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Sorry for the silly joke above. Yea hello guys!

Yup.. a new Z80 freak here, lol. Not really a user of the zed 80 other than having a Microsoft Z80 card (that I still have) in my Apple IIe. (apparently Bill wanted 350 bucks for this card!) I am an old developer (turned to sw as of the last few dozen years or so) and one that loved electronics from the 70's and now retired. Also enjoying retro computers of all kind. I have been on the 1802 side for a while here but found out about Lee and his awesome designs for every micro we had .. from back in the day. (Hi Lee) and just bought the Z80MC and in the process of building it. Man I love the LEDs here as well as the IO card. Very cool stuff.

So yea I got the SIO card too. Looking to build it soon and having fun with this retro "uC" from the past (cant beat the cool Docs too Lee) and hope I may be able to contribute to this group as well. Please excuse my typing here and there, I have some cognitive issues and hope you wont mind. Thanks for reading and accepting me into the power of what those old ex-motorola guys saw back in those days that we loved so much.?

(Note: I am not biased by any micro, I do have a life time appreciation for them all!)

Well maybe I am a bit biased on this paper microcomputer....

? hehe, no not really jk! Back in the 70's I was going to get this.

But I was building an 8008 micro at the time, making some texas towers and thought, hmmm maybe I'll leave it to those that want to learn about them. Did I know about them... NO, could I build one.. yes.
LOL, yea Hackaday has a great article about it too. Go Cardiac!

So thats my silly bio for the moment, hope to meet you all and lets push some more 1's and 0's around! See ya!

Tony

On Sun, May 9, 2021 at 08:26 AM, joshbensadon wrote:

Good luck on your Z80MC build.? The "zed 80" was quite a successful processor.?

Hi Josh,
Thank you so much for approving me. Yea, I did not really do enough with that processor years ago (so much changed afterwards as I am sure you all know) but I did see how many systems were created by it and did read a small bit about its architecture. A truly awesome micro. It will be so much fun to now get back into it. See you online!

-Tony

On Sun, May 9, 2021 at 10:28 PM, joshbensadon wrote:

You can only truly appreciate the Z80 when you start using the Repetitive Copy and Compare instructions.?

?

Are you reading any books on the Zed-80?

?

Hi Josh,
I dont remember that instruction, but I know it had quite a few more that were better than the old 8080 as well as an improved register set. I know that the HW took the 3 power supplies from 3 down to 5V only. Really great for that time. IIRC I think that is why Intel came out with the 8085? Wow so many years ago, I am mixing up what they did back then. As I read frm down below, I also mixed up the company names as well. LOL!! I think I was on the 6800 - 6502 path in my mind, not on the 8080 - Z80 path. So many things happened back then. Now so little memory left of what happened as well I believe. HEHE--thank God I am not a writer of computer history and such! lol

As far as books, all I have left relating to the Z80 was the one I got back in the early 80's called "the Z80 microcomputer handbook" by Wlliam Barden jr. I read a bit of it back then when were designing a computer system for a new product that were making but went to the 8048, 8031 and other MCS51 stuff for our final design. I was not into home pc's back then so much for my career but into more controller applications that we were doing. MCS51 rocked the world for us. Home use I went from 1802 and 6502 stuff. Why, I really have no idea. I guess I just liked them all.

On Mon, May 10, 2021 at 12:29 PM, joshbensadon wrote:

I would hang out with my friend Walter, and we would bring out some BYTE or old Popular Electronics magazines and just read through articles, pointing out some interesting hind sight observations.? I'm looking forward to my retirement years!

Hi Josh (and Bill)
Oh so true about looking at old Bytes and PE. I have been reading them every day for quite a few years now, as well as RE. Its fun to see where we are now compared to the late 70's, 80's. I find myself seeing what really happened within a different view now. You would think you new everything at 20 but when you look back, I missed so much fun for the sake of taking on any job to pay the bills.?

I think I live on this site now,...?? with the others favs in there too.

So true about?archive.org Bill. The net is full of great resources now than we have ever imagined.
-Tony

joshbensadon via groups.io wrote:

The "zed 80" was quite a successful processor. It's line up of
peripheral chips made it very much a dream machine. The fact that it
had all these great registers and was backward compatible with the
8080 (mostly) made it a very interesting solution for new and old
systems.

The Z80 was amazing in part because it was such an early microprocessor. It was a huge step ahead of its contemporaries (like the 8080, 6502, 6800, etc.) The others rushed their micros to market; Zilog took more time to get it "right". It's an excellent example of "if you spend just a little more time, you can make it a lot better." That's one reason the Z80 is still produced today; 45 years later!

The features of the Z80 that I really like are:

- simple hardware interface: single 5v supply, simple clock, logical easy-to-use address, data, and control signals.
- included dynamic RAM refresh (important then, less so today).
- rich instruction set: not just the basics, but also relative jumps, 16-bit operations, block moves, indexed addressing, etc.
- plenty of registers, including a duplicate set that can be swapped with a single fast instruction.
- an excellent fast, vectored interrupt structure.

