great idea! I make this on each of the PCB-design of me. Of course,
fixed address need not so much hardware. But: You are not flexible and
if You wnat to use more then one PCB of one type, You have an problem.
Please be carefull with 74HC688. ECB is normally specified for LS-TTL.
This depends on Fan-In and Fan-Out. For an decoder it works, but not for
drivers etc. You may also use 74LS682, but i like the 74LS688 more
because he has the "Enable" - Input. Ok, You need an resistor-network
left over on my designs....
Post by James MoxhamMany thanks Wolfgang,
Ah yes, the clones would not have these 'undocumented operations'.
Ok, maybe I see another solution. I can add a 74HC688 chip, and then a
row of jumpers and the user can select this themselves. That might be
better, and it is more flexible that way.
Cheers, James
On Sun, 05 Jan 2014 20:18:14 +1030, Wolfgang Kabatzke
Hi James,
free or not free, this depends on Your configuration.
Full free must be 00-0FH amd F0-FFH.
If You have no uPD7220 are also free 80-8FH. And if You have no
EF9366 (is not finished yet) and no ECB-RAMF and no ECB-ModPrn You
may use the full area from 90H-DFH. 48H-4FH must be also free. I
built up my own PropIO with only one Propeller. So I have learned
that 4hH-43H is for Prop Nr. 1 and 44H-47H is for Prop. Nr. 2. If
You have nor PropIO is also free 40-4FH.
But please be careful. Normally the Z80 can use for standard
IO-Operations only A0-A7. If You will use A0-A15 You must use
memory mapped IO. But then is an IO-Port = memory address.... And
our memory is "full in use".
4.4 16 Bit I/O ports
OÄ
cially the Z80 has an 8 bit I/O port address space. When using
the I/O ports, the 16 address
lines are used. And in fact, the high 8 bit do actually have some
value, so you can use 65536
ports after all. IN r,(C), OUT (C),r, and the Block I/O
instructions actually place the entire BC
register on the address bus. Similarly IN A,(n) and OUT (n),A put
A Å 256 + n on the address
bus.
The INI/INIR/IND/INDR instructions use BC after decrementing B,
and the OUTI/OTIR/OUTD/OTDR
instructions before
Please be careful with this content. I know that this
"undocumented operations" are not running on each Z80-CPU I know
(because I developed computers in the former GDR) that the
"undocumented options" on GDR-CPU are not usable. The GDR built
not simple clons, they developed an CPU "conform to documentation"
:-P .
Best regards and have a nice day
Wolfgang
Post by James MoxhamHi Wolfgang,
Thanks for the fast reply!
But it looks like only 00H-10H and F0H to FFH are free?
Or could I use 48H to 4FH as these look to be free. Maybe I will use those?
Of course, if we added an 8 input OR gate to A8-A15 on all the
boards we could have had 65536 port addresses, as documented on
page 17 of this pdf http://www.z80.info/zip/z80-documented.pdf
But that would mean changing all the boards out there!
Thankyou very much for this table - it is most helpful
Cheers, James
On Sun, 05 Jan 2014 19:44:12 +1030, Wolfgang Kabatzke
Post by James Moxham (Dr_Acula)I'm building a board for the ECB bus and I need to choose a
port address to talk to the board (or 4 consecutive
addresses to be precise).
Is there a repository of port addresses listed somewhere?
The closest I could find was a list of addresses on the zeta
page. If we don't have such a list, would it be useful to
create a list to avoid potential conflicts in the future? I
could just pick some random number above 200 as I don't they
are being used, but it would be better to be sure it doesn't
clash with anyone else's board :)
Cheers and many thanks in advance.
James Moxham
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Hi James,
I wrote for my ECB-RAMF-Floppy this table
Base-address table
AD7 AD6 AD5 AD4 AD3 AD2
0 0 0 0
00H free
0 0 0 1
10H preferred for ECB Zilog Peripherals
0 0 1 0
20H reserved for ECB Disk IO
0 0 1 1
30H reserved for ECB Disk IO
0 1 0 0
40H 40H - 47H preferred for PropIO
0 1 0 1
50H 50H - 58H preferred for ECB SCG board
0 1 1 0
60H reserved for N8VEM SBC V2
0 1 1 1
70H reserved for N8VEM SBC V2
1 0 0 0
80H preferred for uPD7220 board
1 0 0 1
90H** preferred for EF9366 board VDU****
*1 0 1 0 0 0 A0H
****preferred****for ECB-RAMF R1.1 #1*
*1 0 1 1 0 1 A4H
****preferred****for ECB-RAMF R1.1 #2*
1 1 0 0 C0H prefered for ECB-ModPrn R0.2
#1 and
#2 (if used in system)
1 1 0 1 D0H
prefered for ECB-4PIO (if used in
system) or preferred for EF9366 board Hardware scroll**
1 1 1 0 E0H
preferred for ECB ColorVDU board
1 1 1 1
F0H free
http://n8vem-sbc.pbworks.com/w/page/62304153/N8VEM%20SBC%20V2%20Input%20Output%20Addresses
Best regards
Wolfgang
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Dr.-Ing. Wolfgang Kabatzke
Hansastrasse 9
DE - 21 502 Geesthacht
Deutschland / Germany
Phone: +49 4152 93 18 130 NEW!!!
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Hansastrasse 9
DE - 21 502 Geesthacht
Deutschland / Germany
Phone: +49 4152 93 18 130 NEW!!!
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Dr.-Ing. Wolfgang Kabatzke