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Home » RBC Forums » General Discussion » Interested in a Z280 SBC (Z280 SBC retrobrew (CPU280 Revival))  () 1 Vote
Re: Interested in a Z280 SBC [message #2299 is a reply to message #2246] Sat, 08 April 2017 11:43 Go to previous messageGo to next message
Jonas is currently offline  Jonas
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I just had to test a few of my 5,25 inch HD drives. I formatted the media with format #47 and tested copying from drive a: (3,5 inch) to drive b: (5,25 inch). No problems at all, only the normal noise!

[Updated on: Sat, 08 April 2017 11:43]

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Re: Interested in a Z280 SBC [message #2474 is a reply to message #2299] Wed, 19 April 2017 20:38 Go to previous messageGo to next message
computerdoc is currently offline  computerdoc
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Hi Guys,
I'm interested in building a Z280 board. Is there an extra PCB available. I started reading this thread from the beginning and reached Page 2 When I realized I have to go to bed so I thought I would ask. Also is there a wiki page on this project or do I need to continue downloading all the attachments. The Z280 seems to be of interest to a lot of builders. I'll continue to read. Take care my friends.


Kip Koon
computerdoc at sc dot rr dot com
http://www.cocopedia.com/wiki/index.php/User:Computerdoc
Re: Interested in a Z280 SBC [message #2475 is a reply to message #1189] Wed, 19 April 2017 20:53 Go to previous messageGo to next message
Andrew B is currently offline  Andrew B
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There's no wiki page on this since the CPU280 is a legacy non-RBC design, but if the people testing these new CPU280 boards would like a wiki page to collect up all of the information in one place - I'd be happy to create one and put an appropriate note at the top regarding the history of the design.
Re: Interested in a Z280 SBC [message #2480 is a reply to message #2475] Thu, 20 April 2017 06:28 Go to previous messageGo to next message
lowen is currently offline  lowen
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Andrew B wrote on Wed, 19 April 2017 23:53
There's no wiki page on this since the CPU280 is a legacy non-RBC design, but if the people testing these new CPU280 boards would like a wiki page to collect up all of the information in one place - I'd be happy to create one and put an appropriate note at the top regarding the history of the design.

Andrew, that would be fantastic. I have intended for a while to create a wiki page for it, but work and family have conspired to reduce my time availability since early March.

computerdoc wrote on Wed, 19 April 2017 23:38
Hi Guys,
I'm interested in building a Z280 board. Is there an extra PCB available. I started reading this thread from the beginning and reached Page 2 When I realized I have to go to bed so I thought I would ask. Also is there a wiki page on this project or do I need to continue downloading all the attachments. The Z280 seems to be of interest to a lot of builders. I'll continue to read. Take care my friends.


I have some boards and parts; PM me and I'll get you on the list.

Status Update:
Work and family commitments have been overwhelming since early March. I plan to burn and test several sets of GAL16V8s and 27C512 EPROMs Saturday. I'm using '512s because that is what I have available in quantity. I will be setting my test bench back up after an office remodel that started the last week of February, and will be testing Z280s and FDCs. At that point I'll be able to start filling orders again.





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[Updated on: Thu, 20 April 2017 06:33]

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Re: Interested in a Z280 SBC [message #2656 is a reply to message #2480] Sat, 06 May 2017 13:48 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
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Hi...

I just managed to get CP/M+ (CP/M 3.0) running with MYZ80 under OS/2. In this case it is the OS/2 version ECS 2.1
running under VirtualBox on Win8.1/64.
After printing the "Using CP/M 3.0 with MYZ80" I changed my mistakes and wanted to make the CPU280 system files. I send
the old original CPU280 to Tilmann for repairing but don't know if this is possible.
When I get the card from Lamar I want to be "up to date" with the system as it's long ago I had one and so I had some interesting hours. Very Happy

index.php?t=getfile&id=408&private=0






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Re: Interested in a Z280 SBC [message #2683 is a reply to message #2656] Mon, 08 May 2017 10:00 Go to previous messageGo to next message
lowen is currently offline  lowen
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Status update, 5/8/2017:

