.HI2, *.LO0, *.LO1, *.LO2

 

So, I could now burn these to 27C256/29C256 eproms using a TL866II and hopefully be good to go?

Edited May 6, 2020 by Colleton

[+tf_hh]

16 hours ago, Colleton said:

I now have 6 32K files with the following file extensions: *.HI0, *.HI1, *.HI2, *.LO0, *.LO1, *.LO2

 

So, I could now burn these to 27C256/29C256 eproms using a TL866II and hopefully be good to go?

 

Sounds good - go ahead 👍

[Colleton]

3 minutes ago, tf_hh said:

Sounds good - go ahead 👍

 

Thanks, waiting on the TL866II  and eproms to arrive.

[Colleton]

Thanks to everyone for their help with this.  Received everything today, and it all worked the 1st time. I've burned a full set of 6 TOS 1.04 roms and have them installed and working in a 520ST with a US HD.  Very cool!

 

The chips I bought were TI TMS27C256.  They were already programmed and had to be erased, but were in very good condition.  I paid $12 for 10 eproms.  Too much, or is that okay?  I erased the chips for 12 minutes in the eprom eraser, is that a reasonable amount of time?  That came from a youtube video that I'd watched.

 

Using the xgpro software was fairly intuitive, or maybe I got lucky.  I selected the chip type, then blank checked, programmed and verified each chip using the files I'd generated with romsplit.

[guus.assmann]

Hello,

 

The fact that you succeded is proof that you did it right.

 

And the price for the chips is quite good I think.

In future, also look at the speed of the chips. 150nS is mostly good enough. (On 8Mhz system 200nS will also do)

On a TT you may want to use 120nS.

 

Erasing depends on the light source. Just experiment with shorter times.

If you test before programming, it's ok.

 

One very important thing for erasing Eproms. Make sure they're in conducting foam,all pins must be electrically connected.

Failing to do so may destroy an Eprom. Especially the older ones like 2716 or 2732. The even older 2708 will definitivly not survive if pins are not connected.

I've learned that in the time that an Eprom costs FL 150 (Current equivalent is $ 150). They were not my Eproms, my manager killed them and I found out why.

 

BR/

Guus

[Colleton]

2 hours ago, guus.assmann said:

One very important thing for erasing Eproms. Make sure they're in conducting foam,all pins must be electrically connected.

Failing to do so may destroy an Eprom. Especially the older ones like 2716 or 2732. The even older 2708 will definitivly not survive if pins are not connected.

I've learned that in the time that an Eprom costs FL 150 (Current equivalent is $ 150). They were not my Eproms, my manager killed them and I found out why.

 

I had no idea, thanks!

[tjlazer]

$12 for 10 chips is a very good price.  It's usually 2-3 times that price.