TS Expansion Interface
4 messages · 2004-11-28 → 2004-11-28 · Yahoo Group era · View archive on archive.org
Participants: Jeff, bryankvines, Jarek Adamski, Jeff Burrell
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.
Messages
1. Re: [ts2068] TS Expansion Interface
Jarek Adamski · Sun, 28 Nov 2004 07:33
Cytowanie Jeff <[email]>:
> I would recommend buffering all of the TS lines to the
> new motherboard. This is easily done using 74HCT245s or
> equivalent.
This is kind of neccessary.
> One problem is that the truly useful cards (clock, IDE,
> 8 bit VGA, etc) are so old they are hard to get - most
> of these functions have been incorporated into the chip
> sets used on PC motherboards.
In Poland such thing are sold sometimes on auctons like
http://www.allegro.pl or http://a24.pl. You could probably
explore the eBay.
For ISA I have several solutions. One is remapping ISA
ports to #40..#7F ports (with some exceptions) with IM2
vectors range #40..$7E. Second is assess as memory in my
4MB RAM memory map. Also nice solution made people from
France for CPC (it is called CPCISA). Also, I have idea
to connect AT286/386SX boards to use their DMA and
interrupts possibilities.
> A 3.5MHz Z80 has an approximate 1MIPS processing rate
> which would be pretty slow for use with ISA cards.
Zilog made Z84020PTV CPUs working at 20MHz. Also, I would
like to consider the eZ80 for my ZX Spectrum clone.
> The 2068 would also need some sort of memory expansion
> for all of the additional software which leads us back
> to where I am now.
The 4MB RAM upgrade, I've designed for ZX Spectrum looks
like is working correctly. However I have problem with
one interface connected to this computer, so I need to
solve it first. Then, 4MB RAM upgrades will be available
also for TS2068 - they will be like my old TC2144 upgrade.
Of course internal one, to reduce costs, but I'm thinking
also of an external interface (equiped with Z80 CPU to
give more possibilities). Still a lot of work to do.
BTW Jeff - do you find possible to make the TS2068 ULA
clone in FPGA? I'm too far from this technology.
Regards,
--
Jarek Adamski
2. TS Expansion Interface
Jeff · Sun, 28 Nov 2004 02:02
It is entirely possible to build an expansion chassis for the
2068. I would recommend buffering all of the TS lines to the new
motherboard. This is easily done using 74HCT245s or equivalent. I
agree with Jarek that building the interface to use 8 and 16 bit ISA
cards would be the way to go. This would give the possibility of
using these cards for video or other functions. One problem is that
the truly useful cards (clock, IDE, 8 bit VGA, etc) are so old they
are hard to get - most of these functions have been incorporated into
the chip sets used on PC motherboards.
Again, the 2068 would be the bottle neck in a system like this. A
3.5MHz Z80 has an approximate 1MIPS processing rate which would be
pretty slow for use with ISA cards. The 2068 would also need some
sort of memory expansion for all of the additional software which
leads us back to where I am now.
3. Re: TS Expansion Interface
bryankvines · Sun, 28 Nov 2004 02:24
Ah well. At least it kept me out of the Christmas lights for a day. :)
--- In [email], "Jeff" <jburrell7@y...> wrote:
>
> It is entirely possible to build an expansion chassis for the
> 2068. I would recommend buffering all of the TS lines to the new
> motherboard. This is easily done using 74HCT245s or equivalent. I
> agree with Jarek that building the interface to use 8 and 16 bit ISA
> cards would be the way to go. This would give the possibility of
> using these cards for video or other functions. One problem is that
> the truly useful cards (clock, IDE, 8 bit VGA, etc) are so old they
> are hard to get - most of these functions have been incorporated into
> the chip sets used on PC motherboards.
>
> Again, the 2068 would be the bottle neck in a system like this. A
> 3.5MHz Z80 has an approximate 1MIPS processing rate which would be
> pretty slow for use with ISA cards. The 2068 would also need some
> sort of memory expansion for all of the additional software which
> leads us back to where I am now.
4. Re: [ts2068] TS Expansion Interface
Jeff Burrell · Sun, 28 Nov 2004 11:54
Jerek
It would certainly be possible to implement most of the 2068 ULA in an FPGA. The only problem is the D/A converter for the video. A 200K gate FPGA could comfortably hold the Z80 processor as well as the ULA.
Jarek Adamski <[email]> wrote:
Cytowanie Jeff :
> I would recommend buffering all of the TS lines to the
> new motherboard. This is easily done using 74HCT245s or
> equivalent.
This is kind of neccessary.
> One problem is that the truly useful cards (clock, IDE,
> 8 bit VGA, etc) are so old they are hard to get - most
> of these functions have been incorporated into the chip
> sets used on PC motherboards.
In Poland such thing are sold sometimes on auctons like
http://www.allegro.pl or http://a24.pl. You could probably
explore the eBay.
For ISA I have several solutions. One is remapping ISA
ports to #40..#7F ports (with some exceptions) with IM2
vectors range #40..$7E. Second is assess as memory in my
4MB RAM memory map. Also nice solution made people from
France for CPC (it is called CPCISA). Also, I have idea
to connect AT286/386SX boards to use their DMA and
interrupts possibilities.
> A 3.5MHz Z80 has an approximate 1MIPS processing rate
> which would be pretty slow for use with ISA cards.
Zilog made Z84020PTV CPUs working at 20MHz. Also, I would
like to consider the eZ80 for my ZX Spectrum clone.
> The 2068 would also need some sort of memory expansion
> for all of the additional software which leads us back
> to where I am now.
The 4MB RAM upgrade, I've designed for ZX Spectrum looks
like is working correctly. However I have problem with
one interface connected to this computer, so I need to
solve it first. Then, 4MB RAM upgrades will be available
also for TS2068 - they will be like my old TC2144 upgrade.
Of course internal one, to reduce costs, but I'm thinking
also of an external interface (equiped with Z80 CPU to
give more possibilities). Still a lot of work to do.
BTW Jeff - do you find possible to make the TS2068 ULA
clone in FPGA? I'm too far from this technology.
Regards,
--
Jarek Adamski
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