Z80 Rev 4.0 and DUART question

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Mitchell Smith

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Feb 13, 2022, 11:42:23 AMFeb 13
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I just started building the Z80 and DUART boards.

I'm a little confused about the DUART board.

U602 is pretty obvious but I don't understand what to do with U114 and U561.

U114 isn't on the BOM in the DUART section.

Is U114 just pin headers mounted to the underside of the DUART board?

Does anyone have a picture of a completed board?

Thanks.

Mitch
KB3GKC

Terry Gulczynski

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Feb 13, 2022, 11:53:07 AMFeb 13
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On 2/13/2022 11:42 AM, Mitchell Smith wrote:
> Is U114 just pin headers mounted to the underside of the DUART board?

Yes - these pins allow it to plugs in to the U114 socket on the CPU
board, in place of the 16C2550 DUART.


Terry

Terry Gulczynski

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Feb 13, 2022, 12:00:19 PMFeb 13
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On 2/13/2022 11:42 AM, Mitchell Smith wrote:
> U602 is pretty obvious but I don't understand what to do with U114 and U561.


U561 is the socket on top of the board (immediately beside U602) that
mounts the 16C550 used for Terminal I/O. Note the hole in the upper
left of the DUART board, as well as a matching hole on the Z80v4 CPU
board. These holes are for a standoff that holds the DUART board in
place. Make sure you use the correct set of holes for the
bottom-mounted pins to match the mainboard socket AND allow the post to
mount and hole the DUART board.

That reads a little confusing, so don't hesitate to ask for clarification.


Regards,

Terry

Terry Gulczynski

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Feb 13, 2022, 12:02:14 PMFeb 13
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On 2/13/2022 12:00 PM, Terry Gulczynski wrote:
> mount and hole

mount and HOLD

(stupid fingers. I wish they did what I WANT instead of what I DO.)

Terry

norberto...@koyado.com

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Feb 13, 2022, 1:35:49 PMFeb 13
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Mitchell Smith

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Feb 13, 2022, 4:53:41 PMFeb 13
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Thanks! That helps.
I also see that the oscillator isn't installed on the DUART board. Why is that?

Mitch

Glenn Roberts

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Feb 13, 2022, 6:10:15 PMFeb 13
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As I understand things: Normally you just pull the 1.8432 oscillator signal from the main board so you don’t need to install the local oscillator in the daughterboard.  my understanding is if you also install the 3.68 MHz oscillator on the main board and set jumper JP16 to pins 1-2 then you can run things at higher BAUD rates (but the configuration notes “caution use only with specially modified software”) so the speed demons out there will have to answer further if you’re curious. So I *think* if you’ve got the mainboard set for 3.68 Mhz this local oscillator lets you override that to slow things down for the second UART ?

 

Bottom line is you don’t need to install it on the daughterboard for “normal” operations.

 

Here is a picture of my Rev 4 board without the daughterboard installed (Note I have both UART oscillators, even though I only use the 1.8 one):

https://photos.app.goo.gl/DPVoiGiJoNEzpLEY7

 

jumper configuration document is here:

https://koyado.com/Heathkit/H8-Z80-64K-RTC-ORG0-V4_files/Z80_V_4_0_Jumper_Definition_V02.pdf

 

do you need a picture showing the male-male headers used to connect the daughterboard to the mainboard’s 40-pin socket?

 

You might want to look through some of the conversations from last year, especially spring and summer, when some of us were building out our rev 4 boards. 

https://groups.google.com/g/sebhc

 

good FAQ fodder there, though I don’t think anyone ever put one together …

 

  • Glenn

Terry Gulczynski

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Feb 13, 2022, 7:15:42 PMFeb 13
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The 1.8432MHz and 3.6864MHz oscillators are on the mainboard, with a
jumper that selects which one provides the clock for the DUART board.

The 1.8432MHz oscillator maxes out the 16C550 @ 115,200 baud, which is
more than adequate for any H19 terminal user.

The 3.6864MHz oscillator allows up to @ 230,400 baud.

You can install a third oscillator on the DUART board @ 14.7456MHz,
jumper selected on the DUART board (this jumper overrides the mainboard
osc jumper,) that allows baud rates up to 921,400 baud.

Of course, each oscillator also provides for all of the standard baud
rates BELOW the max, so each will provide the H19 connection with 9600
or 19,200 baud.

The higher baud rates are for 'other' terminals, most notably one of the
many VT-series emulators (Absolute TELNET, TeraTerm, PuTTY, and many
others.)

In addition to very high baud rates, they also bring a color terminal to
your CP/M desktop. Costly in terms of memory usage and more data
transfer to the terminal, but the higher baud rates make up for the
color control characters. I've attached a screenshot of my H8 terminal
display for an example. This is a 12MHz H8-Z80v4 with a 230,400 baud
terminal on a WinBox running an Absolute Telnet terminal emulator.