I am caught up on paid-for orders. I would like to verify 27C512 operation with my CPU280 before opening up to orders again, and I expect to work on that next week while I'm on vacation. If you've expressed interest already, I have your name and will start getting with you soon. I am so sorry for the delays, but we had an unforeseen change here at work that dramatically increased my work hours for a while. I can also report that we have another builder who has his board built, but not yet fully operational, who is waiting for forum access and who will likely have questions. I'm trying to contact people in the order that they originally contacted me, by the way.

So, I thank you for your patience!


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Bughlt: Sckmud
Shut her down Scotty, she's sucking mud again!
Re: Interested in a Z280 SBC [message #2703 is a reply to message #2683] Tue, 09 May 2017 13:33 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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The owner of that newly-built board is me. Hello, all! At this point, I only know that the magic smoke didn't come out of it when I powered up. It's drawing about 430 ma, but that's unfortunately the only sign of life at present. All three LEDs remain on, so it's not initializing properly. I have several things to address, I believe:

- I used 27C512 EPROMs, but Lamar later told me these were not known to work.

- The Dallas 1287 came out of my parts drawer and it's probably 25+ years old and likely dead. Not sure if that would prevent it from running.

- I'm running a Z280 that was purchased from UTSource in China. I picked up a half-dozen, so probably worth swapping it out in case this one's a dud.

- I followed what I thought Tillman was suggesting in terms of building the console serial cable: Crimping 2x 9-pin D connectors on to a 20-pin ribbon. This is probably wrong. But, not an issue at present since the unit isn't showing proper LED status.

Any other suggestions for troubleshooting would be appreciated. I'm sure it will start cooperating sooner or later Smile

-
Re: Interested in a Z280 SBC [message #2704 is a reply to message #2703] Tue, 09 May 2017 14:50 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
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Please ad an external battery to the dallas if you have non running.
I did it and was a short work. There are several instructions how to do that.
http://www.classic-computers.org.nz/blog/2009-10-10-renovati ng-a-dallas-battery-chip.htm


From:
http://oldcomputers.dyndns.org/public/pub/rechner/zilog/z280 /source_from_tilmann_reh/CPU280-Doc/CPU280%20Hardware-Manual %20EN.pdf

The boot loader consists of three modules: One is the basis
for cold starting (initalization and RAM test) and the actual
booting, the other two contain disk-I/O subroutines and the
setup.
After a reset, the first step is to determine the processor
clock frequency (in multiples of 614 kHz), using the real time
clock. After that the console port is initialized (according to the
values stored in the setup; the default is 8+n+1 bits, 9600 baud,
no handshake) and a message is output to the console port. Next
follows the RAM test, which examines the whole addressable
memory for writeability (nondestructive). The available memory
capacity is determined in the same step. If there were no errors
in the RAM test, then the boot loader is copied into RAM and
started there. Further and more detailed hardware diagnostics are
planned, but not implemented yet.
During these operations the three LEDs display the current
status. The hardware reset enables all three LEDs. Immediately
after reset the first one is turned off. The second one is turned
off after successfully measuring the clock frequency, and the
third one after the RAM test.


**** here I didn't know if your non-exist setup makes problems
If the battery in the real-time clock
is empty, the second LED stays on while the third is turned off.


/*-----
fritz
-----*/
Re: Interested in a Z280 SBC [message #2705 is a reply to message #2704] Tue, 09 May 2017 17:41 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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I'm pleased to report that it's alive to large degree! I replaced the 27C512s with 256s and swapped the CPU out while I had a clear shot with the PLCC puller. Then I studied the serial pinout and realized that the D-Sub 9pin was setup for direct connect with a PC serial port. Fired up ProComm on the shop machine and plugged it in pin for pin. This time it did what it was supposed to with the on-board LEDs and started to sign on at the console. It counts memory to '0320' and dies with an error message about not having enough RAM. How should I interpret this? Based on that address, is it seeing DRAM at all?

