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The ZX Spectrum SE explained |
aowen
Joined: Oct 31, 2002
Posts: 413
From: Betelgeuse
|  Posted: 2005-07-12 10:51
I've mentioned the machine in a few threads recently so this is intended to answer a few lingering questions. The machine is emulated in FUSE and I understand there is a WIN32 build available.
You can think of the SE as a mix of the Spectrum 128 and the Timex 2068, although it's based on a modified TC2048. The TC2048 and TS2068 share an MMU which in theory offers 256 exclusive banks of 64K to the machine. In the TC2048 only one bank is connected. In the TS2068 the 8K EXROM is connected to one bank and the cartridge port is connected to another. In the SE, 64K RAM is connected to both these banks, giving an extra 128K of memory, and the ability to page out the ROM. The technology to do this is all 1983. On top of this it adds support for ZX128 style memory paging, but owing to hardware issues, in this memory map 144K is available instead of the standard 128K. This gives a 272K machine. The AY chip is available on both the Timex and ZX128 ports. The Timex has two extra video modes - 512x192 in two colours, and 256x192 with 8x1 attribute blocks instead of the normal 8x8 blocks. It also has a shadow of the normal Spectrum display. It uses the RAM area of the normal Spectrum screen at 0x4000 and an area of the same size at 0x6000. The ZX128 also has a shadow of the normal Spectrum screen, stored in one of its pageable 16K banks of RAM. The SE combines both these options, giving four normal screen areas, or two Timex screen areas (hi-res or hi-colour). The default ROM paged as on the ZX128, but in place of the normal 128 editor and 48 Basic ROMs the machine uses the original ROM from the original Spectrum in place of the 48 Basic ROM (this improves compatibility) and a modified version of the editor which works with this ROM. You may have heard of SE Basic - this is a related project and when it is finished it will replace the original Spectrum ROM and Z80 BBC Basic will replace the 128 Editor ROM. It will be possible to emulate the original Basic or 128 Basic if necessary. Owing to the ability to page RAM in place of the ROM it is already possible to emulate the ZX80, ZX81/TS1000, and Timex 2068 (although not the cartridges). It is also possible to use any custom 16K ROM including Interface II ROMs and modified versions of BASIC.
So to summarize, it's a hardware solution to the emulator ideal of being able to use any software for any machine. In theory it is capable of emulating quite a few other Z80 based machines as well, not least the Z88. It's not a bad platform for new or modified Spectrum games. But mostly it's an answer to a large group of people that said "lets make a new Spectrum". Well that's been done. There are a few titles available: http://zxse.raww.net/ and the rest is up to you - the developers.
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Fikee
Joined: Jul 21, 2003
Posts: 216
From: CZ
| Posted: 2005-07-12 20:52
where i can found some ports descriptions ? for example, if i want to switch to 192*256 "multicolor" mode which bit on which port should be changed ?
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Philip Kendall
Joined: Feb 28, 2002
Posts: 1323 | Posted: 2005-07-13 00:47
Exactly the ones you would on the Timex machines.
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aowen
Joined: Oct 31, 2002
Posts: 413
From: Betelgeuse
| Posted: 2005-07-13 10:14
I should have also included this link with the full technical description including ports:
http://www.sinclairfaq.com/cssfaq/reference/sereference.htm
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wilsonsamm
Joined: Aug 15, 2003
Posts: 168 | Posted: 2005-07-13 14:18
I want one!
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Philip Kendall
Joined: Feb 28, 2002
Posts: 1323 | Posted: 2005-07-13 14:33
Source yourself a Timex machine and send it to Yarek who will mod it for you.
I'd put money on you not actually doing this, though.
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wilsonsamm
Joined: Aug 15, 2003
Posts: 168 | Posted: 2005-07-13 23:09
Quote:
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On 2005-07-13 14:33, Philip Kendall wrote:
I'd put money on you not actually doing this, though.
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Now you've said that I'm determined to do it 
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aowen
Joined: Oct 31, 2002
Posts: 413
From: Betelgeuse
| Posted: 2005-07-14 11:38
Quote:
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On 2005-07-13 23:09, wilsonsamm wrote:
Quote:
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On 2005-07-13 14:33, Philip Kendall wrote:
I'd put money on you not actually doing this, though.
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Now you've said that I'm determined to do it
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Well if you do get one then I'll start a ZX Spectrum SE owners club. At this stage I'm looking at adding the divIDE interface to mine since I'm still having no joy with ZXATASP. Hopefully FUSE will add divIDE support at some point (I think there is already one emulator with it so I guess it's documented somewhere). I'm also planning to rehouse it at some point in a black rack-mount case I bought for the purpose although I may up-end it PS2 style.
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Philip Kendall
Joined: Feb 28, 2002
Posts: 1323 | Posted: 2005-07-14 11:51
Quote:
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On 2005-07-14 11:38, aowen wrote:
Hopefully FUSE will add divIDE support at some point
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It's on the vague list of things to do, if nothing else for the vague irony of emulating a device designed for loading emulator files on a real machine.
Don't hold your breath for it to happen, though.
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aowen
Joined: Oct 31, 2002
Posts: 413
From: Betelgeuse
| Posted: 2005-07-14 14:09
Quote:
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On 2005-07-14 11:51, Philip Kendall wrote:
Quote:
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On 2005-07-14 11:38, aowen wrote:
Hopefully FUSE will add divIDE support at some point
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It's on the vague list of things to do, if nothing else for the vague irony of emulating a device designed for loading emulator files on a real machine.
Don't hold your breath for it to happen, though.
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Well, if divIDE works on my actual SE then I'll be quite happy to continue to use ZXCF on my emulated one. Although it would be nice to get the divIDE OS to support patches to the ZX80, ZX81 and TS2068 loading routines which might solve the current problem of loading ZX80 and ZX81 software into their respective emulators on the SE.
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