Lee Hart

--
A designer knows he has achieved perfection not when there is
nothing left to add, but when there is nothing left to take away.
-- Antoine de Saint Exupery
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

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On Mon, May 10, 2021 at 01:18 PM, Lee Hart wrote:

The features of the Z80 that I really like are:

- simple hardware interface: single 5v supply, simple clock, logical easy-to-use address, data, and control signals.
- included dynamic RAM refresh (important then, less so today).
- rich instruction set: not just the basics, but also relative jumps, 16-bit operations, block moves, indexed addressing, etc.
- plenty of registers, including a duplicate set that can be swapped with a single fast instruction.
- an excellent fast, vectored interrupt structure.

Hi Lee,
Wow cool list of things to keep in mind. I did not know about dyno-ram refresh ability. I am still going threw the docs and filling up my parts list for the Z80MC. Wow a really awesome design here. I love this board as well as the SIO too. I have been updating some of my old (and new) info with some guys on youtube as well. I found one bright fellow that talks about the z80 called "Advent Of Computing". Fun guy to listen to, but I disagree with him about the words "micro computer" that we talk about. I call them all micros and I always will, lol

Z80,

Been developing and using the Z80 since I got my Northstar Z80 cpu
for Altair in early 1977 at that time a 4mhz part or easily twice the
8080 speed.

I have not less than...
5 Z80 s100 systems??
3 Z80 SBCs? (amproLB+ is still in regular use).
12 VT180 (two complete and 10 Z80 boards which
? ? ?are complete systems sans terminal).? The VT180
? ? ?was a VT100 terminal with a serial connection to a
? ? ?Z80 system floppy and IO complete and 64K of ram.
? ? ?The only shared thing was power supply, case and
? ? ?used the VT100 power on reset signal.
2 TRS80 (early)
And many SBCs of my design using Z80.

I also have a later set of systems based on Z180 (z80 with
integrated peripherals) and Z280 a really extended Z80
with 16 bit bus.

Its a versatile CPU that had dominated the 8bit world?
and the only other that had a significant presence was
the 6502 (AppleII and friends).? ?Both have demonstrated
extended life compared to many.? ?They are the two that
still appear the most besides 8085 and 1802.? Other well
knowns that seem to have disappeared are?6800, TI9900
(not the console but the CPU), Signetics 2650.? What
helped the Z80 stay alive was speed by '81 6mhz was
delivered and a year or two later 8mhz parts.? Now its
possible to find 10 and even 20mhz parts.

It had staying power because of speed,? instruction set and?
peripherals (and could use 8080/8085 supporting parts as well).
Its instruction set including all the 8080 have a large selection
of 16 bit and extended instructions with options for increment
or decrement and repeat.? My favorite is JP NZ,target (also
seen as DJNZ target).? There are three instruction mnemonic
sets in use, official Zilog, one I call Alternate-80 extended,
and TDL.? The latter two use the format most common to
8080/8085.

As to compatibility with 8080, there were a few programs that
behaved wrong on Z80 and that was early.? Later compatible
8080 code noted the small differences in flag use and avoided
those traps.? Smaller systems suffered that but it was both flag
and IO devices used that caused code uniqueness that made
code incompatible.? ?Most of the CP/M 80 applications was
compatible 8080 unless marked as Z80 required [used
extended instructions].? Generally 8080 was binary compatible
with Z80 but and only in carefully crafted cases the reverse
by avoiding the z80 unique instructions.

Comment to date I've not found any z80 that didn't have the
"unsupported instructions".? Same for the 8085 "hidden instructions".
By that point in time semiconductor makers understood the need
to be completely compatible as in identical.

Generally a CP/M user, either CP/M2.2 flavor or Zrdos.?
I have on S100? NorthStar? Horizons that run
NSdos a primitive tag and bag disk monitor but one
of the early mini-floppy (5.25") disk systems as part
of the main box.? There is also Uzi-Z80 a unix look alike.
Most of the other OSs are in the rare or platform unique l
ike TRSdos/Ldos and MSX.? There are a large set of real
time OSs for Z80 as well.

For me its 44 years of z80 and still running.

Allison

saturn5tony via groups.io wrote:

Oh so true about looking at old Bytes and PE. I have been reading them every day for quite a few years now, as well as RE.

I too still have all my old Byte, Dr.Dobbs, REMark, Sextant, QST, etc. magazines, and often go on "archeological digs" for information and entertainment.

I recently got interested in VTL (Very Tiny Language), which was a competitor for Tiny BASIC back in the 1970's. It really *is* tiny... 768 bytes! Yet it's both faster and more memory efficient than BASIC. Mike Riley wrote a version of it for the 1802, and last night I was using it to run some old VTL programs from the 1970's. Great fun. :-)

Lee

--
A designer knows he has achieved perfection not when there is
nothing left to add, but when there is nothing left to take away.
-- Antoine de Saint Exupery
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

--
This email has been checked for viruses by Avast antivirus software.