A lot of things have to be working right to get this far, so I'd call it progress.

Re: Interested in a Z280 SBC [message #2707 is a reply to message #2705] Tue, 09 May 2017 18:14 Go to previous messageGo to next message
Wayne W is currently offline  Wayne W
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It sounds like the memory test is getting to 320K, then failing.

What type of memory did you use?

Make sure that you programmed IC21 (RAM GAL) appropriately for the type of memory you used.

-Wayne
Re: Interested in a Z280 SBC [message #2708 is a reply to message #2707] Tue, 09 May 2017 18:55 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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I installed (4) 512k x 4 ZIPs that came from Lamar and used the Z280CAS4.JED file to program the RAM GAL. My assumption was that '4' meant 4-bit wide memory. Is that not correct?
Re: Interested in a Z280 SBC [message #2709 is a reply to message #2708] Tue, 09 May 2017 19:28 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
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snhirsch_gmail.com wrote on Wed, 10 May 2017 03:55
I installed (4) 512k x 4 ZIPs that came from Lamar and used the Z280CAS4.JED file to program the RAM GAL. My assumption was that '4' meant 4-bit wide memory. Is that not correct?


You can use 256K x 4 or 1M x 4 - I think 512 x 4 is not possible.
Lamar can tell more but if this was used before the Z280CAS.JED and Z280CAS.PDS maybe right.


Hmm.. 4 was written for 4 megabyte chips type.

The core memory of the CPU280 consists of the dynamic RAMs IC11 through IC18. Several different configurations are
possible, using 1 MB and 4 MB chips, organized as 256K x 4 or 1M x 4 (part numbers 514256 or 514400). For space reasons,
and due to the availability of pin-compatibe types, RAM chips in ZIP packages are used.
The smallest configuration contains four 514256 (IC11 through IC14), which yields a capacity of 512 KB. The standard
configuration is eight of these memory chips for a capacity of 1MB. Memory space can be increased to 2 MB and 4 MB by
using four 0r eight 514400 chips. When changing between 256Kx4 and 1Mx4 chips, the programming of IC22 has to be
modified.


I hope I did not misinterprt this.


The Z280CAS4.JED and Z280CAS4.PDS are for 4MB RAM types.


############################################

TITLE CPU280 4-MB-CAS-DECODER IC22
PATTERN 01
REVISION 01
AUTHOR TILMANN REH
COMPANY REHDESIGN
DATE 20.09.1992



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[Updated on: Tue, 09 May 2017 19:50]

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Re: Interested in a Z280 SBC [message #2713 is a reply to message #2709] Wed, 10 May 2017 04:59 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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I was mistaken on the DRAM size. There are (4) TC514400 60ns (1M x 4) chips for a total of 2MB. Since that's not 4MB, would Z280CAS4 still be the correct JEDEC file? Further, 320k seems like an odd place for the count to stop. Can someone with working knowledge of the circuit offer any advice on further debugging?
Re: Interested in a Z280 SBC [message #2714 is a reply to message #2713] Wed, 10 May 2017 05:16 Go to previous messageGo to next message
Wayne W is currently offline  Wayne W
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I think that is the right JEDEC file. I am not sure what would cause it to stop at that point, but definitely check solder joints on the RAM chips.
Re: Interested in a Z280 SBC [message #2715 is a reply to message #2713] Wed, 10 May 2017 05:23 Go to previous messageGo to next message
Jonas is currently offline  Jonas
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Are the DRAMs in sockets or have you soldered them? Contact problem maybe?

I use single-in-line machine tooled strips instead of the hard-to-find sockets. I actually bent one of the pins on one of the chips by accident. Everything is working now, though.
Re: Interested in a Z280 SBC [message #2717 is a reply to message #2713] Wed, 10 May 2017 05:45 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
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As Wayne W wrote - I think that is the right JEDEC file too.

