how to use eprom in stead of basic rom

[Marius]

Hi.

 

I don't understand why this isn't working:

 

I burned a 2764 eprom. I rewired the 28 pin wires to the Right Ax and Dx lines of the BASIC pinout (like I see in the schematic).

 

But my atari keeps starting with selftest.

 

Is it possible anyway?

 

Is there another way of doing this?

 

And I don't know what to do with pin 20 of eprom (/CE) and pin 22 of eprom (/OE)

 

I connected/rewired /CE to /CS

and /OE too... but that did not work

/OE to GND did not work either

 

I really need to know it. So any help would be appreciated. Thanks!

 

Marius

[sloopy]

did you wire it up like this?

 

also good info.

 

 

(easier to search and link then type it all out again, especially when it was expressed so well...)

sloopy.

[+Larry]

There used to be a place where you could buy a small adapter that allowed just plugging the 2764 into the board and "presto." I think that a C64 guy did it and had something like 1000 "mini-boards" made up. Admittedly, this rewiring is not difficult, but plug-and-play is always nice.

 

But let's take this a step further -- how about a 27128 with both Basic and AsmEd in it - switchable. Can someone please show the wiring for that?

 

-Larry

 

 

did you wire it up like this?

 

also good info.

 

(easier to search and link then type it all out again, especially when it was expressed so well...)

sloopy.

[Marius]

@Sloopy

 

Thank you SO MUCH! I tried the search function (again), but for some reason I did not found those topics. Great help indeed. Strange BTW that in the schematic BASIC Pin 20 (/CS) is connected to ground. In my wiring (and in the description in that other topic /CE is connected to /OE). Anyway I did the last one, and that worked.

 

@ Larry,

 

That was just wat I wanted to do, but first I wanted to test it with a 2764.

 

Making that other thing is not that hard anymore. When you put a basic and assembler editor rom (both 8K) in a 16K eprom (27128) you have to put a switch + resistor on pin 26 of the eprom.

 

When you switch A13 (pin 26) to ground the rom is using the first 8KB (0000-2FFF).

When you switch A13 (pin 26) to +5V the rom is using the next 8kb (3000 - 4fff)

 

this is what you do: take a switch with three legs.

 

The right leg is connected with a wire to ground (VSS)

The left leg is unused

the center leg = connected to pin 26 of eprom 27128

 

Pin 26 is also connected to one side of a resistor (4k7 is a good one) and the other side of the resistor is connected to +5V (VCC)

 

 

 

 

This should work. I did NOT test it yet, but i'm 99.99% sure this will work. I'm not responsible for any damage

 

It's the same way two OS'ses are switched in a 27C256. only then it is with pin 27 (A14) in stead of pin 26.

 

Have fun!

Marius

[russg]

Hi.

 

I don't understand why this isn't working:

 

I burned a 2764 eprom. I rewired the 28 pin wires to the Right Ax and Dx lines of the BASIC pinout (like I see in the schematic).

 

But my atari keeps starting with selftest.

 

Is it possible anyway?

 

Is there another way of doing this?

 

And I don't know what to do with pin 20 of eprom (/CE) and pin 22 of eprom (/OE)

 

I connected/rewired /CE to /CS

and /OE too... but that did not work

/OE to GND did not work either

 

I really need to know it. So any help would be appreciated. Thanks!

 

Marius

Know nothing about burning EPROMs. Is your OS one that boots without BASIC? Or, if you are booting holding the OPTION, it will boot to disk or self test. Pardon if this is obvious.

[+bob1200xl]

If you get to Self-Test, something has to be working in your OS. If your BASIC ROM is causing an OS failure, it must be jumping on the buss at the wrong times. If you hold down OPTION, does the OS come up OK? (boot from disk?) Does it work if you use an external cart?

 

The EPROM CS and OE are wired together. No reason to do it any other way. Do you have a really slow EPROM? Grounding CS didn't fix the problem, it just skewed it enough so the system does not fail. Not good...

 

What is this in?

 

Bob

 

 

 

Hi.

 

I don't understand why this isn't working:

 

I burned a 2764 eprom. I rewired the 28 pin wires to the Right Ax and Dx lines of the BASIC pinout (like I see in the schematic).

