[N8VEM: 16863] Next Steps after Zeta Completion

[Andrew Bingham]

So, I am rapidly approaching the completion of my Zeta/ParPortProp build,
which is a "first introduction" to homebrew computer building and CP/M.
I'll spend some time loading different software onto the mahine and
playing around with the OS

I'm trying to figure out what some good next steps might be. I have picked
up some hardware while working on the Zeta which would allow me to go in
either the direction of ECB or S-100:
-One of the Siemens PLC chassis with the 12 slots that were mentioned as a
good candidate for an ECB system
-A Vector Graphics MZ w/ZCB board, Flashwriter II terminal card, 64KB of
SRAM, and Micropolis FDC card & 18 slot S-100 backplane.

It seems like in general the ECB PCBs are more available, but there is a
wider range of CPU card options in the S-100. The availability of RomWBW
seems like a plus for ECB in terms of having working BIOS software while
getting up and running - the S-100 software for each card seems to be out
there but it looks like I'd have to put it together manually.

I've also seen several mentions of a Zeta->ECB "shim board" project that I
might be willing to help finish, rather than building one of the ECB SBCs.

Andrew

[Sergey]

Andrew,

My opinion could be a bit biased, but I'd go with ECB. It is more compact,
no need to mess with power supplies (+5V and maybe +12V is enough), and as
you mentioned RomWBW covers pretty much all ECB/Z80 boards.

Regarding the shim board, I am attaching the latest version of the design.
I haven't tried building it, but it should work... hopefully other people
on this list can review the schematic and provide some feedback.

One useful thing that can be added to the shim board is wait state
generator - basically check if I/O request is going to ECB and insert some
wait states. This will allow running Zeta on 20 MHz, with slower ECB
peripheral boards.

The board dimensions allow installing it on top of Zeta (between Zeta and
floppy drive, if you have one). The ECB connector then sticks out on the
right side.

Thanks,
Sergey

Post by Andrew Bingham
So, I am rapidly approaching the completion of my Zeta/ParPortProp build,
which is a "first introduction" to homebrew computer building and CP/M.
I'll spend some time loading different software onto the mahine and
playing around with the OS
I'm trying to figure out what some good next steps might be. I have
picked up some hardware while working on the Zeta which would allow me to
-One of the Siemens PLC chassis with the 12 slots that were mentioned as a
good candidate for an ECB system
-A Vector Graphics MZ w/ZCB board, Flashwriter II terminal card, 64KB of
SRAM, and Micropolis FDC card & 18 slot S-100 backplane.
It seems like in general the ECB PCBs are more available, but there is a
wider range of CPU card options in the S-100. The availability of RomWBW
seems like a plus for ECB in terms of having working BIOS software while
getting up and running - the S-100 software for each card seems to be out
there but it looks like I'd have to put it together manually.
I've also seen several mentions of a Zeta->ECB "shim board" project that I
might be willing to help finish, rather than building one of the ECB SBCs.
Andrew

[Andrew Lynch]

Hi
 
I agree.  A Zeta to ECB bridge shim would be a very good thing.  It would be purely optional but would provide at least a gateway to the ECB backplane and its peripherals.  The Zeta SBC is great but Zeta + ECB would be even better IMO.
 
I suppose you could use the Z80 socket to ECB shim on the Zeta for a single ECB board but that's kind of missing the point.  Having an option for a bus backplane really opens up the amount and variety of expansion especially to support those unique requirements that home brew hobbyists have interests.  Specialized boards like uPD7220 GDC and Cassette IO fall are examples but there are plenty more.
 
Thanks and have a nice day!
 
Andrew Lynch

From: Sergey <skiselev-***@public.gmane.org>
To: n8vem-/***@public.gmane.org
Sent: Thursday, December 26, 2013 1:37 AM
Subject: [N8VEM: 16866] Re: Next Steps after Zeta Completion



Andrew,

My opinion could be a bit biased, but I'd go with ECB. It is more compact, no need to mess with power supplies (+5V and maybe +12V is enough), and as you mentioned RomWBW covers pretty much all ECB/Z80 boards.

Regarding the shim board, I am attaching the latest version of the design. I haven't tried building it, but it should work... hopefully other people on this list can review the schematic and provide some feedback.