If you want to stick with the H19 terminal but really want the higher
baud rates, too, you might try Les' H19 emulator, which can run @
921,600 baud.


Regards,

Terry



On 2/13/2022 6:10 PM, Glenn Roberts wrote:
> As I understand things: Normally you just pull the 1.8432 oscillator
> signal from the main board so you don’t need to install the local
> oscillator in the daughterboard.  my understanding is if you also
> install the 3.68 MHz oscillator on the main board and set jumper JP16 to
> pins 1-2 then you can run things at higher BAUD rates (but the
> configuration notes “caution use only with specially modified software”)
> so the speed demons out there will have to answer further if you’re
> curious. So I **think** if you’ve got the mainboard set for 3.68 Mhz
> this local oscillator lets you override that to slow things down for the
> second UART ?
>
> Bottom line is you don’t need to install it on the daughterboard for
> “normal” operations.
>
> Here is a picture of my Rev 4 board without the daughterboard installed
> (Note I have both UART oscillators, even though I only use the 1.8 one):
>
> https://photos.app.goo.gl/DPVoiGiJoNEzpLEY7
> <https://photos.app.goo.gl/DPVoiGiJoNEzpLEY7>
>
> jumper configuration document is here:
>
> https://koyado.com/Heathkit/H8-Z80-64K-RTC-ORG0-V4_files/Z80_V_4_0_Jumper_Definition_V02.pdf
> <https://koyado.com/Heathkit/H8-Z80-64K-RTC-ORG0-V4_files/Z80_V_4_0_Jumper_Definition_V02.pdf>
>
> do you need a picture showing the male-male headers used to connect the
> daughterboard to the mainboard’s 40-pin socket?
>
> You might want to look through some of the conversations from last year,
> especially spring and summer, when some of us were building out our rev
> 4 boards.
>
> https://groups.google.com/g/sebhc <https://groups.google.com/g/sebhc>
>
> good FAQ fodder there, though I don’t think anyone ever put one together …
>
> * Glenn
>
> *From:* se...@googlegroups.com <se...@googlegroups.com> *On Behalf Of
> *Mitchell Smith
> *Sent:* Sunday, February 13, 2022 4:54 PM
> *To:* SEBHC <se...@googlegroups.com>
> *Subject:* Re: [sebhc] Z80 Rev 4.0 and DUART question
>
> Thanks! That helps.
>
> I also see that the oscillator isn't installed on the DUART board. Why
> is that?
>
> Mitch
>
> On Sunday, February 13, 2022 at 1:35:49 PM UTC-5 Norby wrote:
>
> <mailto:sebhc+un...@googlegroups.com>.
> <https://groups.google.com/d/msgid/sebhc/cbd01f95-1677-0c0a-4578-f0724cc2cda8%40cfl.rr.com>.
>
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Mitchell Smith

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Feb 14, 2022, 6:58:42 AMFeb 14
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Thanks Terry and Glenn!
Norberto sent me pictures so I should be good for new.
I also found some issues with the BOM which I'll try to update when I get all finished.
Unfortunately I have to go back to work on Wednesday so I may not get real far.
3 weeks on the Great Lakes then I'll be back to it.

Mitch
KB3GKC

Mitchell Smith

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Mar 19, 2022, 9:11:20 PMMar 19
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I've made some great progress on the Z80 board but I have a bunch of questions before I install it.
1. Is the 3.68 MHz oscillator required to be installed ?
2. What is the configuration of the cable between the DUART board and the main CPU board? I looked at the schematic but it's not really clear. Couldn't find the schematic for the DUART board.
3. Is the USB port on the DUART board able to handle an 8GB thumb drive? How do I access it? Is it possible to boot from it?
4. What do I do with the USB port on the VDIP1 ?
5. It appears that there's not enough room to install the Z80 board in the same slot as the 8080 CPU board. Can I install it in slot P3 on the backplane?
6. What drivers do I need to take advantage of all the features of the Z80/DUART board?
7. I want to make my own mounting brackets. What do you call the little press-in nuts used on the ends? Is there a part number or source?
IMG_20220319_173116215_HDR.jpgIMG_20220319_174517548.jpgIMG_20220319_174548677_BURST000_COVER.jpg

glenn.f...@gmail.com

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Mar 19, 2022, 9:53:56 PMMar 19
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Great progress!  Here are my answers, interspersed with your original questions…

 

From: se...@googlegroups.com <se...@googlegroups.com> On Behalf Of Mitchell Smith

Sent: Saturday, March 19, 2022 9:11 PM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] Z80 Rev 4.0 and DUART question

 

I've made some great progress on the Z80 board but I have a bunch of questions before I install it.

