RetroBrew Computers Forum
Discussion forum for the RetroBrew Computers community.

Home » RBC Forums » General Discussion » Interested in a Z280 SBC (Z280 SBC retrobrew (CPU280 Revival))  () 1 Vote
Re: Interested in a Z280 SBC [message #6254 is a reply to message #5956] Mon, 15 April 2019 13:58 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
Messages: 80
Registered: January 2017
Location: germany
Member
Now as I change the old Z280 the CPU280 run into the config prompt and then booted from ROM.
I have a second CPU280 from the past and even replaced the roms as the boot rom needs an update.

I tried to connect to the floppy drives A=3.5 HD B=5.25 HD on both boards but run into problems.

I got always a "Drive Not Ready" answer but knew that the drives work well. I used them the last weeks
with an Prof-80 and a Prof-180X board successfully. I added 2 pictures with prof boards for information only.

/forum/index.php?t=getfile&id=1330&private=0
/forum/index.php?t=getfile&id=1331&private=0

/forum/index.php?t=getfile&id=1332&private=0


/*-----
fritz
-----*/

[Updated on: Mon, 15 April 2019 14:50]

Report message to a moderator

Re: Interested in a Z280 SBC [message #6260 is a reply to message #6254] Fri, 19 April 2019 01:53 Go to previous messageGo to next message
hperaza is currently offline  hperaza
Messages: 68
Registered: March 2017
Member
fritzeflink wrote on Mon, 15 April 2019 13:58
I tried to connect to the floppy drives A=3.5 HD B=5.25 HD on both boards but run into problems.

I got always a "Drive Not Ready" answer but knew that the drives work well. I used them the last weeks
with an Prof-80 and a Prof-180X board successfully. I added 2 pictures with prof boards for information only.

How did you connect the drives (which cable, adapter, etc.)? The wiring of the floppy connector of the CPU280 is not compatible with standard PC floppy cables (you may already know that). Nevertheless, with a PC cable you can connect a single drive which will appear as B:, not A:.

Also, do the motors start spinning, do the drives' light turn on, do they give any sign of life? If e.g. the motor works, then the problem could be related to the data transfer rate (wrong or bad crystal, faulty controller, etc.), else is a drive select problem (cable or even drive jumper settings). Also make sure that the drives get enough power, especially +12V.

Re: Interested in a Z280 SBC [message #6263 is a reply to message #6260] Mon, 22 April 2019 08:20 Go to previous messageGo to next message
hperaza is currently offline  hperaza
Messages: 68
Registered: March 2017
Member
Version 4.1 of ZSM4 has been just released, which fixes the following minor issues:

  • A second occurrence of an ELSE inside the same IF now produces an error.
  • Fixed a bug in COMMON segment selection.
  • If an invalid option switch is specified on the command line, an error message is displayed and the command is aborted.
Also, a new set of conditional operators has been added: IFZ80, IFZ180 and IFZ280. They may be useful in include files that generate code or define constants depending on the processor type selected by the top-level file.

Since a promise made is a debt unpaid, the full sources have been published at GitHub and will soon be made available via SourceForge as well.

This is a final release (no longer a beta), since the assembler is now practically complete and stable. The very few minor retouches remaining here and there will be polished as time permits.

[Updated on: Tue, 23 April 2019 03:37]

Report message to a moderator

Re: Interested in a Z280 SBC [message #6264 is a reply to message #6263] Mon, 22 April 2019 08:25 Go to previous messageGo to next message
lowen is currently offline  lowen
Messages: 226
Registered: August 2016
Location: Western NC USA
Senior Member
Fritz:
Glad to see the CPU280 booting up from EPROM at least! That's an improvement from before.

Hector:
Glad to see the sources for ZSM4; many many thanks for all the work on it!


--
Bughlt: Sckmud
Shut her down Scotty, she's sucking mud again!
Re: Interested in a Z280 SBC [message #6265 is a reply to message #6263] Mon, 22 April 2019 15:57 Go to previous messageGo to next message
agn453 is currently offline  agn453
Messages: 68
Registered: June 2018
Location: Newcastle, NSW, Australia
Member
hperaza wrote on Tue, 23 April 2019 01:20
Version 4.1 of ZSM4 has been just released, which fixes the following minor issues:



  • A second occurrence of an ELSE inside the same IF now produces an error.

