Another option of Timex cartridge
1 message · 2006-04-25 → 2006-04-25 · Yahoo Group era · View archive on archive.org
Participants: Jarek Adamski
Preserved from the Timex/Sinclair 2068 Yahoo Group (2001–2019), which is no longer online. Text reproduced from the archive.org archive; email addresses masked.
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1. Another option of Timex cartridge
Jarek Adamski · Tue, 25 Apr 2006 09:27
Hello again!
Beside the idea for cardride with 512kB PEROM and 32kB SRAM,
that could work with ZXVSG UPB, I have idea for other cartridge,
of the following functionality:
- 512kB or 1MB PEROM seen in DOCK as 32 banks of 16kB/32kB each.
First 512kB chip seen in area 0..16383 (#0000..#3FFF), second
in 16384..32767 (#4000..#7FFF).
- 128kB or 512kB SRAM seen in DOCK as 8/32 banks of 16kB each,
in area 49152..65535.
- Port 32765 (#7FFD) for partial ZX Spectrum 128K compatibility.
It does not include port lock (useless) and two screens, as this
cannot be made from cartridge. Supported are: two ROM banks as
in ZX Spectrum 128K, 8 extra memory banks (however, banks 5 and
2 are not duplicated in 16384..49151 area - this is useless).
In case of 512kB SRAM chip the memory switching is compatibile
to Pentagon 512kB.
- Extra port for PEROM switching. Similar, but not exactly like
FlashD0 upgrade. http://8bit.yarek.pl/upgrade/zx.flashd0/
- 64kB of PEROM is used for ZXVGS FD0 needs. Another 32kB can
be reserved for better ZX Spectrum 128K emulation (will this
have any use?).
- Rest of PEROM (416kB or 448kB or 928kB or 960kB) is seen as
CP/M disk and can be written from ZXVGS level. Allocation unit
is 2kB and up to 127 files can be written.
- ZXVGS can use many other disk interfaces, both floppy and
IDE. For example can use FDC from ISA I/O card, reading 1640kB
disks (in CP/M format).
- External AY-3-891X can be connected for better compatibility.
--
Jarek Adamski