  1. Is the 3.68 MHz oscillator required to be installed ?

Not needed but make sure JP16 is set properly, see jumper config notes

https://koyado.com/Heathkit/H8-Z80-64K-RTC-ORG0-V4_files/Z80_V_4_0_Jumper_Definition_V02.pdf

 

  1. What is the configuration of the cable between the DUART board and the main CPU board? I looked at the schematic but it's not really clear. Couldn't find the schematic for the DUART board.

Just need a single wire.  Here’s a picture of my Rev 3.1 board but the 4.0 board is wired the same

https://photos.app.goo.gl/ty3PRpw1355HELeQ6

 

  1. Is the USB port on the DUART board able to handle an 8GB thumb drive? How do I access it? Is it possible to boot from it?

To use the USB port you must install the VDIP1.  Plug your thumb drive into the Type A usb port on the VDIP 1 (not the one on the daughterboard itself).  Yes 8G is fine.  See answer to Q4 below for how to access.  It should handle a wide range of thumb drives but is limited to 12-, 16- or 32-bit FAT configurations.  If you configure  your EEPROM with firmware from Douglas Miller he does include an ability to boot programs from the USB. We currently don’t have a way to bootstrap a full OS from USB (to my knowledge). For instructions on Douglas’ firmware see http://durgadas.com/sebhc/mms89/h8mon2/H8-Monitor-2.pdf

 

  1. What do I do with the USB port on the VDIP1 ?

This is where you plug in your thumb drive.  The primary software that we have written is for accessing thumb drives to copy files to/from.  It is also possible to talk to other devices (e.g. printers) but our work there has been less fruitful. I recently wrote a REMarks issue that covers all  of this

REMarks Issue 6 - 14 February 2022.pdf (sebhc.github.io)  I highly recommend getting a desktop USB extension cable which you can plug into the VDIP1 and then have the main insertion point sit on your desktop, e.g. https://www.startech.com/en-us/cables/usbextaa5dsk

 

  1. It appears that there's not enough room to install the Z80 board in the same slot as the 8080 CPU board. Can I install it in slot P3 on the backplane?

Yes.  You may have to extend the cable that attaches to the front panel (Heath was a bit short-sighted in specifying the lengths of some of those wires!)

 

  1. What drivers do I need to take advantage of all the features of the Z80/DUART board?

The Heath OSes should work fine with the board. Consider going to CP/M3 or MP/M, both of which Douglas has posted information on.  CP/M3 can use the 512K RAM board (if you plan to build that).

https://koyado.com/Heathkit/H8-512KB_RAM_MMU.html

 

  1. I want to make my own mounting brackets. What do you call the little press-in nuts used on the ends? Is there a part number or source?

Those are 6-32 “self clinching” nuts.  I found 100 on Amazon for $9.99

 

 

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image003.jpg

Kenneth L. Owen tx836519

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Mar 19, 2022, 10:49:56 PMMar 19
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Hi Mitchell,

 

See if this helps.

 

  • ken

 

Sent from Mail for Windows

 

From: Mitchell Smith
Sent: Saturday, March 19, 2022 9:11 PM
To: SEBHC

Subject: Re: [sebhc] Z80 Rev 4.0 and DUART question

 

I've made some great progress on the Z80 board but I have a bunch of questions before I install it.

1. Is the 3.68 MHz oscillator required to be installed ?

2. What is the configuration of the cable between the DUART board and the main CPU board? I looked at the schematic but it's not really clear. Couldn't find the schematic for the DUART board.

3. Is the USB port on the DUART board able to handle an 8GB thumb drive? How do I access it? Is it possible to boot from it?

4. What do I do with the USB port on the VDIP1 ?

5. It appears that there's not enough room to install the Z80 board in the same slot as the 8080 CPU board. Can I install it in slot P3 on the backplane?

6. What drivers do I need to take advantage of all the features of the Z80/DUART board?

7. I want to make my own mounting brackets. What do you call the little press-in nuts used on the ends? Is there a part number or source?

To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+un...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/538f7b05-58ec-4d59-a44b-048e7492de5an%40googlegroups.com.

 

H8-Z80-DUART, v3.1.searchable.pdf
IMG_20220319_173116215_HDR.jpg
IMG_20220319_174548677_BURST000_COVER.jpg
IMG_20220319_174517548.jpg

Kenneth L. Owen tx836519

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Mar 19, 2022, 11:08:57 PMMar 19
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Hi Mitchell,

 

This is the drawing that I gave to the metal shop to make the heat sink mounting bracket.

 

  • ken

 

Sent from Mail for Windows

 

From: Mitchell Smith
Sent: Saturday, March 19, 2022 9:11 PM
To: SEBHC

Subject: Re: [sebhc] Z80 Rev 4.0 and DUART question

 

I've made some great progress on the Z80 board but I have a bunch of questions before I install it.