  • Fixed a bug in COMMON segment selection.

  • If an invalid option switch is specified on the command line, an error message is displayed and the command is aborted.
Also, a new set of conditional operators has been added: IFZ80, IFZ180 and IFZ280. They may be useful in include files that generate code or define constants depending on the processor type selected by the top-level file.

Since a promise made is a debt unpaid, the full sources have been published at GitHub and will soon be made available via SourceForge as well.

This is a final release (no longer a beta), since the assembler is now practically complete and stable. The very few minor retouches remaining here and there and will be polished as time permits.

Hector - You're a champion!

Thank you for your rather considerable efforts with ZSM4. They have greatly assisted many of us that are tinkering with the Zilog Z80/Z180/Z280 systems.

Much appreciated.

Tony


--
Tony Nicholson
Re: Interested in a Z280 SBC [message #6269 is a reply to message #6263] Wed, 24 April 2019 16:20 Go to previous messageGo to next message
Wayne W is currently offline  Wayne W
Messages: 385
Registered: October 2015
Location: Fallbrook, California, US...
Senior Member
hperaza wrote on Mon, 22 April 2019 08:20
Version 4.1 of ZSM4 has been just released

This is a final release (no longer a beta), since the assembler is now practically complete and stable. The very few minor retouches remaining here and there will be polished as time permits.

I have updated the CPU280 GitHub repository at https://github.com/wwarthen/CPU280 with this latest release of ZSM4. Note that the repository has two branches. The "master" branch is based on the original toolset and the "zsm" branch is based on ZSM4. I ran a build with the new version and the binary results were identical, so there are no corresponding updates to resultant binaries.

-Wayne
Re: Interested in a Z280 SBC [message #6388 is a reply to message #5749] Tue, 11 June 2019 16:38 Go to previous messageGo to next message
agn453 is currently offline  agn453
Messages: 68
Registered: June 2018
Location: Newcastle, NSW, Australia
Member
agn453 wrote on Sun, 16 December 2018 14:02
plasmo wrote on Sun, 16 December 2018 00:35
WOW, Wow, wow! This is major cool! I'm dropping everything...

Edit:
I ran into two obstacles: Disk Utility does not seem to erase directories. Perhaps my version is too old (v7.Cool, I think you'd mentioned v8.8 but I'm not able to locate it. Alternatively, I can just fill a 64meg CF disk with 0xE5, but that's such a kluge...
I've just added DU v8.8 and NULU 1.52 to the https://github.com/agn453/Z280RC repositry in the utilities folder (DU.COM and NULU.COM). I'll have to go looking to find the original distribution kits (with documentation) for these and put them up too.

While searching through some of my 8" floppy images today - I found the source distribution of DU v8.8 (the Ward Christensen Disk Utility - dated July 1984).

This is the one I've been using to poke around the disk sectors of any disk that's supported by the BIOS of CP/M 1.4, 2.2 and CP/M-Plus since way back when!

I've added DU-V88.LBR to my GitHub at https://github.com/agn453/Z280RC in the utilities sub-directory and attached to this message. Extract the contents with your favourite library utility.

Better late than never!

Tony

PS: I have later edits too but they're not so universal (e.g. DU V9.0 only works under CP/M Plus).
  • Attachment: DU-V88.LBR
    (Size: 77.25KB, Downloaded 444 times)


--
Tony Nicholson
Re: Interested in a Z280 SBC [message #6814 is a reply to message #6388] Mon, 18 November 2019 21:34 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
Messages: 80
Registered: January 2017
Location: germany
Member
Hi...

trying to answer some questions I found the source for the

IDE Festplatten-Utility V0.2 TR 151192.

As I named the files idetest.com I didn't remember which version it is.
I didn't try the com file so you may better compile the source.