As Tilmann wrote:

Memory space can be increased to 2 MB and 4 MB by using four or eight 514400 chips. When changing between 256Kx4 and 1Mx4 chips, the programming of IC22 has to be
modified.

Have you installed them like JCoffman showed in his picture?
https:// www.retrobrewcomputers.org/forum/index.php?t=getfile&id= 253&

Are this 2MB ?

index.php?t=getfile&id=418&private=0
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[Updated on: Wed, 10 May 2017 05:46]

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Re: Interested in a Z280 SBC [message #2718 is a reply to message #2707] Wed, 10 May 2017 05:55 Go to previous messageGo to next message
Wayne W is currently offline  Wayne W
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Wayne W wrote on Tue, 09 May 2017 18:14

Make sure that you programmed IC21 (RAM GAL) appropriately for the type of memory you used.


Sorry, it is IC22 (CAS GAL) that needs to be switched for the memory chip type (not IC21 RAM GAL).

-Wayne
Re: Interested in a Z280 SBC [message #2719 is a reply to message #2718] Wed, 10 May 2017 10:17 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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Thanks, all! I have installed the DRAM modules as shown in the photo. They are inserted into socket strips. I had some nice wipe-contact SIP strips from another project that appear to make very positive contact with the ZIP package pins. I'll take a very close look at how they are seated and examine the socket strips for cold solder joints. I suppose it's possible that one of the chips is bad, but let me rule out the obvious first.

[Updated on: Wed, 10 May 2017 10:18]

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Re: Interested in a Z280 SBC [message #2720 is a reply to message #2719] Wed, 10 May 2017 10:39 Go to previous messageGo to next message
lowen is currently offline  lowen
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I'll be glad to send four more ZIP chips your way as exchange for the four you have now if the obvious things don't check out.

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Re: Interested in a Z280 SBC [message #2723 is a reply to message #2720] Wed, 10 May 2017 17:32 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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I found something that doesn't look right. After carefully checking for bent pins, cold solder joints, etc. I measured the CAS pulse width at, e.g. pin 19 of the CAS GAL and found it to be 80ns. This really looks off. The timing cap on my board is a 120pf/50V polystyrene cap (the only one of that value I had). Now I'm wondering if that type of capacitor is appropriate for this application. Could the 4x too long pulse width cause the problem I'm seeing?

Update: I accidentally discovered that touching the bottom of the board in the area of C8 (timing cap) would sometimes enable it to get through the entire memory test and present the firmware boot menu before freezing up. Really appears something is wrong with CAS generation.

[Updated on: Wed, 10 May 2017 18:01]

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Re: Interested in a Z280 SBC [message #2731 is a reply to message #2723] Thu, 11 May 2017 05:35 Go to previous messageGo to next message
lowen is currently offline  lowen
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snhirsch_gmail.com wrote on Wed, 10 May 2017 20:32
I found something that doesn't look right. After carefully checking for bent pins, cold solder joints, etc. I measured the CAS pulse width at, e.g. pin 19 of the CAS GAL and found it to be 80ns. This really looks off.


80ns CAS would definitely be a problem.

Quote:

Update: I accidentally discovered that touching the bottom of the board in the area of C8 (timing cap) would sometimes enable it to get through the entire memory test and present the firmware boot menu before freezing up. Really appears something is wrong with CAS generation.


I would double-check R8 and the solder connections at R8 and C6. I can't imagine a poly cap developing a really large series resistance, but it's possible. If R8 and the solder connections for R8 and C6 (and the trace to NCLK to IC21 and IC22) check OK I would change C6 for a 120pF ceramic.

However, it is odd that you're getting exactly 4x 20ns here; can you double-check the timing of the CLK signal at IC22 pin 1 to make sure it's the full-speed clock (jumpers should be set for a 1:1 bus clock)? I don't think it is the problem, especially since you're getting an odd 'gimmick' effect when touching the board, but it can't hurt to check.