1. Is the 3.68 MHz oscillator required to be installed ?

2. What is the configuration of the cable between the DUART board and the main CPU board? I looked at the schematic but it's not really clear. Couldn't find the schematic for the DUART board.

3. Is the USB port on the DUART board able to handle an 8GB thumb drive? How do I access it? Is it possible to boot from it?

4. What do I do with the USB port on the VDIP1 ?

5. It appears that there's not enough room to install the Z80 board in the same slot as the 8080 CPU board. Can I install it in slot P3 on the backplane?

6. What drivers do I need to take advantage of all the features of the Z80/DUART board?

7. I want to make my own mounting brackets. What do you call the little press-in nuts used on the ends? Is there a part number or source?

To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+un...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/538f7b05-58ec-4d59-a44b-048e7492de5an%40googlegroups.com.

 

H8-HeatSink.PDF
IMG_20220319_173116215_HDR.jpg
IMG_20220319_174548677_BURST000_COVER.jpg
IMG_20220319_174517548.jpg

George Farris

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Mar 20, 2022, 12:01:37 AMMar 20
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Nice schematic Ken, very Heathkity ish.  What did you use to draw it?

George

Mitchell Smith

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Mar 20, 2022, 7:33:33 AMMar 20
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Outstanding! Thank you very much. Going to install it right now.

Mitch
kb3gkc

Mitchell Smith

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Mar 20, 2022, 9:40:01 AMMar 20
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Here's where I'm at...
My system has only the Z80 board and the H17 controller board.

When I power on the system, the front panel shows:
PWR = On
RUN = On
MON = Off
ION = Dimly lit
All 7-seg LEDs are off

Hitting 0/reset turn off RUN and ION momentarily

On the CPU board, the power led is on
Halt led is off
VDIP Leds blink when I turn on the power.
I've verified that I have 5 volts on a few chips. So I think power is getting to the board. Still need to verify the 12 volt supply.
Pretty sure I have all the jumpers set correctly.
There are jumpers on the DUART board but I don't know how to set them. I pulled the DUART board off but got the same front panel behavior.

When I burned the ROM I used the h8mon2-v2.0b24.rom file. I set the DIP switches according to Douglas Miller's config on page 8.
So I have
Switch
0 1 2 3 4 5 6 7
0 0 1 1 0 1 0 0

So that's H17 only. Nothing on port 170Q. Default Boot from 174Q. 9600 baud console port.

One jumper that I don't quite understand is JP11. Right (2 3): PAM37 can disable ROM (default)
I may be confused but I thought the PAM37 was the ROM on the 8080 CPU board. So this doesn't make sense to me.

Wishing I had one of those bus extender boards for troubleshooting....

Douglas Miller

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Mar 20, 2022, 10:46:36 AMMar 20
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In the case of JP11, the text "PAM37" should be read as just "software". I thought "PAM37" was created for the Z80 boards and "XCON8" was for the 8080, but it may be more subtle than that.

The "b24" ROM is not the absolute latest (hazards of posting a static copy), but can't think of any problems running that. The latest is http://sebhc.durgadas.com/mms89/h8mon2/h8mon2-v2.0b28.rom, but at this point don't have a compelling reason for you to update.

With ION "dim" and 7-seg display off, I wonder if the connections/jumpers between the CPU and front panel boards are correct/complete. Or else maybe something related to 2mS interrupts (I'm not sure if there is a way to jumper the board such that both 2mS are running - the ROM only enables one).

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glenn.f...@gmail.com

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Mar 20, 2022, 11:54:40 AMMar 20
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Mitch: I attempted to reproduce your setup and had *success* booting HDOS 2.0 from floppy, so here is a datapoint for you to compare to.  I used the “les bird” H17 board and this is with the new front panel and backplane but  otherwise should be same as you.

 

Just a reminder in case you missed it – the switch logic on SW501 is inverted so closed =’0’, open = ‘1’

 

Here is a google album with shots including a picture of my board and the jumpers.  Please check yours versus this setup

https://photos.app.goo.gl/WCVQVTqK5Z4SSUj46

 

the other thing that occurred to me is that you’ve only ever used your H17 controller board with the 8080 CPU, right?  In the Heath Z80 manual there are a few mod’s to the H17 controller board spelled out for use with the Z80.  Not sure if that could be partially the cause?...

 

https://sebhc.github.io/sebhc/documentation/hardware/H8/H8-6_Op_Sc.zip

 

 

 

 

From: se...@googlegroups.com <se...@googlegroups.com> On Behalf Of Mitchell Smith

Sent: Sunday, March 20, 2022 9:40 AM
To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] Z80 Rev 4.0 and DUART question

 

Here's where I'm at...