For adding an ide harddisk there was a short description for version 1.1 for fast reading.



/*-----
fritz
-----*/

[Updated on: Mon, 18 November 2019 21:36]

Report message to a moderator

Re: Interested in a Z280 SBC [message #6884 is a reply to message #6814] Sun, 22 December 2019 11:53 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
Messages: 80
Registered: January 2017
Location: germany
Member
Hi...

For January 2nd 2020 I will take oldcomputers-ddns.org offline for personal reasons and will not open it again.

So long and thanks for all the fish.


/*-----
fritz
-----*/
Re: Interested in a Z280 SBC [message #6886 is a reply to message #6884] Mon, 23 December 2019 00:07 Go to previous messageGo to next message
agn453 is currently offline  agn453
Messages: 68
Registered: June 2018
Location: Newcastle, NSW, Australia
Member
Fritz,

Thank you for your valuable contributions to the Retro-computing hobby.

I just checked the wayback machine at https://archive.org and see only some of the pages and text has been captured (for posterity). Some of your material (particularly the Z280 stuff) has been very useful to me and I trust it will be preserved for the future.

Tony


--
Tony Nicholson
Re: Interested in a Z280 SBC [message #6887 is a reply to message #6886] Mon, 23 December 2019 01:57 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
Messages: 80
Registered: January 2017
Location: germany
Member
No, oldcomputers should not be archived on wayback but there are some mirrors.

archive.sundby.com/mirror/oldcomputers.dyndns.org
www.z80cpu.eu/mirrors/oldcomputers.dyndns.org



/*-----
fritz
-----*/

[Updated on: Mon, 23 December 2019 02:48]

Report message to a moderator

Re: Interested in a Z280 SBC [message #6888 is a reply to message #6887] Mon, 23 December 2019 06:45 Go to previous messageGo to next message
lowen is currently offline  lowen
Messages: 226
Registered: August 2016
Location: Western NC USA
Senior Member
Fritz, as I've said a few times already, thanks so much for your archive; it's greatly helped me over the years!

--
Bughlt: Sckmud
Shut her down Scotty, she's sucking mud again!
Re: Interested in a Z280 SBC [message #6890 is a reply to message #6888] Mon, 23 December 2019 14:40 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
Messages: 80
Registered: January 2017
Location: germany
Member
There must be no hurry as I was told some friends from the https://www.classic-computing.org/ will spend some place on their server
for oldcomputers-ddns but I will have less time to help them.

I wish all a Merry Christmas and a Happy New Year.


/*-----
fritz
-----*/

[Updated on: Thu, 26 December 2019 03:23]

Report message to a moderator

Re: Interested in a Z280 SBC [message #6892 is a reply to message #6890] Mon, 23 December 2019 15:22 Go to previous messageGo to next message
Wayne W is currently offline  Wayne W
Messages: 385
Registered: October 2015
Location: Fallbrook, California, US...
Senior Member
Hi Fritz,

Just want to add my personal thanks for the work you have done over time to maintain your archive. It was a critical resource for me. I am glad to hear it will have a new home.

-Wayne
Re: Interested in a Z280 SBC [message #6894 is a reply to message #6892] Thu, 26 December 2019 11:40 Go to previous messageGo to next message
etchedpixels is currently offline  etchedpixels
Messages: 333
Registered: October 2015
Senior Member
Ditto - some of the Video Genie stuff was pretty much essential for emulator hacking
Re: Interested in a Z280 SBC [message #6896 is a reply to message #6894] Thu, 26 December 2019 14:20 Go to previous messageGo to next message
etchedpixels is currently offline  etchedpixels
Messages: 333
Registered: October 2015
Senior Member
Is there a particular reason you have it blocked from archive.org ?

Re: Interested in a Z280 SBC [message #6958 is a reply to message #6896] Mon, 27 January 2020 11:46 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
Messages: 80
Registered: January 2017
Location: germany
Member
etchedpixels wrote on Thu, 26 December 2019 23:20
Is there a particular reason you have it blocked from archive.org ?

Yes, but oldcomputers-ddns.org has a new place.