One useful thing that can be added to the shim board is wait state generator - basically check if I/O request is going to ECB and insert some wait states. This will allow running Zeta on 20 MHz, with slower ECB peripheral boards.

The board dimensions allow installing it on top of Zeta (between Zeta and floppy drive, if you have one). The ECB connector then sticks out on the right side.

Thanks,
Sergey

On Wednesday, December 25, 2013 11:29:16 AM UTC-8, Andrew Bingham wrote:
So, I am rapidly approaching the completion of my Zeta/ParPortProp build, which is a "first introduction" to homebrew computer building and CP/M.  I'll spend some time loading different software onto the mahine and playing around with the OS

-One of the Siemens PLC chassis with the 12 slots that were mentioned as a good candidate for an ECB system
-A Vector Graphics MZ w/ZCB board, Flashwriter II terminal card, 64KB of SRAM, and Micropolis FDC card & 18 slot S-100 backplane.
It seems like in general the ECB PCBs are more available, but there is a wider range of CPU card options in the S-100. The availability of RomWBW seems like a plus for ECB in terms of having working BIOS software while getting up and running - the S-100 software for each card seems to be out there but it looks like I'd have to put it together manually.
I've also seen several mentions of a Zeta->ECB "shim board" project that I might be willing to help finish, rather than building one of the ECB SBCs.
Andrew--

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[Andrew Bingham]

So, this board uses a double-sided-pins DIL40 like what is shown on this
website (http://raster.infos.cz/atari/hw/stereo/stereoen.htm) soldered on
the bottom of the board, which plugs into the socket for the Z80 on the
Zeta, and then the Z80 plugs into this board instead? What is the function
of the 2x20 connector that has all the bus signals routed to it, test
points for debugging?

Mostly I was looking for something that I could do to contribute to one of
the board designs, and I saw that Andrew L had mentioned doing a build and
testing of this board several times as a step to allow all the Zeta
builders to grow their systems. I think this is a good goal.

I guess I would need an ECB backplane and at least 1 other ECB card to test
this?

Is there any software reason that the ParPortProp wouldn't be able to be
used with the Zeta + and ECB Backplane?

Andrew

Hi
I agree. A Zeta to ECB bridge shim would be a very good thing. It would
be purely optional but would provide at least a gateway to the ECB
backplane and its peripherals. The Zeta SBC is great but Zeta + ECB would
be even better IMO.
I suppose you could use the Z80 socket to ECB shim on the Zeta for a
single ECB board but that's kind of missing the point. Having an option
for a bus backplane really opens up the amount and variety of expansion
especially to support those unique requirements that home brew hobbyists
have interests. Specialized boards like uPD7220 GDC and Cassette IO fall
are examples but there are plenty more.
Thanks and have a nice day!
Andrew Lynch
*Sent:* Thursday, December 26, 2013 1:37 AM
*Subject:* [N8VEM: 16866] Re: Next Steps after Zeta Completion
Andrew,
My opinion could be a bit biased, but I'd go with ECB. It is more compact,
no need to mess with power supplies (+5V and maybe +12V is enough), and as
you mentioned RomWBW covers pretty much all ECB/Z80 boards.
Regarding the shim board, I am attaching the latest version of the design.
I haven't tried building it, but it should work... hopefully other people
on this list can review the schematic and provide some feedback.
One useful thing that can be added to the shim board is wait state
generator - basically check if I/O request is going to ECB and insert some
wait states. This will allow running Zeta on 20 MHz, with slower ECB
peripheral boards.
The board dimensions allow installing it on top of Zeta (between Zeta and
floppy drive, if you have one). The ECB connector then sticks out on the
right side.
Thanks,
Sergey
So, I am rapidly approaching the completion of my Zeta/ParPortProp build,
which is a "first introduction" to homebrew computer building and CP/M.
I'll spend some time loading different software onto the mahine and
playing around with the OS
I'm trying to figure out what some good next steps might be. I have
picked up some hardware while working on the Zeta which would allow me to
-One of the Siemens PLC chassis with the 12 slots that were mentioned as a
good candidate for an ECB system
-A Vector Graphics MZ w/ZCB board, Flashwriter II terminal card, 64KB of
SRAM, and Micropolis FDC card & 18 slot S-100 backplane.
It seems like in general the ECB PCBs are more available, but there is a
wider range of CPU card options in the S-100. The availability of RomWBW
seems like a plus for ECB in terms of having working BIOS software while
getting up and running - the S-100 software for each card seems to be out
there but it looks like I'd have to put it together manually.
I've also seen several mentions of a Zeta->ECB "shim board" project that I
might be willing to help finish, rather than building one of the ECB SBCs.
Andrew
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[Sergey]

That was the idea - one DIP40 socket is for connecting to the Zeta SBC,
another one for Z80 itself. The 40 pin header is in case somebody wants to
use this board with some other Z80 based SBC (not Zeta). In this case a
ribbon cable can be used to connect the shim board.
Of course you can modify the layout if you want.