On Monday, February 14, 2022 at 6:58:42 AM UTC-5 Mitchell Smith wrote:

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Mitchell Smith

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Mar 20, 2022, 5:08:06 PMMar 20
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So far I have found a bad IC at U12. The 74LS32 was getting so hot I couldn't touch it.
Installed a new one but that didn't fix the problem.
Now my PWR and RUN leds are the only ones that come on.
The ION is now off.
I have powered up the board on my bench outside of the computer.
Should the led on the DUART board (D1) be lit?

glenn.f...@gmail.com

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Mar 20, 2022, 7:01:59 PMMar 20
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Mitch: I reviewed your jumper settings from your picture and spotted a few things to mention, I don’t think any of these explain the issue though:

 

JP9 should be INSERTED unless using an external H8-4 board.  When it’s removed it disables the UART/USB daughterboard.

 

You have a jumper sitting on one pin for the “P7” connector as if to potentially jumper those pins some day.  That’s not a jumper but a connector that can be used to connect to the front panel.  This is one of the solutions for keeping the front panel running at 2.048 Mhz when the CPU is running at higher speeds (another solution is to modify the front panel per instructions I posted previously - https://photos.app.goo.gl/Pqv585iafF2jFsCF7.  This is not a killer issue and doesn’t explain your current problem, but you may want to look into this once you get your CPU board working.  It will let you still use the LEDs and front panel functions even at higher CPU speeds. The newer rev front panel boards already have this modification).

 

It looks like you have JP2 installed on the CHARGE jumper.  This would be for a rechargeable coin cell. I think our consensus has been to use a regular CR2032 (non rechargeable) Li-Ion cell here and leave JP2 NOT inserted.  This has worked fine for me…

 

Also I’ll beat Norberto to the punch and recommend you glue a closed shorting block into the gap between the two Samtec edge connectors.  It’s just too easy to install these boards “one off” and fry your power supply.

 

On the UART/USB daughterboard:  schematic is here (this board was originally part of the 3.1 CPU design, hence that’s where it is documented):

https://koyado.com/Heathkit/H8-Z80-64K-RTC-ORG0-V3_files/Z80_DUARTs_USB_Schematics.pdf

 

LED D1 should normally not be lit as it indicates I/O activity on USB port 1 (the port on the daughterboard).  I use Port 2 (the one on the VDIP1 itself) for all thumb drive operation.  D1 will light momentarily when the system is reset.

 

You should insert JP1 on the daughter board to pull the 1.8432 Mhz signal from the CPU board (you need not assemble the local clock circuitry).

 

keep us posted as you progress!

Mitchell Smith

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Mar 20, 2022, 8:44:46 PMMar 20
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Thanks Glenn. I'll work on this more tomorrow.

Mitchell Smith

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Mar 23, 2022, 4:14:08 PMMar 23
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spent some time testing today.
I pulled all the IC chips and tested them using my XGecu Pro EEPROM programmer.
Found another bad 74LS32 and a possibly intermittent 74LS10.

Unfortunately, I had no spares so I have to wait on Jameco to send replacements.

Glenn Roberts

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Mar 23, 2022, 4:27:29 PMMar 23
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Sorry you’re having a rough go of it!  it makes you wonder if the bad ‘32s are a symptom or a cause?  If a symptom then the problem is deeper. If a cause, then perhaps bad chips. I had my first experience with bogus chips recently. A 74LS123 that had TI markings but looked suspiciously fake.  Sure enough it didn’t work.  unfortunately I’m not sure where I got it so I was unable to follow up with the supplier, but it was from one of the major parts companies.

 

I recently placed an order with Jameco and got an extremely fast result. 2 days I think (and this was USPS shipping!). so let’s hope…

 

I also did Mouser and got good response (3 days I think) and Phoenix Enterprises (https://www.peconnectors.com/).  I like Phoenis for connectors but hate their shipping policy.  If you have more than 15 lines on your order you have to split it in two; they only ship UPS and it’s a little pricey ($13), and there’s a $30 minimum per order.  And it took the longest – over a week!

George Farris

unread,
Mar 23, 2022, 4:38:01 PMMar 23
to se...@googlegroups.com
I just ordered a bunch of IC's from Unicorn Electronics, has anyone here had a poor experience with them?

George

Mitchell Smith

unread,
Mar 23, 2022, 5:07:03 PMMar 23
to SEBHC
Glenn,
This isn't the first time I received bad chips from Jameco. Last time it was an EEPROM. They replaced it of course.

Pretty sure the 74LS32s were either part of a bad batch or they are fake. I don't recognize the mfg symbol on the chips but it looks a lot like an incomplete TI logo.

So I have either bad luck or brown thumb.
Nothing I do ever goes easy it seems.

Lessons learned so far...
1. Always order extra ICs.
2. Test the ICs before installing them

Hopefully the new chips will resolve my problems.

Thanks for the advice as usual.