/*-----
fritz
-----*/
Re: Interested in a Z280 SBC [message #6982 is a reply to message #6958] Sat, 01 February 2020 05:36 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
Messages: 80
Registered: January 2017
Location: germany
Member
oldspark is now a new member of this forum.

He even has a CPU280 and always new ideas what to do with it.

I'm fighting with html @ the moment ... Crying or Very Sad
https://www.retrobrewcomputers.org/forum/index.php?t=msg& ;amp ;th=2&goto=6979&#msg_6979


and what ideas he has..


/*-----
fritz
-----*/

[Updated on: Sat, 01 February 2020 05:48]

Report message to a moderator

Re: Interested in a Z280 SBC [message #6983 is a reply to message #1189] Sat, 01 February 2020 08:21 Go to previous messageGo to next message
oldspark is currently offline  oldspark
Messages: 21
Registered: January 2020
Junior Member
I'm here Fritz Smile

Regards,

Holm

[Updated on: Sat, 01 February 2020 09:14]

Report message to a moderator

Re: Interested in a Z280 SBC [message #7841 is a reply to message #6983] Tue, 30 June 2020 00:10 Go to previous messageGo to next message
agn453 is currently offline  agn453
Messages: 68
Registered: June 2018
Location: Newcastle, NSW, Australia
Member
Bill Shen has graciously provided me with a QuadSer 4-port UART module (using the Oxford Semiconductor OX16C954 rev B chip) to try out with my Z280RC board.

I've just updated my CP/M Plus BIOS for the Z280RC to add polled I/O support for this module.

You'll find the latest BIOS files with this support and documentation on my GitHub at

https://github.com/agn453/Z280RC

I'll add interrupt support and CP/M Plus DEVICE command support for the higher baud rates soon.

Tony


--
Tony Nicholson
Re: Interested in a Z280 SBC [message #7843 is a reply to message #7841] Tue, 30 June 2020 13:11 Go to previous messageGo to next message
dittman is currently offline  dittman
Messages: 9
Registered: February 2019
Junior Member
agn453 wrote on Tue, 30 June 2020 00:10
Bill Shen has graciously provided me with a QuadSer 4-port UART module (using the Oxford Semiconductor OX16C954 rev B chip) to try out with my Z280RC board.

I've just updated my CP/M Plus BIOS for the Z280RC to add polled I/O support for this module.

You'll find the latest BIOS files with this support and documentation on my GitHub at

(I can't include links)

I'll add interrupt support and CP/M Plus DEVICE command support for the higher baud rates soon.

Tony
That would be neat.

Bill, do you sell the QuadSer boards?
Re: Interested in a Z280 SBC [message #7844 is a reply to message #7843] Tue, 30 June 2020 16:04 Go to previous messageGo to next message
plasmo is currently offline  plasmo
Messages: 916
Registered: March 2017
Location: New Mexico, USA
Senior Member
Well, I was giving them away, but I suppose I should sell them for $20 to cover postage and some part cost. OK, $20 to USA locations.
Bill
PS, this is the QuadSer modified for Z280RC: https://www.retrobrewcomputers.org/doku.php?id=builderpages: plasmo:quadser:ec4z280rc

[Updated on: Tue, 30 June 2020 16:07]

Report message to a moderator

Re: Interested in a Z280 SBC [message #7848 is a reply to message #7841] Wed, 01 July 2020 23:10 Go to previous messageGo to next message
agn453 is currently offline  agn453
Messages: 68
Registered: June 2018
Location: Newcastle, NSW, Australia
Member
agn453 wrote on Tue, 30 June 2020 17:10
Bill Shen has graciously provided me with a QuadSer 4-port UART module (using the Oxford Semiconductor OX16C954 rev B chip) to try out with my Z280RC board.

I've just updated my CP/M Plus BIOS for the Z280RC to add polled I/O support for this module.

You'll find the latest BIOS files with this support and documentation on my GitHub at

https://github.com/agn453/Z280RC

I'll add interrupt support and CP/M Plus DEVICE command support for the higher baud rates soon.