The fact that you get text and the firmware setup later is a really good sign; get the CAS timing nailed and I think you'll have it running. But if it looks like bad RAM let me know.


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Re: Interested in a Z280 SBC [message #2734 is a reply to message #2723] Thu, 11 May 2017 11:53 Go to previous messageGo to next message
Jonas is currently offline  Jonas
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I'm using Panasonic ECQB 120pF 50V polyester caps without any issues on two boards. I don't know how polyester caps cope with excessive heat. I was careful and fast when I soldered them.

Edit: After some reading in several soldering guidelines covering film capacitors (polyester, polystyrene et cetera) I found several warnings about excessive heat for prolonged periods. I guess it's quite easy to cause permanent damage or changed parameters including the capacitance.

[Updated on: Thu, 11 May 2017 12:35]

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Re: Interested in a Z280 SBC [message #2747 is a reply to message #2734] Thu, 11 May 2017 16:12 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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I continued probing around with the scope. IC22 (CAS GAL) is getting the full clock speed on pin 1 and I have the divider jumpers correct for 1:1. Here's the interesting part: I'm seeing an inverted pulse that's about 20ns wide at pin 3 of IC30 (Q\), but only sporadic noise at pin 2 (Q). Same thing for pins 10 and 11: 11 shows output, but 10 has only random bursts. The only way I can reason for one complementary output to be dead is if something is loading down the dead outputs. I pulled both IC21 and 22, read them back in the programmer and both of them show the correct checksum. At this point, I'm stumped.
Re: Interested in a Z280 SBC [message #2748 is a reply to message #2747] Thu, 11 May 2017 18:35 Go to previous messageGo to next message
lowen is currently offline  lowen
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Hmm. IC30 and part of IC4 are the core of the memory timing chain for burst mode, and are critical. Which part are you using for this? The parts list calls for a 74ACT175 or a 74AS175; what part are you using? Q and /Q should be complementary, for sure, but to load that down should show up as extra heat or abnormally high supply current spikes. Can you scope the power supply and see if the supply voltage shows spikes, to see if it's heavily loaded? What about pins 6 and 7 of IC30, and pins 8 and 9 of IC4?

The waveforms should look like what is shown on page 22 of the German z280_reh.pdf I sent (and am attaching to this reply for everyone else's benefit).

It's possible you have a short or two somewhere; are IC4 and IC30 socketed? You could, very carefully and on the lowest range of you meter, check the resistance of those pins to ground and Vcc (with the IC21 and IC22 out of their sockets). I say the lowest range of your meter, since that is where the typical ohmmeter puts out the lowest voltage. It's possible that the short is in the board itself, or a very small solder bridge is lurking. Tilmann's original run of boards had a few with shorted traces and vias, and mine certainly could have similar issues. I am not in my office to where I can check right now to see, but next week I'll spend some quality time with a few of the bare boards and my USB microscope and see if I see anything amiss in the trace running between IC4, IC30, IC21, IC22, and the RAM array.

EDIT: And if this wasn't a new 74ACT175 you might want to try another one, just in case. I have had new chips be bad before, but I have run into many more parts box dead chips in my experimenting.

Hope that helps.
  • Attachment: z280_reh.pdf
    (Size: 1.37MB, Downloaded 400 times)


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[Updated on: Thu, 11 May 2017 18:37]

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Re: Interested in a Z280 SBC [message #2755 is a reply to message #2748] Fri, 12 May 2017 05:08 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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Thanks, Lamar. I'll check the items you suggest. I'm using an ACT175 and have already swapped parts for both that IC and the '74.

I looked closely at the waveform diagram. The /CAS waveform on my board is what appears as "refresh" on that sheet. I have never seen the narrow positive-going pulses shown in the burst-mode section. Clearly my problems center on the burst-mode subsystem. I'm actually surprised the board shows as much life as it does given how far off the timing is.