Mitch
kb3gkc

Mike Loewen

unread,
Mar 23, 2022, 5:14:27 PMMar 23
to 'George Farris' via SEBHC

I've ordered many times from Unicorn, and always had good service.

On Wed, 23 Mar 2022, 'George Farris' via SEBHC wrote:

> I just ordered a bunch of IC's from Unicorn Electronics, has anyone
> here had a poor experience with them?
>
> George
>
>
> On Wed, 2022-03-23 at 16:27 -0400, Glenn Roberts wrote:
>> Sorry you?re having a rough go of it!  it makes you wonder if the bad
>> ?32s are a symptom or a cause?  If a symptom then the problem is
>> deeper. If a cause, then perhaps bad chips. I had my first experience
>> with bogus chips recently. A 74LS123 that had TI markings but looked
>> suspiciously fake.  Sure enough it didn?t work.  unfortunately I?m
>> not sure where I got it so I was unable to follow up with the
>> supplier, but it was from one of the major parts companies.
>>  
>> I recently placed an order with Jameco and got an extremely fast
>> result. 2 days I think (and this was USPS shipping!). so let?s hope?
>>  
>> I also did Mouser and got good response (3 days I think) and Phoenix
>> Enterprises (https://www.peconnectors.com/).  I like Phoenis for
>> connectors but hate their shipping policy.  If you have more than 15
>> lines on your order you have to split it in two; they only ship UPS
>> and it?s a little pricey ($13), and there?s a $30 minimum per order. 
>> And it took the longest ? over a week!
>>  
>>  
>>  
>> From: se...@googlegroups.com <se...@googlegroups.com> On Behalf Of
>> Mitchell Smith
>> Sent: Wednesday, March 23, 2022 4:14 PM
>> To: SEBHC <se...@googlegroups.com>
>> Subject: Re: [sebhc] Z80 Rev 4.0 and DUART question
>>  
>> spent some time testing today.
>> I pulled all the IC chips and tested them using my XGecu Pro EEPROM
>> programmer.
>> Found another bad 74LS32 and a possibly intermittent 74LS10.
>>  
>> Unfortunately, I had no spares so I have to wait on Jameco to send
>> replacements.
>>  
>>  
>>  
>> On Sunday, March 20, 2022 at 8:44:46 PM UTC-4 Mitchell Smith wrote:
>>> Thanks Glenn. I'll work on this more tomorrow.
>>>  
>>>  
>>> On Sunday, March 20, 2022 at 7:01:59 PM UTC-4 Glenn wrote:
>>>> Mitch: I reviewed your jumper settings from your picture and
>>>> spotted a few things to mention, I don?t think any of these
>>>> explain the issue though:
>>>>  
>>>> JP9 should be INSERTED unless using an external H8-4 board.  When
>>>> it?s removed it disables the UART/USB daughterboard.
>>>>  
>>>> You have a jumper sitting on one pin for the ?P7? connector as if
>>>> to potentially jumper those pins some day.  That?s not a jumper
>>>> but a connector that can be used to connect to the front panel. 
>>>> This is one of the solutions for keeping the front panel running
>>>> at 2.048 Mhz when the CPU is running at higher speeds (another
>>>> solution is to modify the front panel per instructions I posted
>>>> previously - https://photos.app.goo.gl/Pqv585iafF2jFsCF7.  This
>>>> is not a killer issue and doesn?t explain your current problem,
>>>> but you may want to look into this once you get your CPU board
>>>> working.  It will let you still use the LEDs and front panel
>>>> functions even at higher CPU speeds. The newer rev front panel
>>>> boards already have this modification).
>>>>  
>>>> It looks like you have JP2 installed on the CHARGE jumper.  This
>>>> would be for a rechargeable coin cell. I think our consensus has
>>>> been to use a regular CR2032 (non rechargeable) Li-Ion cell here
>>>> and leave JP2 NOT inserted.  This has worked fine for me?
>>>>  
>>>> Also I?ll beat Norberto to the punch and recommend you glue a