If you like to work on this project I can send you the KiCad files.

I don't see any reason (software or hardware) why ParPortProp wouldn't work
with Zeta and ECB shim board. ParPortProp is using 8255 to interface to
Zeta, not the ECB or Z80 bus. Actually ParPortProp will work with N8VEM SBC
V2 as well :-).

Thanks,
Sergey

Post by Andrew Bingham
So, this board uses a double-sided-pins DIL40 like what is shown on this
website (http://raster.infos.cz/atari/hw/stereo/stereoen.htm) soldered on
the bottom of the board, which plugs into the socket for the Z80 on the
Zeta, and then the Z80 plugs into this board instead? What is the function
of the 2x20 connector that has all the bus signals routed to it, test
points for debugging?
Mostly I was looking for something that I could do to contribute to one of
the board designs, and I saw that Andrew L had mentioned doing a build and
testing of this board several times as a step to allow all the Zeta
builders to grow their systems. I think this is a good goal.
I guess I would need an ECB backplane and at least 1 other ECB card to
test this?
Is there any software reason that the ParPortProp wouldn't be able to be
used with the Zeta + and ECB Backplane?
Andrew

Hi
I agree. A Zeta to ECB bridge shim would be a very good thing. It would
be purely optional but would provide at least a gateway to the ECB
backplane and its peripherals. The Zeta SBC is great but Zeta + ECB would
be even better IMO.
I suppose you could use the Z80 socket to ECB shim on the Zeta for a
single ECB board but that's kind of missing the point. Having an option
for a bus backplane really opens up the amount and variety of expansion
especially to support those unique requirements that home brew hobbyists
have interests. Specialized boards like uPD7220 GDC and Cassette IO fall
are examples but there are plenty more.
Thanks and have a nice day!
Andrew Lynch
*Sent:* Thursday, December 26, 2013 1:37 AM
*Subject:* [N8VEM: 16866] Re: Next Steps after Zeta Completion
Andrew,
My opinion could be a bit biased, but I'd go with ECB. It is more
compact, no need to mess with power supplies (+5V and maybe +12V is
enough), and as you mentioned RomWBW covers pretty much all ECB/Z80 boards.
Regarding the shim board, I am attaching the latest version of the
design. I haven't tried building it, but it should work... hopefully other
people on this list can review the schematic and provide some feedback.
One useful thing that can be added to the shim board is wait state
generator - basically check if I/O request is going to ECB and insert some
wait states. This will allow running Zeta on 20 MHz, with slower ECB
peripheral boards.
The board dimensions allow installing it on top of Zeta (between Zeta and
floppy drive, if you have one). The ECB connector then sticks out on the
right side.
Thanks,
Sergey
So, I am rapidly approaching the completion of my Zeta/ParPortProp build,
which is a "first introduction" to homebrew computer building and CP/M.
I'll spend some time loading different software onto the mahine and
playing around with the OS
I'm trying to figure out what some good next steps might be. I have
picked up some hardware while working on the Zeta which would allow me to
-One of the Siemens PLC chassis with the 12 slots that were mentioned as
a good candidate for an ECB system
-A Vector Graphics MZ w/ZCB board, Flashwriter II terminal card, 64KB of
SRAM, and Micropolis FDC card & 18 slot S-100 backplane.
It seems like in general the ECB PCBs are more available, but there is a
wider range of CPU card options in the S-100. The availability of RomWBW
seems like a plus for ECB in terms of having working BIOS software while
getting up and running - the S-100 software for each card seems to be out
there but it looks like I'd have to put it together manually.
I've also seen several mentions of a Zeta->ECB "shim board" project that
I might be willing to help finish, rather than building one of the ECB SBCs.
Andrew
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[Andrew Bingham]

Well, I've never ordered PCBs, so I think I can get an "introductory" deal
from one of the PCB places to get some prototypes made. Enough for me to
test and to have a couple more to send to other folks.