If nothing turns up from probing the power supply connections, I'll put my logic analyzer on it and try to capture a complete picture with all the timing signals. As you can probably see, I have a lot of nice tools here but not necessarily the hardware smarts to match Smile.
Re: Interested in a Z280 SBC [message #2756 is a reply to message #2755] Fri, 12 May 2017 17:27 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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At worst I see perhaps 40mv of ground bounce, nothing visible on 5V rail. Checked the /CAS waveform again, stretching it out to make burst pulses more obvious. Watching carefully during the abbreviated memory test I see none. The only activity on /CAS is a train of 80ns wide negative-going pulses as shown in the 'reset' diagram.

Tomorrow I'm going to start checking continuity point to point between sockets. Verifying that something is connected from point A to point B is the easy part. Checking to see if it's accidentally shorted to other points presents more of a challenge. Somewhere I have a software tool that can print Gerber files on a laser printer. If I had the layout next to me on the bench I could narrow the search for shorts quite a bit. Is it possible someone on the list already has a PDF of PCB front and rear?
Re: Interested in a Z280 SBC [message #2757 is a reply to message #2756] Fri, 12 May 2017 22:19 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
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snhirsch_gmail.com wrote on Sat, 13 May 2017 02:27
If I had the layout next to me on the bench I could narrow the search for shorts quite a bit. Is it possible someone on the list already has a PDF of PCB front and rear?



Here I have a scan from an old printed layout.

Parts side: please load the file from this link
http://oldcomputers.dyndns.org/public/pub/rechner/zilog/z280 /my_old_Z280/pictures/CPU280_A_layout_A4_print.jpg

Solder side: please load the file from this link
http://oldcomputers.dyndns.org/public/pub/rechner/zilog/z280 /my_old_Z280/pictures/CPU280_B_layout_A4_print.jpg


EXAMPLE:

CPU280_A_layout Parts side
index.php?t=getfile&id=422&private=0

CPU280_B_layout Solder side
index.php?t=getfile&id=424&private=0

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[Updated on: Sat, 13 May 2017 07:46]

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Re: Interested in a Z280 SBC [message #2759 is a reply to message #2757] Sat, 13 May 2017 06:20 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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Thanks, Fritz! That is a big help.
Re: Interested in a Z280 SBC [message #2760 is a reply to message #2759] Sat, 13 May 2017 07:48 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
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snhirsch_gmail.com wrote on Sat, 13 May 2017 15:20
Thanks, Fritz! That is a big help.


I hope but that's an old print.

Please load the files from the link in my post - the pictures shown in the post are small and for information only..


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Re: Interested in a Z280 SBC [message #2761 is a reply to message #2756] Sat, 13 May 2017 09:58 Go to previous messageGo to next message
lowen is currently offline  lowen
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snhirsch_gmail.com wrote on Fri, 12 May 2017 20:27
... Somewhere I have a software tool that can print Gerber files on a laser printer. If I had the layout next to me on the bench I could narrow the search for shorts quite a bit. Is it possible someone on the list already has a PDF of PCB front and rear?


You can grab the gerbers I used for fabrication from
Fritz's OldComputers archive


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icon3.gif  Re: Interested in a Z280 SBC [message #2762 is a reply to message #2761] Sat, 13 May 2017 13:28 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
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lowen wrote on Sat, 13 May 2017 18:58
snhirsch_gmail.com wrote on Fri, 12 May 2017 20:27
... Somewhere I have a software tool that can print Gerber files on a laser printer. If I had the layout next to me on the bench I could narrow the search for shorts quite a bit. Is it possible someone on the list already has a PDF of PCB front and rear?


You can grab the gerbers I used for fabrication from
Fritz's OldComputers archive



Embarrassed Thanks for the hint..


Adding:

Gerber - files where mystery for me ...

but now I found gerbv - A Free/Open Source Gerber Viewer and yes...it works with my Debian Linux 8 / XFCE. GREAT.