Tony
DEVICE command support was relatively easy. I just modified the CP/M Plus DEVICE.PLM source file, compiled it under ISIS emulation into a new DEVICE.COM; also I updated HELP.HLP file with the changes documented.

(hint: HELP DEVICE .OPTIONS after you get it copied over to your CP/M-Plus boot disk).

The GitHub repository has it all!

Interrupt support will take more time though...

Tony


--
Tony Nicholson
Re: Interested in a Z280 SBC [message #8078 is a reply to message #7848] Mon, 09 November 2020 04:47 Go to previous messageGo to next message
plasmo is currently offline  plasmo
Messages: 916
Registered: March 2017
Location: New Mexico, USA
Senior Member
I wrote about an intermittent transmission of spurious character with Z280's internal UART, https://www.retrobrewcomputers.org/forum/index.php?t=msg& ;th=403&goto=8077&#msg_8077

I've done similar test with Z280RC and confirm the spurious character output is not a problem for Z280RC; it is not because Z280RC is operating in 16-bit mode vs 8-bit mode for ZZ80MB; it is because Z280RC's UART clock is derived from Z280's CPU clock through a divider in CPLD. Because UART clock is synchronous to CPU clock, there is no metastability problem. To demonstrate that, I modified a Z280RC board to have an independent 1.8432MHz clock and with that modification it also intermittently put out spurious character.

I can now put this particular issue to bed; the bottom line is UART clock MUST be synchronous to CPU clock.

Bill
Re: Interested in a Z280 SBC [message #8380 is a reply to message #1189] Wed, 10 March 2021 06:22 Go to previous messageGo to next message
will is currently offline  will
Messages: 213
Registered: October 2015
Senior Member
Hello retrobrewers!

I have been building a CPU-280 board recently, having received a very generous donation of PCBs and parts. I have some queries.

Firstly, the floppy interface. I've soldered a 34-pin header to the last 34 pins of CN2, pins 17-50, the 34 pins closest to the RTC chip with pin 1 on my header being pin 17 on CN2. I found I then had to make up an adapter to convert this to a standard PC floppy cable. The adapter has two 34-pin headers: An input which connects to the CPU-280 with a straight through cable, and an output which connects to a standard PC floppy cable with two drives as A: (before the twist) and B: (after the twist). On the output header I removed pin 3, which was blocked off on several of the cables I have as a keying pin. This seems to have worked for me but could someone please check it is correct? If it is correct I will add it to the cpu280 board page in the Wiki.

INPUT       ->  OUTPUT
CPU-280 CN2     PC floppy       Signal name
34 (50) pin     34 pin

2  (18)         n/c             RWC/RPM
4  (20)         2               DENSITY (0=HIGH, 1=LOW)
6  (22)         n/c             DS3
8  (24)         8               INDEX
10 (26)         12              DS0 / DSB
12 (28)         14              DS1 / DSA
14 (30)         n/c             DS2
16 (32)         10, 16          MOTOR ON 
18 (34)         18              DIRECTION
20 (36)         20              STEP
22 (38)         22              WRITE DATA
24 (40)         24              WRITE GATE
26 (42)         26              TRACK0
28 (44)         28              WRITE PROTECT
30 (46)         30              READ DATA
32 (48)         32              SIDE (HEAD) SELECT
34 (50)         34              DISK CHANGE
ALL ODD         ALL ODD         GROUND
Secondly, the memory timing. The CPU-280 manual says to measure the CAS pulse width and adjust the value of C6 to get the CAS pulse width to 20ns. Page 22 of this document shows a timing diagram. My interpretation is that I need to look at the width of the positive pulses on one of the /CAS lines during a burst memory access, as shown in the third diagram, "Burst-Speicherzugriffe (RAM)". To test this I probed pin 17 on the Z280CAS4 GAL (/CAS for DRAM ICs 11 and 12) while MBASIC.COM ran an infinite loop (something to keep the CPU busy that wouldn't fit in cache). This is what I am seeing:

/forum/index.php?t=getfile&id=2004&private=0

This looks mostly OK to me, the lower (zoomed in) trace shows upward pulses are about 20ns and the low pulses between them are about 60ns. Is this what I'm looking for? The upper trace (zoomed out) does not quite match the timing diagram, which shows CAS going low again at the start of cycle 7, while it remains high on my scope trace. If this is confirmed as OK I might update the wiki page with the above notes on how to measure this and my scope trace for reference.