 

But my atari keeps starting with selftest.

 

Is it possible anyway?

 

Is there another way of doing this?

 

And I don't know what to do with pin 20 of eprom (/CE) and pin 22 of eprom (/OE)

 

I connected/rewired /CE to /CS

and /OE too... but that did not work

/OE to GND did not work either

 

I really need to know it. So any help would be appreciated. Thanks!

 

Marius

[sloopy]

There used to be a place where you could buy a small adapter that allowed just plugging the 2764 into the board and "presto." I think that a C64 guy did it and had something like 1000 "mini-boards" made up. Admittedly, this rewiring is not difficult, but plug-and-play is always nice.

 

But let's take this a step further -- how about a 27128 with both Basic and AsmEd in it - switchable. Can someone please show the wiring for that?

 

-Larry

 

 

did you wire it up like this?

 

also good info.

 

(easier to search and link then type it all out again, especially when it was expressed so well...)

sloopy.

 

 

you are looking for Jim Brain's Go 4 Retro site, he even expanded the adaptor to be able to use up to 27512's...

 

he is a good guy (even if he does use that 'C' stuff ;'), and i have ordered stuff from him several times, and only sells A quality products...

 

sloopy.

Edited February 27, 2011 by sloopy

[russg]

Hi.

 

I don't understand why this isn't working:

 

I burned a 2764 eprom. I rewired the 28 pin wires to the Right Ax and Dx lines of the BASIC pinout (like I see in the schematic).

 

But my atari keeps starting with selftest.

 

Is it possible anyway?

 

Is there another way of doing this?

 

And I don't know what to do with pin 20 of eprom (/CE) and pin 22 of eprom (/OE)

 

I connected/rewired /CE to /CS

and /OE too... but that did not work

/OE to GND did not work either

 

I really need to know it. So any help would be appreciated. Thanks!

 

Marius

Know nothing about burning EPROMs. Is your OS one that boots without BASIC? Or, if you are booting holding the OPTION, it will boot to disk or self test. Pardon if this is obvious.

Ah, well, I display my ignorance. BASIC cart should come up whether OPTION or not, it should go to cart.

[Marius]

In case it was not clear already:

 

Problem is fixed. Thanks to info provided in the top of the thread.

 

My fault btw was not something with /OE and /CS. The problem was that I did not put +5 on /PGM and VPP. I thought I had to leave those pins alone, but I was wrong.

 

Now it works perfect.

 

I want to build in Basic C and Assembler Editor inside my Atari. A switch on the back of the atari gives me the possibility to change rom.

 

Only problem left is that I found out now that Assembler Editor is SLOW (waaaah). I thought: I can live without macro's... but this speed is terrible.

 

Mac/65 is so much faster... it is lightning fast compared to Assembler Editor.

 

Unfortunately Mac/65 has to be build in a OSS Super Cart. I found information about it, but I don't see myself building such a thing.

 

So I stick with the disk version... or perhaps I buy myself another 1Mbit flash cart from AtariMax.

 

Anyway: thanks for all your help folks!

Marius

[Rybags]

AsmEd is useless for anything serious or bigger than 100 lines or so.

 

But the debugger is really good for testing stuff out. I never really much liked the Mac-65 DDT way of doing things.

I prefer to have the "history" of stuff you've changed/displayed etc. left behind and doing it via E: means you can keep relevant stuff onscreen.

[+David_P]

Poking around the Retro Innovations site, there are other interesting things - like the ROM-el 2364, that gives you as 128KB flash device in place of a 2364, so you could have 16 different 8k carts in place of BASIC (you'd need 4 switches for ROM selection). Alternatively, install it in a 16K Atari cartrisdge with a single jumper and 3 switches, and choose from 8 different 16K (non bank selecting) games.

 

http://store.go4retro.com/products/ROM%252del-2364-FLASH-ROM-Replacement.html

[+Larry]

I purchased one of the 2364 adapters and installed it in an 800XL, using a common 27C64. "Plug and Play" -- works great.

http://store.go4retro.com/products/2364-Adapter.html (also shown above in post #7). When you go to this link, the pic/price is for bare board only. I found a post of the Commodore 2364 Rom pinout and it appeared identical to the pinout of our Atari. Thought it would be good to check.