As I don't know what is the best look for printing snhirsch may please post me his printings .

index.php?t=getfile&id=426&private=0
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[Updated on: Sat, 13 May 2017 14:12]

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Re: Interested in a Z280 SBC [message #2763 is a reply to message #2762] Sat, 13 May 2017 14:39 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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Thanks for the tip on gerbv! That's very convenient. I wish it had the smarts to illuminate nets like the Cadence tool where I used to work, but you get what you pay for with free software Smile.
Re: Interested in a Z280 SBC [message #2764 is a reply to message #2763] Sat, 13 May 2017 17:22 Go to previous messageGo to next message
davetypeguy is currently offline  davetypeguy
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I usually use the free gerber viewer at EasyEDA https://gerber-viewer.easyeda.com. It lets you plot individual layers as well as combine all layers, and you can export pictured for download. It is a really nice gerber viewer.

They used to also give stats on the board, like number of vias, smallest trace size, etc, but they stopped doing that for some reason. You just upload the .zip file and it takes a best guess on layers. You can change that as well if it gets it wrong, but if it has problems, your gerber files are probably not ready for production.

[Updated on: Sat, 13 May 2017 17:24]

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Re: Interested in a Z280 SBC [message #2769 is a reply to message #2764] Sun, 14 May 2017 09:15 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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After spending about 10 hours on my board over the last day, here's where I have arrived:

Something is right on the hairy edge with regard to timing. If I apply power cold, it counts to 320k (usually, sometimes less) and hangs with the last LED on. Then, I walk away for about 10 minutes with the board powered up. When I come back, a hardware reset will get it to count past 320k (usually to 820k, but sometimes to 500-something k) and end up in the configuration dialog. From that point on the board continues to run without crashing. I can reset any number of times and have it come up (albeit with short memory count). Even a quick power-cycle will work (although more than about 10 seconds and it's back to the failed 320k count).

If I select 'Q' as the boot, it goes through all the correct motions before complaining about no hard disk and dumping me to a prompt. It remains responsive to keyboard input at this point.

With a floppy cable plugged in and my HxC SD unit (or real 1.44M 3.5 drive) on the end, it will try to access the disk but cannot read it. (This may be unrelated, since I did not have a 15pf cap and used a 10pf in the 16Mhz. tuned circuit).

Once the board is warmed up and decides to function no amount of bending, twisting, heat, cold or dropping several inches to the bench will cause it to glitch. From that evidence it's hard to see how this is a mechanical problem with the PCB or a solder bridge. I believe my earlier observation about bringing it to life by touching the board is a red-herring. It's more likely that I was accidentally moving the negative supply alligator clip far enough to hit the reset pin on the Euro connector.

Lamar, if you can send me another set of ZIP modules I will sub them in and see if that's the issue. Everything is pointing in that direction.
Re: Interested in a Z280 SBC [message #2839 is a reply to message #2769] Fri, 19 May 2017 18:22 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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The diskette subsystem is working! Swapped in the correct 15pf cap and all is well. I can access drives A and B on my HxC emulator, copy files, format, etc. The odd "warm up" behavior persists, but once it decides to work it's rock solid.
Re: Interested in a Z280 SBC [message #2840 is a reply to message #2839] Sat, 20 May 2017 01:50 Go to previous messageGo to next message
Jonas is currently offline  Jonas
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Congratulations! I would change the timing capacitor C6 for a 120pF ceramic, just in case.
Re: Interested in a Z280 SBC [message #2841 is a reply to message #2840] Sat, 20 May 2017 05:16 Go to previous messageGo to next message
snhirsch_gmail.com is currently offline  snhirsch_gmail.com
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Yes, I'm planning to do that. Lamar is sending me some replacement memory to try. Hopefully that's the cause of my flaky startup behavior and short memory count.

Am I correct in assuming that there's currently no support for booting from diskette? I currently have it setup to boot from EPROM, which doesn't automatically make A: the home drive. It times out trying to log a non-existent hard disk and I have to manually move to drive A:.
Re: Interested in a Z280 SBC [message #2843 is a reply to message #2841] Sat, 20 May 2017 05:36 Go to previous messageGo to next message
fritzeflink is currently offline  fritzeflink
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snhirsch_gmail.com wrote on Sat, 20 May 2017 14:16
Yes, I'm planning to do that. Lamar is sending me some replacement memory to try. Hopefully that's the cause of my flaky startup behavior and short memory count.

