Memory paging can be in 16kB and 8kB blocks. Now I place bigger CPLD chip on
same PCB and some free pins are reserved for add next components/led
diodes,etc...
Standard SD card slot may be if will free space on PCB. As first I must measure
maximal size inside plastic cartridge case. D/A soundchips (small SMD with SPI
protocol) are very very small and I can place more D/A chips. Each D/A chip
contain two 8bit channels and can be connect as stereo chip or mono 16 bit. With
two D/A chips we can use four 8bit channels, or two 16bit channels. With three
D/A chips we have six 8bit channels or three 16bit channels or combinations.
Each D/A channel can parallel use more ports for compatibility with
soundrive/covox/samdac/eddac without switching of D/A modes and for possibility
run sample trackers from ZX mode without modification. Yes, theoretically is can
add possibility configure manually ports addresses of all D/A channels.
----- Original Message -----
From: "SCjoe" <sam.co...@centrum.cz>
To: "sam-users" <sam-users@nvg.ntnu.no>
Sent: Saturday, February 15, 2014 4:07 PM
Subject: Re: New project - 2MB ram + 512kB flash rom
After many years, experiments, variants and proposals,
it seems that this cheap interface with only two chips (memory and CPLD)
will be put into the production. :-)
With a little bit of imagination, we would think of this board:
- 2 MB external RAM, one-meg compatible, with readable ports
- or 1 MB RAM and 512 KB KB external ROM
- plus 512 KB of the divIDE memory model
- DivIDE memory paging model by 8 KB (also for ext. ROM, please)
- ram pages backups (256 KB or 512 KB standard memory snapshots)
- memory setup through a NMI menu (similar to the "speccyal" PROFI interface)
- Speccy 128K RAM paging (a small modification on the Coupe´s motherboard is
needed)
- NMI button (jump to the menu)
- external ROM ON/OFF button (system start with a modified ROM, ZX ROM or a
special program/menu)
- SD card slot (standard size, please)
- size of the smallest old FAMICOM cartridges (hence a case is available)
Some space still left on the board?
What about to add 3 D/A converters (8bit stereo - 16 bit mono, or any other 6
channels equivalent)
and to set (change) output ports through a NMI menu,
in order to achieve both EDDAC and (partial) Surround compatibility?
Regards
Josef
______________________________________________________________
VELESOFT <veles...@seznam.cz>
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