Amiga.org

Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: AltRN8 on December 06, 2017, 01:32:24 AM

Title: Can I use these for 1MB A4000 Custom Kickstart
Post by: AltRN8 on December 06, 2017, 01:32:24 AM: I'm trying to build a custom 1MB kickstart for my A4000. I have the ROMY board installed so I should be able to use the large size. I'm getting confused on the EPROM details. Was hoping someone could confirm that I could use the following:

https://www.ebay.com/itm/10pcs-AMD-27C400-AM27C400-120DC-UV-EPROM-DIP-40/281626929244?hash=item419245e85c:g:kgwAAOSwu-BWQvgw

Thanks.
Title: Re: Can I use these for 1MB A4000 Custom Kickstart
Post by: Whaka on December 06, 2017, 04:33:27 AM: 27C400 are 256Kb x 16 bit, so no, you can't for this use.
you need 512 x 16. maybe the 27C800, but wait for others confirmation as i'm not really sure :)

edit : i checked pinout, you can go for 27C800.
Title: Re: Can I use these for 1MB A4000 Custom Kickstart
Post by: SpeedGeek on December 06, 2017, 03:20:04 PM: Quote from: Whaka;833836
27C400 are 256Kb x 16 bit, so no, you can't for this use.
you need 512 x 16. maybe the 27C800, but wait for others confirmation as i'm not really sure :)

edit : i checked pinout, you can go for 27C800.

WRONG! The A4000 has 2 ROM sockets so 256KB x 16 x 2 = 1MB! :rtfm:
Title: Re: Can I use these for 1MB A4000 Custom Kickstart
Post by: SpaceMonkey on December 06, 2017, 06:43:26 PM: **** Helps if I fully read the first post
Title: Re: Can I use these for 1MB A4000 Custom Kickstart
Post by: Jeff on December 06, 2017, 06:57:27 PM: I have an A4000D and a ROMY too. I am also having trouble creating a working 1 meg Rom. I'll be interested if you get yours working. I have a Willem programmer, UV eraser, and plenty of blank 27C400's waiting.
Title: Re: Can I use these for 1MB A4000 Custom Kickstart
Post by: Whaka on December 06, 2017, 07:37:53 PM: Quote from: SpeedGeek;833847
WRONG! The A4000 has 2 ROM sockets so 256KB x 16 x 2 = 1MB! :rtfm:
okay... so i miss something somewhere :D
just to be sure, and clear :

256 Kilobit x 16 bit = 4096 Kilobit/8 bit = 512 Kilobyte ?
Title: Re: Can I use these for 1MB A4000 Custom Kickstart
Post by: LoadWB on December 06, 2017, 07:46:24 PM: Interested, as well. I have some Winbond W29C040 (and proper ROMs) which I would like to use for a custom 1MB Kickstart, but I just do not have the time tinker.
Title: Re: Can I use these for 1MB A4000 Custom Kickstart
Post by: Chucky on December 06, 2017, 07:46:28 PM: 27c400 can contain 512Kilobytes of data..

so 27C400 is what you need.. YES!..

that is what I have used.. 27C800 when doing a kickstartswitch
Title: Re: Can I use these for 1MB A4000 Custom Kickstart
Post by: Jeff on December 06, 2017, 09:45:33 PM: I would guess that it is best to create the 1 meg Kickstart as 1 file to test with WinUAE? Then split and swap to burn eproms?

For the purpose of testing will the A4000 boot with the ROMY installed and the original 512k Kickstart chips?
Title: Re: Can I use these for 1MB A4000 Custom Kickstart
Post by: Chucky on December 06, 2017, 09:50:31 PM: I always testin UAE..

and yes. it works fine with romy and 512k rom
Title: Re: Can I use these for 1MB A4000 Custom Kickstart
Post by: AltRN8 on December 07, 2017, 12:41:29 AM: Thanks!
Title: Re: Can I use these for 1MB A4000 Custom Kickstart
Post by: AltRN8 on December 07, 2017, 12:42:35 AM: I'll be sure to post results after I get the chips and work through the process. I've put off doing this for too long and I am dying to finally get this working. I'm also looking to use an 060 via one of the adapter boards so I need the 060 libraries in rom to get this to work.
Title: Re: Can I use these for 1MB A4000 Custom Kickstart
Post by: Chucky on December 07, 2017, 06:13:14 AM: Quote from: AltRN8;833864
I'll be sure to post results after I get the chips and work through the process. I've put off doing this for too long and I am dying to finally get this working. I'm also looking to use an 060 via one of the adapter boards so I need the 060 libraries in rom to get this to work.

060 libs are NOT romable.. it is a patch in the kickstart that disables the FPU.. nothing more.. (so it will not crash at startup)

libs will still be needed in libs:
Title: Re: Can I use these for 1MB A4000 Custom Kickstart
Post by: AltRN8 on December 07, 2017, 10:41:10 PM: Thanks for the response I wouldn't want to spread misinformation. I actually would have done as you suggested. I have directions written down of what needs to be done I just misremembered. I'll chalk it up to the ignorance of inexperience. Anyway thanks again for the correction.