Atari 2600 Cartridge/ eprom help

[petik1]

Hi all, I'm new to the forums, but I've been lurking for a while. I've got a copy of pitfall (4K PCB I assume) and an eeprom thats over 4k. I removed the chip and added a socket. If I burn a 4K game, say Halo 2600, would it function correctly? Thanks in advance.

Edited August 5, 2010 by petik1

[GroovyBee]

If I burn a 4K game, say Halo 2600, would it function correctly?

 

No! You'll need an inverter between address line A12 and the EPROM's Chip Enable CE (active low) signal. The EPROM's Output Enable OE signal should be connected to GND. You'll also need to pull unused address lines to ground or double up the binary image in the EPROM.

[petik1]

If I burn a 4K game, say Halo 2600, would it function correctly?

 

No! You'll need an inverter between address line A12 and the EPROM's Chip Enable CE (active low) signal. The EPROM's Output Enable OE signal should be connected to GND. You'll also need to pull unused address lines to ground or double up the binary image in the EPROM.

 

OK. I have no clue what that means. If I could get a pinout that would help. What do you mean by "you'll also need to pull unused address lines to ground." And Inverter? Also, not knowing this beforehand, I burned an 8K ROM and used it on a 4K board not knowing it was a 4K board without the inverter and all of that. Is it still usable? If it helps, I've got this chip My link Thanks.

Edited August 5, 2010 by petik1

[GroovyBee]

So you want to burn a 4K game into a 2K SOIC part and fit it into a .1" pitch DIL socket? Makes no sense to me.

[petik1]

So you want to burn a 4K game into a 2K SOIC part and fit it into a .1" pitch DIL socket? Makes no sense to me.

I mightve posted the wrong part. Its a 16k onsemi eeprom with .6 spacing. The chip and socket are fine, if a 16k is suitable, then I just need to know the pinout of the chip and the board. Edited August 5, 2010 by petik1

[Wickeycolumbus]

So you want to burn a 4K game into a 2K SOIC part and fit it into a .1" pitch DIL socket? Makes no sense to me.

I mightve posted the wrong part. Its a 16k onsemi eeprom with .6 spacing. The chip and socket are fine, if a 16k is suitable, then I just need to know the pinout of the chip and the board.

 

I don't know about Activision, but Atari's mask ROMs have the same pinout as 2532s aside from being active high.

[+batari]

So you want to burn a 4K game into a 2K SOIC part and fit it into a .1" pitch DIL socket? Makes no sense to me.

I mightve posted the wrong part. Its a 16k onsemi eeprom with .6 spacing. The chip and socket are fine, if a 16k is suitable, then I just need to know the pinout of the chip and the board.

It's probably a 28c16 or similar, which is 16k bits not bytes. It's not big enough.

[petik1]

So you want to burn a 4K game into a 2K SOIC part and fit it into a .1" pitch DIL socket? Makes no sense to me.

I mightve posted the wrong part. Its a 16k onsemi eeprom with .6 spacing. The chip and socket are fine, if a 16k is suitable, then I just need to know the pinout of the chip and the board.

It's probably a 28c16 or similar, which is 16k bits not bytes. It's not big enough.

 

%$#)^#$^&$#) %^$&$)%&$%&$Y^#$&^) I didn't order the part. So the minimum size is a 32 kilobit? I'll have to ask the man who burned the eeprom a question, because he burned an 8 kilobyte game on there... Anyhow, once I have the correct chip, do I need anything else or can I just use it as it is?

Edited August 6, 2010 by petik1

[GroovyBee]

Anyhow, once I have the correct chip, do I need anything else or can I just use it as it is?

 

Nope! See post #2

[petik1]

Anyhow, once I have the correct chip, do I need anything else or can I just use it as it is?

 

Nope! See post #2

 

I got that, but what pins are the A12, CE, OE, and ground. I can't find a pinout. Also, what do you mean by "You'll also need to pull unused address lines to ground."

[GroovyBee]

I got that, but what pins are the A12, CE, OE, and ground. I can't find a pinout. Also, what do you mean by "You'll also need to pull unused address lines to ground."

 

A pin-out if what? The EPROM or the 2600 cart connector. For the EPROM find its datasheet on the web. For the cart connector have a look at the FAQ for the 2600.

[petik1]

Sorry, I had a hard time finding a suitable eprom. Is this good? eeprom

Also, which address lines are unused? And by inverter, did you mean a 7404 hex inverter?

[GroovyBee]

Is that the same EEPROM as the one you have? Why do you want to use an open collector device like the 74LS06? If you use that you'll need to add an external pull-up. You'd be better off with a 74LS04.

[petik1]

Honestly, im not experienced in this. Ill go with a 74ls04 if i can find it.

[tokumaru]

Also, what do you mean by "You'll also need to pull unused address lines to ground."

The address lines are used to tell the chip which address the console is trying to read. Each additional address line doubles the capacity of the chip (12 address lines can address 4KBytes, 13 lines can address 8KBytes, and so on), so if the game you are burning is smaller than the chip you are burning it to, you have to connect the unused higher address lines to GND, forcing the chip to never output data from the region where nothing was written to. This makes the chip look smaller than it actually is, since the unused parts will not be accessible.