 

I also have a 4-in-1 OS in this computer so it is a snug fit, but works fine using a tall socket or two sockets stacked for the OS. (Not my first choice, but I don't see any reasonable way around it.)

 

It looks to me like using a 27128 -- 27512 would be no problem, except that I'm not sure yet how to wire those using the provided connections on the adapter board. No docs come with this, so I'm trying to find out more, or one of our better tech folks will need to take a look.

 

Note that there are what looks like to be 1/8 watt resistors on the board, and those may be to replace the resistors on the switches for the bigger eproms. (?) Possibly, one could use the board alone (no adapter) to make the wiring of a 4-in-1 a little cleaner with no bent pins and resistors soldered to the pins. (?)

 

Final note. Don't know about compatibility or need for this if you install one of Candle's "ultimate 1 MB upgrades" ???

 

-Larry

[sloopy]

I purchased one of the 2364 adapters and installed it in an 800XL, using a common 27C64. "Plug and Play" -- works great.

http://store.go4retro.com/products/2364-Adapter.html (also shown above in post #7). When you go to this link, the pic/price is for bare board only. I found a post of the Commodore 2364 Rom pinout and it appeared identical to the pinout of our Atari. Thought it would be good to check.

 

I also have a 4-in-1 OS in this computer so it is a snug fit, but works fine using a tall socket or two sockets stacked for the OS. (Not my first choice, but I don't see any reasonable way around it.)

 

It looks to me like using a 27128 -- 27512 would be no problem, except that I'm not sure yet how to wire those using the provided connections on the adapter board. No docs come with this, so I'm trying to find out more, or one of our better tech folks will need to take a look.

 

Note that there are what looks like to be 1/8 watt resistors on the board, and those may be to replace the resistors on the switches for the bigger eproms. (?) Possibly, one could use the board alone (no adapter) to make the wiring of a 4-in-1 a little cleaner with no bent pins and resistors soldered to the pins. (?)

 

Final note. Don't know about compatibility or need for this if you install one of Candle's "ultimate 1 MB upgrades" ???

 

-Larry

 

 

i have several of these... i have other things from jim in my C= equipment... at work we are replacing the servers, so my time is limited... but when i get time, i will be making a How-To for various things...

 

also i have mentioned Brains site before but seems people didnt really look at it before... he has alot of good stuff...

 

sloopy.

[BillC]

I purchased one of the 2364 adapters and installed it in an 800XL, using a common 27C64. "Plug and Play" -- works great.

http://store.go4retro.com/products/2364-Adapter.html (also shown above in post #7). When you go to this link, the pic/price is for bare board only. I found a post of the Commodore 2364 Rom pinout and it appeared identical to the pinout of our Atari. Thought it would be good to check.

 

I also have a 4-in-1 OS in this computer so it is a snug fit, but works fine using a tall socket or two sockets stacked for the OS. (Not my first choice, but I don't see any reasonable way around it.)

 

It looks to me like using a 27128 -- 27512 would be no problem, except that I'm not sure yet how to wire those using the provided connections on the adapter board. No docs come with this, so I'm trying to find out more, or one of our better tech folks will need to take a look.

 

Note that there are what looks like to be 1/8 watt resistors on the board, and those may be to replace the resistors on the switches for the bigger eproms. (?) Possibly, one could use the board alone (no adapter) to make the wiring of a 4-in-1 a little cleaner with no bent pins and resistors soldered to the pins. (?)

 

Final note. Don't know about compatibility or need for this if you install one of Candle's "ultimate 1 MB upgrades" ???

 

-Larry

This adapter pulls A13/A14/A15 of the 27512 compatible socket high through the resistors and provides connection points, all other signals are routed to the correct pin of the 2364 header. You just connect wires/switches to the 4 pads and ground A13/A14/A15 as desired to select which 8K bank you wish to access.

 

The "Ultimate" upgrade already contains space for 1 or 2(XEGS only) 8K cartridge images, I don't believe it will be able to access the BASIC socket.

