EPROMS To Order?

[toddtmw]

So, I decided I wanted to upgrade the firmware in my Rana drive and needed a 2732 EPROM.

 

I was faced with the familiar option. Spend more to get something relatively fast or pay next to nothing but wait forever.

 

So, does anyone have a list of EPROMS I should just order to have on hand for 8-bit stuff?

 

I'd love to have a little stockpile of chips so I can do these types of projects on the spur of the moment without having to wait for an order.

 

Thanks!

[MrMartian]

2732s for peripheral ROMs, 27128 for OS roms.. Or 27256 and you can switch two of them, 27512, switch four of them...

 

I have a stash of ICT 27CX641 chips.. 8Kx8, 24 pin... Great for replacing BASIC roms and C64 roms... Don't know if you can still buy them anywhere though..

[toddtmw]

Thanks. Where do people buy from?

[xrbrevin]

fleabay is one resource

[toddtmw]

Just now, xrbrevin said:

fleabay is one resource

Yeah. It’s not a fun place to shop for multiple things. I’d rather pay a little more for a little more ... organized store. 

[R.Cade]

It's much easier to just buy a bunch of cheap Winbond or ATMEL W27C256 or W27C512 EEPROMS. They can be used in place of any 28 pin EPROM. Make or buy some cheap 28->24 pin adapters and you have everything covered. To make smaller ROMs you just have to duplicate the data up to the size of the EEPROM.

 

Plus, they can be instantly reprogrammed- no waiting to erase and having old programmers with funny voltages, etc.

 

Edited May 13, 2020 by R.Cade

[Colleton]

58 minutes ago, R.Cade said:

To make smaller ROMs you just have to duplicate the data up to the size of the EEPROM.

 

So I can use a W27C512 in place of a W27C256?  Both are 28 pin DIP chips. 

[toddtmw]

1 hour ago, R.Cade said:

It's much easier to just buy a bunch of cheap Winbond or ATMEL W27C256 or W27C512 EEPROMS. They can be used in place of any 28 pin EPROM. Make or buy some cheap 28->24 pin adapters and you have everything covered. To make smaller ROMs you just have to duplicate the data up to the size of the EEPROM.

 

Plus, they can be instantly reprogrammed- no waiting to erase and having old programmers with funny voltages, etc.

 

I’m having trouble finding 28 to 24 adapters. Is there a term I can search for to find it?

 

do the w27c512’s burn with the same eprom burner? How do you erase them?

 

thanks. 

[R.Cade]

5 minutes ago, toddtmw said:

I’m having trouble finding 28 to 24 adapters. Is there a term I can search for to find it?

 

do the w27c512’s burn with the same eprom burner? How do you erase them?

 

thanks. 

Jim Brain sells them (http://store.go4retro.com/2364-adapter/).

 

The burner just sends a signal to erase them during the programming process. Takes 2 seconds.

 

[+David_P]

You can also order (in sets of 3) 27128 -> 2364 adapter from OSH Park.  https://oshpark.com/shared_projects/MjBJtpCb

[Ralphy Rocket]

4 hours ago, R.Cade said:

It's much easier to just buy a bunch of cheap Winbond or ATMEL W27C256 or W27C512 EEPROMS. They can be used in place of any 28 pin EPROM. Make or buy some cheap 28->24 pin adapters and you have everything covered. To make smaller ROMs you just have to duplicate the data up to the size of the EEPROM.

 

Plus, they can be instantly reprogrammed- no waiting to erase and having old programmers with funny voltages, etc.

 

Hi. Thanks Great Information! what speed should I be looking for??

 

Thanks