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TS1500 and ZXPand
Posted: Tue Nov 21, 2017 3:00 pm
by Lardo Boffin
I have just received an edge expander from pokemon via Sell My Retro and look at this!
A nice hires game loaded from my ‘spand:-
A marvelous edge connector:-
The only issue i have found using my spand with the TS1500 is that if I reset it I have to cycle the power - it always comes up with an error. It doesn’t do this on my other zeddies. A small price to pay.
Thanks to Bean for suggesting the printer connection idea.
Bean wrote: ↑Thu Nov 02, 2017 2:30 pm
I use a ZXpand on my TS1500 by plugging the TS2040 printer in first. Works fine.
Re: TS1500 and ZXPand
Posted: Tue Nov 21, 2017 3:26 pm
by sirmorris
Nice job!
However I feel I should warn about the fact that both the ZXpand and the TS1500 can simultaneously try to drive the bus when accessing RAM above 32k.
When the '1500 has external memory pulling on its RAMCS line on the edge connector it remaps the internal 16k to sit at 32k. If you start POKEing around nothing bad should come of it because both memory will be reading the bus, but PEEKing will have both ram chips outputting at the same time. If RAM has previously been initialised to some value in that range then both chips will be driving the same value which may be OK. If the RAM is uninitialised then they may drive different values - I don't know what would happen in this case.
Re: TS1500 and ZXPand
Posted: Tue Nov 21, 2017 3:30 pm
by Lardo Boffin
sirmorris wrote: ↑Tue Nov 21, 2017 3:26 pm
Nice job!
However I feel I should warn about the fact that both the ZXpand and the TS1500 can simultaneously try to drive the bus when accessing RAM above 32k.
When the '1500 has external memory pulling on its RAMCS line on the edge connector it remaps the internal 16k to sit at 32k. If you start POKEing around nothing bad should come of it because both memory will be reading the bus, but PEEKing will have both ram chips outputting at the same time. If RAM has previously been initialised to some value in that range then both chips will be driving the same value which may be OK. If the RAM is uninitialised then they may drive different values - I don't know what would happen in this case.
Heard loud and clear! At my risk in case it blows up.
To be honest I will only be using it to play the games I find too irritating on the normal zeddy keyboard.
Re: TS1500 and ZXPand
Posted: Tue Nov 21, 2017 6:01 pm
by gammaray
The 1500 has a routine to switch to channel 2 or 3 by pressing that number in the first few seconds after power on. That may have something to do with reset problems.
Now you HAVE to add a KDLX48 by Pokemon for the Spectrum it fits the 1500.
Charles
Re: TS1500 and ZXPand
Posted: Tue Nov 21, 2017 11:11 pm
by Lardo Boffin
gammaray wrote: ↑Tue Nov 21, 2017 6:01 pm
The 1500 has a routine to switch to channel 2 or 3 by pressing that number in the first few seconds after power on. That may have something to do with reset problems.
Now you HAVE to add a KDLX48 by Pokemon for the Spectrum it fits the 1500.
Charles
Funnily enough i was looking at those and wondering....
Re: TS1500 and ZXPand
Posted: Tue Nov 21, 2017 11:22 pm
by gammaray
I have converted two with the KDLX. Cuz the Chiclet keyboard is better but not as good as the KDLX!
Re: TS1500 and ZXPand
Posted: Tue Nov 21, 2017 11:23 pm
by sirmorris
They are a very worthwhile upgrade. It has to be said.
Re: TS1500 and ZXPand
Posted: Thu Nov 30, 2017 10:18 am
by Paul
I seem to remember that there was a TS1500 GAL for the old ZXPand.
Is that correct?
Re: TS1500 and ZXPand
Posted: Thu Nov 30, 2017 11:01 am
by sirmorris
Correct.
It is possible to re-program the CPLD on ZXpand+ in-system, in a similar way to the device firmware. So having a 1500 configuration is just a matter of testing. It can give RAM from 16-64k where the 1500's internal memory sits at 32-48k. If I understand It Correctly that is.
Re: TS1500 and ZXPand
Posted: Thu Nov 30, 2017 11:44 am
by Paul
For TS1500 config "m=l" should apply RAM in 8-32K area. And RAMCS always high.
config "m=h" should apply RAM in 16-32 Area. And RAMCS always high.
This way you can switch RAM at 8k on and off (ROM there) and have RAM IN 16-32K area.
The TS1500 then always adds RAM at 32-48k.
This should give maximum compatibility.
Any better ideas?
What did the TS1500 GAL? Anything different?
One should be aware that this ZXPand is TS1500 mode running.
Or can you even add a config command to swap between both modes for ZXPand +?
Auto detection won't be easy...