Dynamic ram refresh is in all the Z80 flavor s (Z80, Z180,Z280...).
I have a paper done by Tim Olmstead on how to use refresh and
make it work.? ?I'll have to put that in the files area.

FYI the worst example of its use were some S100 memory cards
and the early TRS80 console. All cases it was trying to either
attempting to cheap out or lack of understanding of Drams and
also Z80.? ?These days Static Ram in the 32k (61256) or 64K (61512)
sizes is the end all solution.? That is especially true when using the
faster than 4mhz z80s.

On Mon, May 10, 2021 at 02:06 PM, ajparent1/kb1gmx wrote:

For me its 44 years of z80 and still running.

Wow Allison I read your use of the z80. Its so cool to read that, as well as the fact that its still running for that processor. Im already hooked onto it. Yea I was a 6502 guy from way back and still like it. I think because of the lack of time in my past I let go more interesting micro's like the Z80. So true about its availability to this day. I am going to really like re discovering that micro all over again and even more now.


On Mon, May 10, 2021 at 02:12 PM, Lee Hart wrote:

Mike Riley wrote a version of it for the 1802, and last night I was using it to run some old VTL programs from the 1970's. Great fun. :-)

I heard it was small but wow thats is tiny. I have been playing around with it too Lee and its a bit cryptic (as I have been a C programmer for years, so really.... what is cryptic, lol) but it is really fun to run on the 1802. VTL2 seems to be a really cool little program! I was so fascinated to see it was faster than Pilot too.

On Mon, May 10, 2021 at 11:12 AM, Lee Hart wrote:

I too still have all my old Byte, Dr.Dobbs, REMark, Sextant, QST, etc. magazines, and often go on "archeological digs" for information and entertainment.

Lee,
You are far from alone on that.? I have maybe a dozen boxes of those?that
I've retained over the years.??They tend to reflect my interest in 8080/8085/z80
and other cpus of the day especially software of all forms.

Byte, Kilobaud,? DDobbs, S100 Micrcomputing, Microcomputing, QST (also
my interests with radio), Ham Radio, and Popular Electroncs and Radio Electronics.

VTL, that was an interesting beast.? It was when people were doing TinyBasic
and other small languages.? Often the goal was fit it in a 1k or 2K eproms
(2708 and 2716 in the day)? I morphed VTL into a command line monitor
as a somewhat primitive script language and operating environment.??

VFL was not somuch fast as strikingly compact.? Less code more speed.


Allison

ajparent1/kb1gmx wrote:

Lee, You are far from alone on that. I have maybe a dozen boxes of
those that I've retained over the years. They tend to reflect my
interest in 8080/8085/z80 and other cpus of the day especially
software of all forms.
Byte, Kilobaud, DDobbs, S100 Micrcomputing, Microcomputing, QST
(also my interests with radio), Ham Radio, and Popular Electronics and
Radio Electronics.

I think the fascination for me is that I can read these old articles and *understand* them. They were written at a time when everyone was a beginner.

The chips were also more straightforward; the datasheets might be only a dozen pages.

Today, the computer journals are so obtuse that I can't make any sense of them. And the datasheets have become 1000-page incomprehensible monsters.

VTL, that was an interesting beast. It was when people were doing
TinyBasic and other small languages. Often the goal was fit it in a
1k or 2K eproms (2708 and 2716 in the day). I morphed VTL into a
command line monitor as a somewhat primitive script language and
operating environment.
VTL was not so much fast as strikingly compact. Less code more
speed.

For those who might be interested, VTL is an interpreter (like BASIC). The manual for it is here:



VTL took the "everything is an expression" route. Every line is of the form "line# variable=expression". All the letters A-Z are variables; but so are many of the punctuation symbols. But the punctuation symbols are "system variables" that do extra things. For example, ? is print, # is the next line#, * is end of memory, & is start of memory, etc. So...

#=number is your GOTO line#. #=1 runs the program from the beginning.
&=0 is clear program, because it sets the program size to zero.
*=0 exits VTL, by setting its size to zero.

IF is accomplished by a calculated GOTO. 0 is an illegal line#, so you can't GOTO it. So

20 #=(X=25)*50 means GOTO line 50 if X=25; else continue to the next line.

! is the last line#+1. So RETURN is #=! (GOTO the last line of the caller).

Peculiar; but it works!

Lee
--
A designer knows he has achieved perfection not when there is
nothing left to add, but when there is nothing left to take away.
-- Antoine de Saint Exupery
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com

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This email has been checked for viruses by Avast antivirus software.

On Mon, May 10, 2021 at 04:19 PM, Lee Hart wrote:

For those who might be interested, VTL is an interpreter (like BASIC). The manual for it is here:

Thanks for the pdf Lee!