I don't know if there is a lot more work to be done to the KiCad files,
although I'll sit and stare at it and make sure I understand what it all
does.

Andrew

Post by Sergey
That was the idea - one DIP40 socket is for connecting to the Zeta SBC,
another one for Z80 itself. The 40 pin header is in case somebody wants to
use this board with some other Z80 based SBC (not Zeta). In this case a
ribbon cable can be used to connect the shim board.
Of course you can modify the layout if you want.
If you like to work on this project I can send you the KiCad files.
I don't see any reason (software or hardware) why ParPortProp wouldn't
work with Zeta and ECB shim board. ParPortProp is using 8255 to interface
to Zeta, not the ECB or Z80 bus. Actually ParPortProp will work with N8VEM
SBC V2 as well :-).
Thanks,
Sergey

Post by Andrew Bingham
So, this board uses a double-sided-pins DIL40 like what is shown on this
website (http://raster.infos.cz/atari/hw/stereo/stereoen.htm) soldered
on the bottom of the board, which plugs into the socket for the Z80 on the
Zeta, and then the Z80 plugs into this board instead? What is the function
of the 2x20 connector that has all the bus signals routed to it, test
points for debugging?
Mostly I was looking for something that I could do to contribute to one
of the board designs, and I saw that Andrew L had mentioned doing a build
and testing of this board several times as a step to allow all the Zeta
builders to grow their systems. I think this is a good goal.
I guess I would need an ECB backplane and at least 1 other ECB card to
test this?
Is there any software reason that the ParPortProp wouldn't be able to be
used with the Zeta + and ECB Backplane?
Andrew

Hi
I agree. A Zeta to ECB bridge shim would be a very good thing. It
would be purely optional but would provide at least a gateway to the ECB
backplane and its peripherals. The Zeta SBC is great but Zeta + ECB would
be even better IMO.
I suppose you could use the Z80 socket to ECB shim on the Zeta for a
single ECB board but that's kind of missing the point. Having an option
for a bus backplane really opens up the amount and variety of expansion
especially to support those unique requirements that home brew hobbyists
have interests. Specialized boards like uPD7220 GDC and Cassette IO fall
are examples but there are plenty more.
Thanks and have a nice day!
Andrew Lynch
*Sent:* Thursday, December 26, 2013 1:37 AM
*Subject:* [N8VEM: 16866] Re: Next Steps after Zeta Completion
Andrew,
My opinion could be a bit biased, but I'd go with ECB. It is more
compact, no need to mess with power supplies (+5V and maybe +12V is
enough), and as you mentioned RomWBW covers pretty much all ECB/Z80 boards.
Regarding the shim board, I am attaching the latest version of the
design. I haven't tried building it, but it should work... hopefully other
people on this list can review the schematic and provide some feedback.
One useful thing that can be added to the shim board is wait state
generator - basically check if I/O request is going to ECB and insert some
wait states. This will allow running Zeta on 20 MHz, with slower ECB
peripheral boards.
The board dimensions allow installing it on top of Zeta (between Zeta
and floppy drive, if you have one). The ECB connector then sticks out on
the right side.
Thanks,
Sergey
So, I am rapidly approaching the completion of my Zeta/ParPortProp
build, which is a "first introduction" to homebrew computer building and
CP/M. I'll spend some time loading different software onto the mahine and
playing around with the OS
I'm trying to figure out what some good next steps might be. I have
picked up some hardware while working on the Zeta which would allow me to
-One of the Siemens PLC chassis with the 12 slots that were mentioned as
a good candidate for an ECB system
-A Vector Graphics MZ w/ZCB board, Flashwriter II terminal card, 64KB of
SRAM, and Micropolis FDC card & 18 slot S-100 backplane.
It seems like in general the ECB PCBs are more available, but there is a
wider range of CPU card options in the S-100. The availability of RomWBW
seems like a plus for ECB in terms of having working BIOS software while
getting up and running - the S-100 software for each card seems to be out
there but it looks like I'd have to put it together manually.
I've also seen several mentions of a Zeta->ECB "shim board" project that
I might be willing to help finish, rather than building one of the ECB SBCs.
Andrew
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[roman fulek]

Sergey, I see U4 has pin 1 connected to GND. Will it not talk to Zeta's
data bus anytime when DATA_DIR signal is active ? I do know what BUSAK is
what for. Sorry if I am asking something obvious.