[+Larry]

Thanks Sloopy and BillC!

 

@Sloopy-

 

I've never seen a "standoff socket" like this before. (At least I think that the lower socket and the "extender pins" are one piece.) Any idea what these are called? I'm assuming that the pins are not just pressed into the lower socket.

 

-Larry

[sloopy]

Thanks Sloopy and BillC!

 

@Sloopy-

 

I've never seen a "standoff socket" like this before. (At least I think that the lower socket and the "extender pins" are one piece. Any idea what these are called? I'm assuming that the pins are not just pressed into the lower socket.

 

-Larry

 

 

its a DIP header socket...

 

http://urql.com/vntm

 

sloopy.

[+Stephen]

Thanks Sloopy and BillC!

 

@Sloopy-

 

I've never seen a "standoff socket" like this before. (At least I think that the lower socket and the "extender pins" are one piece. Any idea what these are called? I'm assuming that the pins are not just pressed into the lower socket.

 

-Larry

 

 

its a DIP header socket...

 

http://urql.com/vntm

 

sloopy.

Hmm - learn something new every day.

[+bob1200xl]

Atari uses the same type of header in the 810 analog board. This type of header makes it easy to maintain pin alignment, as opposed to strip headers which must be soldered in place while being held in alignment (plugged into a socket or some such). Of course, the socket header is really designed for a particular pin count, 40-pin, 28-pin, 16-pin, etc, where the strip headers can be snapped off in any size - from 8 to 40 pins.

 

Bob

 

Thanks Sloopy and BillC!

 

@Sloopy-

 

I've never seen a "standoff socket" like this before. (At least I think that the lower socket and the "extender pins" are one piece. Any idea what these are called? I'm assuming that the pins are not just pressed into the lower socket.

 

-Larry

 

 

its a DIP header socket...

 

http://urql.com/vntm

 

sloopy.

Hmm - learn something new every day.

[brain]

Pin headers will ruin leaf IC sockets, and will not fit in machine pin IC sockets.

 

On the 2364 Adapter, there are 4 holes on the side of the adapter. By attaching wires to the holes, and attaching 3 switches to A13/A14/A15 and running the other end of each switch to the ground wire, you can select one of 8 8kB "banks" of the EPROM.

 

Jim

[sloopy]

Pin headers will ruin leaf IC sockets, and will not fit in machine pin IC sockets.

 

On the 2364 Adapter, there are 4 holes on the side of the adapter. By attaching wires to the holes, and attaching 3 switches to A13/A14/A15 and running the other end of each switch to the ground wire, you can select one of 8 8kB "banks" of the EPROM.

 

Jim

 

 

Hey Jim, odd to see you in these parts :')

 

sloopy.

[BillC]

Pin headers will ruin leaf IC sockets, and will not fit in machine pin IC sockets.

 

On the 2364 Adapter, there are 4 holes on the side of the adapter. By attaching wires to the holes, and attaching 3 switches to A13/A14/A15 and running the other end of each switch to the ground wire, you can select one of 8 8kB "banks" of the EPROM.

 

Jim

Whether or not a header will damage a leaf socket or fail to fit in a machine pin socket depends on the size of the pin. The machine pin sockets I checked accept .015" to .025" diameter pins, or .010" to .018" square pins.

 

Headers with .025" square posts are only meant for soldering to the circuit board and connecting cables, headers meant for use with sockets normally have .018" diameter pins.

[brain]

Whether or not a header will damage a leaf socket or fail to fit in a machine pin socket depends on the size of the pin. The machine pin sockets I checked accept .015" to .025" diameter pins, or .010" to .018" square pins.

I was not specific enough. square post headers (the cheapest and most common) will ruin leaf sockets.

Headers with .025" square posts are only meant for soldering to the circuit board and connecting cables, headers meant for use with sockets normally have .018" diameter pins.

Correct, but I tend to discourage any headers, because the nuance of machine pin versus square pin is tough to get across, and inevitably the wrong one will be selected by the person asking.

 

So, in essence, if you need to ask me what strip header to use, I am going to say none. :-)

 

Jim