Potential changes on a future board.

Topic for users to share their building progress.
User avatar
exxos
Site Admin
Site Admin
Posts: 23496
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: Potential changes on a future board.

Post by exxos »

@PhilC We cannot off take the on-board ROM, because how are you supposed to boot the machine to program flashy when the flash has zero contents ?
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
User avatar
PhilC
Moderator
Moderator
Posts: 6016
Joined: Fri Mar 23, 2018 8:22 pm

Re: Potential changes on a future board.

Post by PhilC »

exxos wrote: Wed May 20, 2020 8:21 pm @PhilC We cannot off take the on-board ROM, because how are you supposed to boot the machine to program flashy when the flash has zero contents ?
No hadnt thought of that :oops:

Rom header then perhaps? Meaning you have a choice of rom types? Was just thinking about the costs of OTP roms as well btw, whereas 27c400 or 2 x 27c010 are cheap as chips?
If it ain't broke, test it to Destruction.
User avatar
exxos
Site Admin
Site Admin
Posts: 23496
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: Potential changes on a future board.

Post by exxos »

PhilC wrote: Wed May 20, 2020 8:28 pm No hadnt thought of that :oops:

Rom header then perhaps? Meaning you have a choice of rom types? Was just thinking about the costs of OTP roms as well btw, whereas 27c400 or 2 x 27c010 are cheap as chips?
So DIP rom's... Won't happen because..

1) We would have to do a lot of rerouting on the board and they take up a lot more space..
2) In terms of programming, it is far more annoying to program 2 chips as opposed to a single one.
3) in terms of myself producing these boards, I would also have to buy another part and stock it.. So instead of 100 ROM's, I'd have to stock 200.
4) as far as I know, DIP ROM's are not available in 55ns versions. 55ns will be needed for 32MHz operation.
5) It would also require twice as many sockets, aside from the costs, it is more soldering.

EDIT

So mouser have

AT27C020-55PU for £2.81 x 2 = £5.62
AT27C4096-55JU-T for £5.45

So DIP ROM Based on that would do nothing but take up another socket add more soldering and take more board space.

If you buy second hand stuff off evil bay and don't want to run fast-rom, I still don't think is worthwhile as you still need more sockets in more soldering.. In terms of a production environment, I would not use second-hand parts anyway.

IMHO I think going back to 2 DIP ROM's it is one huge step backwards.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
User avatar
PhilC
Moderator
Moderator
Posts: 6016
Joined: Fri Mar 23, 2018 8:22 pm

Re: Potential changes on a future board.

Post by PhilC »

27c4096 it is then :lol: :P
If it ain't broke, test it to Destruction.
User avatar
PaulJ
Posts: 1568
Joined: Sun Apr 08, 2018 1:14 am
Location: USA

Re: Potential changes on a future board.

Post by PaulJ »

If you want dip eprom just make an adaptor that plugs into the 68000 socket. Best of both worlds. :) Use the 27c400 as it has a 16 bit and 8 bit mode.
User avatar
PhilC
Moderator
Moderator
Posts: 6016
Joined: Fri Mar 23, 2018 8:22 pm

Re: Potential changes on a future board.

Post by PhilC »

PaulJ wrote: Wed May 20, 2020 8:58 pm If you want dip eprom just make an adaptor that plugs into the 68000 socket. Best of both worlds. :)
Its probably what I'll do anyway just because I can I suppose.
If it ain't broke, test it to Destruction.
Post Reply

Return to “MONGREL H4 USER BUILDS”