>>>> closed shorting block into the gap between the two Samtec edge
>>>> connectors.  It?s just too easy to install these boards ?one off?
>>>> and fry your power supply.
>>>>  
>>>> On the UART/USB daughterboard:  schematic is here (this board was
>>>> originally part of the 3.1 CPU design, hence that?s where it is
>>>>> compare to.  I used the ?les bird? H17 board and this is with
>>>>> the new front panel and backplane but  otherwise should be same
>>>>> as you.
>>>>>  
>>>>> Just a reminder in case you missed it ? the switch logic on
>>>>> SW501 is inverted so closed =?0?, open = ?1?
>>>>>  
>>>>> Here is a google album with shots including a picture of my
>>>>> board and the jumpers.  Please check yours versus this setup
>>>>> https://photos.app.goo.gl/WCVQVTqK5Z4SSUj46
>>>>>  
>>>>> the other thing that occurred to me is that you?ve only ever
>>>>> used your H17 controller board with the 8080 CPU, right?  In
>>>>> the Heath Z80 manual there are a few mod?s to the H17
>>>>>>>> * ken
>>>>>>>>>>> signal from the main board so you don?t need to
>>>>>>>>>> install the local
>>>>>>>>>>> oscillator in the daughterboard.  my understanding
>>>>>>>>>> is if you also
>>>>>>>>>>> install the 3.68 MHz oscillator on the main board
>>>>>>>>>> and set jumper JP16 to
>>>>>>>>>>> pins 1-2 then you can run things at higher BAUD
>>>>>>>>>> rates (but the
>>>>>>>>>>> configuration notes ?caution use only with
>>>>>>>>>> specially modified software?)
>>>>>>>>>>> so the speed demons out there will have to answer
>>>>>>>>>> further if you?re
>>>>>>>>>>> curious. So I **think** if you?ve got the mainboard
>>>>>>>>>> set for 3.68 Mhz
>>>>>>>>>>> this local oscillator lets you override that to
>>>>>>>>>> slow things down for the
>>>>>>>>>>> second UART ?
>>>>>>>>>>>
>>>>>>>>>>> Bottom line is you don?t need to install it on the
>>>>>>>>>> daughterboard for
>>>>>>>>>>> ?normal? operations.
>>>>>>>>>>>
>>>>>>>>>>> Here is a picture of my Rev 4 board without the
>>>>>>>>>> daughterboard installed
>>>>>>>>>>> (Note I have both UART oscillators, even though I
>>>>>>>>>> only use the 1.8 one):
>>>>>>>>>>>
>>>>>>>>>>> https://photos.app.goo.gl/DPVoiGiJoNEzpLEY7
>>>>>>>>>>> <https://photos.app.goo.gl/DPVoiGiJoNEzpLEY7>
>>>>>>>>>>>
>>>>>>>>>>> jumper configuration document is here:
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>> https://koyado.com/Heathkit/H8-Z80-64K-RTC-ORG0-V4_files/Z80_V_4_0_Jumper_Definition_V02.pdf
>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>> <https://koyado.com/Heathkit/H8-Z80-64K-RTC-ORG0-V4_files/Z80_V_4_0_Jumper_Definition_V02.pdf
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> do you need a picture showing the male-male headers
>>>>>>>>>> used to connect the
>>>>>>>>>>> daughterboard to the mainboard?s 40-pin socket?
>>>>>>>>>>>
>>>>>>>>>>> You might want to look through some of the
>>>>>>>>>> conversations from last year,
>>>>>>>>>>> especially spring and summer, when some of us were
>>>>>>>>>> building out our rev
>>>>>>>>>>> 4 boards.
>>>>>>>>>>>
>>>>>>>>>>> https://groups.google.com/g/sebhc
>>>>>>>>>> <https://groups.google.com/g/sebhc>
>>>>>>>>>>>
>>>>>>>>>>> good FAQ fodder there, though I don?t think anyone
>>>>>>>>>> ever put one together ?
>>>> https://groups.google.com/d/msgid/sebhc/fa8293f1-12a0-483f-89b4-36772b268fe7n%40googlegroups.com
>>>> .
>
> --
> You received this message because you are subscribed to the Google Groups "SEBHC" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to sebhc+un...@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/5aa11b20c6c27508adcc2439721f779ccb9a3c2b.camel%40gmsys.com.
>