Finally, the REH-IDE interface. I have this working with the IDETEST.COM program, it can talk to a compact flash card connected to the board. My drive CHS geometry is 31045/16/63 (which I expect is very similar to most large modern drives). If I update "hard.280" in the seemingly obvious way to set up four 65-cylinder partitions (just under 32MB each), and adjust the DPBs, then I get an error when GENCPM runs ("Unable to allocate space for hash table"). If I make some of the partitions smaller then any attempt to access the partitions from CP/M just hangs the machine. I've filled the first few hundred megs of the CF card with 0xE5 bytes.

Can anyone point me at an example modified "hard.280" and/or documentation on what GENCPM wants from me?

Edit 2021-03-13: I figured it out and have the IDE interface working fine now :)

Thanks everyone

Will

[Updated on: Sat, 13 March 2021 07:03]

Report message to a moderator

Re: Interested in a Z280 SBC [message #8895 is a reply to message #8380] Fri, 23 July 2021 11:18 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
Messages: 63
Registered: May 2017
Member
Hi, all. I've finally gotten around to digging out my CPU280 and IDE and mounted them in a backplane with power supply. The system is working fine with a 3.5" floppy drive, but I really wanted to use it with a Gotek / FlashFloppy emulator as drive A:. Unfortunately, it's not cooperating. The system boots and starts accessing the drive image, but invariably dies with an I/O error while looking for PROFILE.SUB. Does anyone know why the CPU280 works with a real drive but not a Gotek? I had previously used with an HxC 2001 device and had no problem at all.

Update: A Gotek with HxC firmware gets me a lot further, but eventually crashes.

SOLVED: Apparently the CPU280 requires a drive with 'IBM PC' behavior and pinout. The default for F-F firmware is 'Shugart' and jumper JC must be inserted to get PC compatibility. With that done, it's working properly. Hope this helps someone.

[Updated on: Fri, 23 July 2021 12:41]

Report message to a moderator

Re: Interested in a Z280 SBC [message #9137 is a reply to message #8895] Sat, 18 September 2021 13:29 Go to previous messageGo to next message
hperaza is currently offline  hperaza
Messages: 68
Registered: March 2017
Member
Hi all,

Just mentioned in a new topic that a Z280 CPU emulator is now available, written by Michel Tomek: https://github.com/mtdev79/z280emu. Hardware emulation for Plasmo's amazing Z280RC is included, and support for the CPU280 hardware is planned.

Hector.
Re: Interested in a Z280 SBC [message #10167 is a reply to message #1189] Sat, 26 November 2022 10:25 Go to previous messageGo to next message
hperaza is currently offline  hperaza
Messages: 68
Registered: March 2017
Member
RSX280 is (finally) running on the CPU280! Smile There is a 3.5" 1.44M floppy image available on github. Only floppy disks are supported at this moment, GIDE disk drivers will be added next. Due to a limitation of the CPU280 ROM, CP/M needs to be booted first, and then RSX280 booted from CP/M.


[Updated on: Sat, 26 November 2022 10:27]

Report message to a moderator

Re: Interested in a Z280 SBC [message #10169 is a reply to message #10167] Mon, 28 November 2022 18:35 Go to previous message
lowen is currently offline  lowen
Messages: 226
Registered: August 2016
Location: Western NC USA
Senior Member
This is fantastic, hperaza!

--
Bughlt: Sckmud
Shut her down Scotty, she's sucking mud again!
Previous Topic: New TI Project
Next Topic: Z180 upd7220 GDC SBC


Current Time: Sat Mar 15 20:35:04 PDT 2025

Total time taken to generate the page: 0.01525 seconds