Post by Sergey
That was the idea - one DIP40 socket is for connecting to the Zeta SBC,
another one for Z80 itself. The 40 pin header is in case somebody wants to
use this board with some other Z80 based SBC (not Zeta). In this case a
ribbon cable can be used to connect the shim board.
Of course you can modify the layout if you want.
If you like to work on this project I can send you the KiCad files.
I don't see any reason (software or hardware) why ParPortProp wouldn't
work with Zeta and ECB shim board. ParPortProp is using 8255 to interface
to Zeta, not the ECB or Z80 bus. Actually ParPortProp will work with N8VEM
SBC V2 as well :-).

[Sergey]

Hi Roman,

Sorry I don't see that it is connected to GND (but maybe I am missing
something). The pin 1 of U4 is connected to DATA_DIR, that signal is
generated by the "ECB data bus direction" circuit, just on the right from
U4.
Pins 19 (/G) of all 74*245 are connected to the GND. The idea is that
always one of the sides is driving address / data bus, so outputs are never
in high-Z state.
/BUSAK signal is generated by Z80 to indicate that it released buses to DMA
controller. If that signal is active (LOW), address and control signals are
expected to come from ECB bus to the SBC, and so transceivers direction
switched accordingly.

Thanks,
Sergey

Post by roman fulek
Sergey, I see U4 has pin 1 connected to GND. Will it not talk to Zeta's
data bus anytime when DATA_DIR signal is active ? I do know what BUSAK is
what for. Sorry if I am asking something obvious.

Post by Sergey
That was the idea - one DIP40 socket is for connecting to the Zeta SBC,
another one for Z80 itself. The 40 pin header is in case somebody wants to
use this board with some other Z80 based SBC (not Zeta). In this case a
ribbon cable can be used to connect the shim board.
Of course you can modify the layout if you want.
If you like to work on this project I can send you the KiCad files.
I don't see any reason (software or hardware) why ParPortProp wouldn't
work with Zeta and ECB shim board. ParPortProp is using 8255 to interface
to Zeta, not the ECB or Z80 bus. Actually ParPortProp will work with N8VEM
SBC V2 as well :-).

[roman fulek]

Sorry I meant pin 19 of U4. I see, so it is not like the Zeta is always
master. "ECB data bus direction" circuit is more or less clear to me. Only
point that made me wonder, is for example, when SRAM on Zeta's board is
beiing accessed by the CPU and at the same time DATA_DIR makes left side of
U4 active. That would be conflict.

Post by Sergey
Hi Roman,
Sorry I don't see that it is connected to GND (but maybe I am missing
something). The pin 1 of U4 is connected to DATA_DIR, that signal is
generated by the "ECB data bus direction" circuit, just on the right from
U4.
Pins 19 (/G) of all 74*245 are connected to the GND. The idea is that
always one of the sides is driving address / data bus, so outputs are never
in high-Z state.
/BUSAK signal is generated by Z80 to indicate that it released buses to
DMA controller. If that signal is active (LOW), address and control signals
are expected to come from ECB bus to the SBC, and so transceivers direction
switched accordingly.
Thanks,
Sergey

Post by roman fulek
Sergey, I see U4 has pin 1 connected to GND. Will it not talk to Zeta's
data bus anytime when DATA_DIR signal is active ? I do know what BUSAK is
what for. Sorry if I am asking something obvious.

Post by Sergey
That was the idea - one DIP40 socket is for connecting to the Zeta SBC,
another one for Z80 itself. The 40 pin header is in case somebody wants to
use this board with some other Z80 based SBC (not Zeta). In this case a
ribbon cable can be used to connect the shim board.
Of course you can modify the layout if you want.
If you like to work on this project I can send you the KiCad files.
I don't see any reason (software or hardware) why ParPortProp wouldn't
work with Zeta and ECB shim board. ParPortProp is using 8255 to interface
to Zeta, not the ECB or Z80 bus. Actually ParPortProp will work with N8VEM
SBC V2 as well :-).