Am I correct in assuming that there's currently no support for booting from diskette? I currently have it setup to boot from EPROM, which doesn't automatically make A: the home drive. It times out trying to log a non-existent hard disk and I have to manually move to drive A:.


The support for boot device is in the setup option.

Please look into the software manual for the setup programm which is part of the bootloader.
The source code ist called setup.280 -> title 'CPU280 System Configuration Setup'

This are the menue text...

if english

h_msg: defm cr,lf,lf,'1. Disk Drives'
defm cr,lf, '2. Interfaces'
defm cr,lf, '3. Other' ### for changing boot drive ##
defm cr,lf, '0. Exit (Reboot)'
defz cr,lf, '--> '

d_msg: defm cr,lf,tab,'1. Drive A:'
defm cr,lf,tab,'2. Drive B:'
defm cr,lf,tab,'3. Drive C:'
defm cr,lf,tab,'4. Drive D:'
defm cr,lf,tab,'0. back'
defz cr,lf,tab,'--> '

s_msg: defm ')',cr,lf
defm cr,lf,tab,'1. Hardware Parameters CRT1'
defm cr,lf,tab,'2. Hardware Parameters CRT2'
defm cr,lf,tab,'3. Baud Rate CRT1'
defm cr,lf,tab,'4. Baud Rate CRT2'
defm cr,lf,tab,'5. Declarations after Reset'
defm cr,lf,tab,'0. back'
defz cr,lf,tab,'--> '

x_msg: defm cr,lf,tab,'1. Memory Size'
defm cr,lf,tab,'2. Daylight Saving'
defm cr,lf,tab,'3. Boot Drive' ## here you will change your boot drive ##
defm cr,lf,tab,'4. Drive Search Chain'
defm cr,lf,tab,'0. back'
defz cr,lf,tab,'--> '


With the setup you can change the system defaults even where your system will boot from.

.....

3. Use of the setup programm

One module of the boot loader is the setup program. It modi-
fies various settings of the CPU280. The setup program is
designed hierarchically, and currently offers three areas to be
setup:

1. Drives Declares which floppy disk drives are connected.
2. Interfaces All settings of the two serial ports on the
CPU280, plus the device assignment after reset.
3. Others Anything which didn't fit into 1. or 2.

The setup program is always used through single key
strokes; usually numeric input (one digit selects from the options
offered). Most menu items are self-explanatory, so the following
will only explain some less clear points.




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[Updated on: Sat, 20 May 2017 05:45]

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Re: Interested in a Z280 SBC [message #2844 is a reply to message #2841] Sat, 20 May 2017 05:44 Go to previous messageGo to next message
Jonas is currently offline  Jonas
Messages: 77
Registered: October 2015
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Are you using Tilmann Reh's version 1.13 or Wayne's updated and bugfixed version 1.2?
https://github.com/wwarthen/CPU280/releases

More info here:
https://github.com/wwarthen/CPU280/blob/master/SYSTEM/system .his
Re: Interested in a Z280 SBC [message #2846 is a reply to message #2844] Sat, 20 May 2017 06:47 Go to previous messageGo to previous message
fritzeflink is currently offline  fritzeflink
Messages: 80
Registered: January 2017
Location: germany
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Jonas wrote on Sat, 20 May 2017 14:44
Are you using Tilmann Reh's version 1.13 or Wayne's updated and bugfixed version 1.2?
https://github.com/wwarthen/CPU280/releases

More info here:
https://github.com/wwarthen/CPU280/blob/master/SYSTEM/system .his


Great, thanks for this link and thanks to wwarthen for his help. I added this to my http://oldcomputers.dyndns.org/public/pub/rechner/zilog/z280 /index.html


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