Search found 6 matches

by tbug
Thu Sep 16, 2021 1:55 am
Forum: Z88
Topic: 512K flash memory internal upgrade - no traces cut
Replies: 18
Views: 18609

Re: 512K flash memory internal upgrade - no traces cut

You're absolutely right of course and I apologise for making you go over your post again. I got confused by your photos when tracing the wire paths - I should have checked more carefully. Well, I've spent hours today trying to get my Z88 to recognise my internal 512KB FLASH ROM and have contact trac...
by tbug
Wed Sep 15, 2021 6:31 pm
Forum: Z88
Topic: 512K flash memory internal upgrade - no traces cut
Replies: 18
Views: 18609

Re: 512K flash memory internal upgrade - no traces cut

The OZ ROM is 512KB for internal ROM upgrade (to fill the full size of the 512K ROM chip). Only 256KB of that is the OS though, the other 256KB is a file store. Patters states his ROM was flashed by someone else, presumably using a PC Flash programmer but the subsequent upgrade was done by the Z88. ...
by tbug
Wed Sep 15, 2021 5:58 pm
Forum: Z88
Topic: 512K flash memory internal upgrade - no traces cut
Replies: 18
Views: 18609

Re: 512K flash memory internal upgrade - no traces cut

So how does that apply to this mod? Evidently the OZ upgrade from 4.7 to 5.0 worked for patters yet his ROM A17 is attached to motherboard A18.
by tbug
Wed Sep 15, 2021 5:45 pm
Forum: Z88
Topic: 512K flash memory internal upgrade - no traces cut
Replies: 18
Views: 18609

Re: 512K flash memory internal upgrade - no traces cut

Thanks Paul for the clarification. So does that mean that all the address lines could be mixed up and swapped and the software wouldn't care either way? It would just mean that a low HEX address would not necessarily live in the low section of the chip?
by tbug
Wed Sep 15, 2021 5:15 pm
Forum: Z88
Topic: 512K flash memory internal upgrade - no traces cut
Replies: 18
Views: 18609

Re: 512K flash memory internal upgrade - no traces cut

Sorry to barge in here but something doesn't seem right. Please correct me if I am wrong (and I often am) but I believe you have your wires crossed; literally! I did the internal upgrade (without cut traces by bending chip pins) on my Z88 around 3-4 years ago using NOS AM29F040B-90PC flash and HM628...
by tbug
Wed Sep 15, 2021 4:38 pm
Forum: Welcome Area
Topic: Greetings from north of the wall.
Replies: 0
Views: 1279

Greetings from north of the wall.

Hi folks, I've just joined and hope to participate in the Z88 forum mainly. Like you all, I have a love of all things 8-bit. First home micro I remember from primary school was either a ZX81 or Spectrum 16k in ~'83. Cut my teeth on the Acorn Electron ~ '85 to '87, sold my Star Wars toys to fund purc...