UDG 4 ZXpand / ZXblast

[PokeMon]

Mine arrived, too. Maybe already yesterday, didn't open my post box yesterday.
Nice looking gadget.

[nollkolltroll]

Andy: a standard Memotech 16k expander should work, right? The address of the UDG char set will have to be different of course.

[Andy Rea]

I don't know, i think the.memotecs used dynamic memory which means their will be sone sort of refresh mechanism, so it very likely that it won't work with such memory...

What I can say is that is if a memory expansion can be used for hi-res graphics then it is likely to work with the UDG board.

Regards Andy

[1024MAK]

The 16k byte Memotech RAM packs use both the Z80 refresh cycle and the normal memory cycles for DRAM refresh.
See this thread

Mark

[Andy Rea]

Bump - listed 10 more boards for sale.

https://www.sellmyretro.com/offer/detai ... pand-28480

regards Andy

[siggi]

A new plug in board that allows the use of external WRX enabled memory

Hi Andy.
I have got a new (old ) Zeddy, having an external 64KByte-Ram of unknown type (probably no WRX). Do you think that it is possible to use your interface (maybe after an update to make also WRX in a "standard" external ram) for that Zeddy?

http://forum.tlienhard.com/phpBB3/viewt ... 907#p32866

Regards
Siggi

[Andy Rea]

Hi Siggi,

As i sure your aware for video patterns to be successfully retrieved from ram ( internal or external ) that ram has to be active during refresh, if that ram is static ram then usually it can be altered ( sometimes extra logic is required ) to be active during the refresh, with dynamic rams it can be much harder to achieve.

The UDG board intercepts the zeddies external address lines ( A0 thru A10) and only during refresh the alternate address is placed on the thru address bus, at all other times the original signal is a pass thru as are all the other signals on the edge connector.

Regards Andy