But maybe we can already discuss about an Enterprise port. I would like to know some data about the EP:
- what are the bankswitching possibilities? In which ways can the Z80 access more than 64K?
Yes, the total addressable space is 4096K. The memory is segmented. Each segment is 16K, the total 4096K=256*16K segments. Numbered from 00H to FFH
The Z80 memory space is divided to 4 pages
0000H-3FFFH: page 0
4000H-7FFFH: page 1
8000H-BFFFH: page 2
C000H-FFFFH: page 3
You can switch any segment to any Z80 page. The page select ports are the B0H-B3H (in the DAVE chip), this select segments to page0-page3.
Any segments can be a ROM or RAM.
The default memory configuration:
00H-03H internal ROM
04H-07H external ROM cartridge socket (for Basic interpreter or other programs)
F8H-FBH second 64K RAM of EP128
FCH-FFH first 64K RAM (The EP64 only have this)
The top of FFH segment used by the EXOS (operating system) for system areas.
Many hungarian machines have 521K memory extensions. (And new memory extension cards will coming
![Smiley :)](/Smileys/phpbb/smiley.gif)
)
- what are the screen modes/resolutions? How is the video ram organized and where in memory is it placed?
The NICK chip (video chip) have great feauters. You can define the screen memory everywhere in the video RAM, you can define differentc screen modes to every pixel line!
Easy work to bulid CPC type screens.
The NICK can access 64K video RAM, from the Z80 this is the FCH-FFH segments.
- are there standard floppy drives and file systems existing?
EXDOS the disk controller card, using standard floppy disk drives (40 or 80 tracks, 1 or 2 side: from 180K up to 720K), can use up to 4 drives.
The disk format is standard MS-DOS compatible, FAT-12 filesystem. The disk format is officialy 9 (or
![Cool 8)](/Smileys/phpbb/ds_icon_cool.gif)
sectors/track. Unofficially up to 11 sectors/track, and tracks up to 90 (this is depend of the current floppy drive, but up 84 tracks is "standard")
The disk controller use WD 1770/1772 controller chips.
With some hw modiffications (developed by me
![Smiley :)](/Smileys/phpbb/smiley.gif)
)the EXDOS can use HD floppy drives (1.2/1.44Mb), using the standard PC compatible HD disks, or unnofficialy format up to 22 sectors/track on 1.44Mb disks.
The EXDOS have built in RAMDISK support, the RAMDISK is use standard FAT12 filesystem.
On Enterprise you have many points where can handle the disks.
With EXOS calls, this is file level access, and with the EXDOS command calls, can use any EXDOS commands (this is standard DOS commands, CD, COPY, MOVE, REN, FORMAT, etc).
With EXDOS calls can use DOS, CP/M like calls (File controll blocks and etc).
With other EXDOS calls can read/write any sectors of any EXDOS logical drives.
And the floppy handler part of the EXDOS have direct entry point, this is the DISKIO calls, with this the low level handler for floppy drives.
And now I developed IDE disk controller card
![Smiley :)](/Smileys/phpbb/smiley.gif)
some words about this will coming...
- are there emulators for the Enterprise available? Do they contain a monitor/debugger?
The EP32 is have, but not too perfect
![Sad :(](/Smileys/phpbb/ds_icon_sad.gif)
but I hope will coming new better version
![Smiley :)](/Smileys/phpbb/smiley.gif)