Mike Loewen mlo...@cpumagic.scol.pa.us
Old Technology http://q7.neurotica.com/Oldtech/

Glenn Roberts

unread,
Mar 23, 2022, 5:17:05 PMMar 23
to se...@googlegroups.com

Yeah, well Jameco’s favorite manufacturer is “Major Brands” 😊

 

For ICs it might be preferable to use DigiKey or Mouser.

Mike Loewen

unread,
Mar 23, 2022, 5:29:59 PMMar 23
to se...@googlegroups.com

Also try Anchor Electronics in Santa Clara. Their prices are quite low, and
they stock a lot of older ICs. Check their price list:

https://anchor-electronics.com/

On Wed, 23 Mar 2022, Glenn Roberts wrote:

> Yeah, well Jameco?s favorite manufacturer is ?Major Brands? ?
>
>
>
> For ICs it might be preferable to use DigiKey or Mouser.
>
>
>
> From: se...@googlegroups.com <se...@googlegroups.com> On Behalf Of Mitchell Smith
> Sent: Wednesday, March 23, 2022 5:07 PM
> To: SEBHC <se...@googlegroups.com>
> Subject: Re: [sebhc] Z80 Rev 4.0 and DUART question
>
>
>
> Glenn,
>
> This isn't the first time I received bad chips from Jameco. Last time it was an EEPROM. They replaced it of course.
>
>
>
> Pretty sure the 74LS32s were either part of a bad batch or they are fake. I don't recognize the mfg symbol on the chips but it looks a lot like an incomplete TI logo.
>
>
>
> So I have either bad luck or brown thumb.
>
> Nothing I do ever goes easy it seems.
>
>
>
> Lessons learned so far...
>
> 1. Always order extra ICs.
>
> 2. Test the ICs before installing them
>
>
>
> Hopefully the new chips will resolve my problems.
>
>
>
> Thanks for the advice as usual.
>
>
>
> Mitch
>
> kb3gkc
>
>
>
>
>
>
>
>
>
> On Wednesday, March 23, 2022 at 4:38:01 PM UTC-4 frg wrote:
>
> I just ordered a bunch of IC's from Unicorn Electronics, has anyone here had a poor experience with them?
>
>
>
> George
>
>
>
>
>
> On Wed, 2022-03-23 at 16:27 -0400, Glenn Roberts wrote:
>
> Sorry you?re having a rough go of it! it makes you wonder if the bad ?32s are a symptom or a cause? If a symptom then the problem is deeper. If a cause, then perhaps bad chips. I had my first experience with bogus chips recently. A 74LS123 that had TI markings but looked suspiciously fake. Sure enough it didn?t work. unfortunately I?m not sure where I got it so I was unable to follow up with the supplier, but it was from one of the major parts companies.
>
>
>
> I recently placed an order with Jameco and got an extremely fast result. 2 days I think (and this was USPS shipping!). so let?s hope?
>
>
>
> I also did Mouser and got good response (3 days I think) and Phoenix Enterprises (https://www.peconnectors.com/). I like Phoenis for connectors but hate their shipping policy. If you have more than 15 lines on your order you have to split it in two; they only ship UPS and it?s a little pricey ($13), and there?s a $30 minimum per order. And it took the longest ? over a week!
>
>
>
>
>
>
>
> From: se...@googlegroups.com <mailto:se...@googlegroups.com> <se...@googlegroups.com <mailto:se...@googlegroups.com> > On Behalf Of Mitchell Smith
> Sent: Wednesday, March 23, 2022 4:14 PM
> To: SEBHC <se...@googlegroups.com <mailto:se...@googlegroups.com> >
> Subject: Re: [sebhc] Z80 Rev 4.0 and DUART question
>
>
>
> spent some time testing today.
>
> I pulled all the IC chips and tested them using my XGecu Pro EEPROM programmer.
>
> Found another bad 74LS32 and a possibly intermittent 74LS10.
>
>
>
> Unfortunately, I had no spares so I have to wait on Jameco to send replacements.
>
>
>
>
>
>
>
> On Sunday, March 20, 2022 at 8:44:46 PM UTC-4 Mitchell Smith wrote:
>
> Thanks Glenn. I'll work on this more tomorrow.
>
>
>
>
>
> On Sunday, March 20, 2022 at 7:01:59 PM UTC-4 Glenn wrote:
>
> Mitch: I reviewed your jumper settings from your picture and spotted a few things to mention, I don?t think any of these explain the issue though:
>
>
>
> JP9 should be INSERTED unless using an external H8-4 board. When it?s removed it disables the UART/USB daughterboard.
>
>
>
> You have a jumper sitting on one pin for the ?P7? connector as if to potentially jumper those pins some day. That?s not a jumper but a connector that can be used to connect to the front panel. This is one of the solutions for keeping the front panel running at 2.048 Mhz when the CPU is running at higher speeds (another solution is to modify the front panel per instructions I posted previously - https://photos.app.goo.gl/Pqv585iafF2jFsCF7. This is not a killer issue and doesn?t explain your current problem, but you may want to look into this once you get your CPU board working. It will let you still use the LEDs and front panel functions even at higher CPU speeds. The newer rev front panel boards already have this modification).
>
>
>
> It looks like you have JP2 installed on the CHARGE jumper. This would be for a rechargeable coin cell. I think our consensus has been to use a regular CR2032 (non rechargeable) Li-Ion cell here and leave JP2 NOT inserted. This has worked fine for me?
>
>
>
> Also I?ll beat Norberto to the punch and recommend you glue a closed shorting block into the gap between the two Samtec edge connectors. It?s just too easy to install these boards ?one off? and fry your power supply.
>
>
>
> On the UART/USB daughterboard: schematic is here (this board was originally part of the 3.1 CPU design, hence that?s where it is documented):
>
> https://koyado.com/Heathkit/H8-Z80-64K-RTC-ORG0-V3_files/Z80_DUARTs_USB_Schematics.pdf
>
>
>
> LED D1 should normally not be lit as it indicates I/O activity on USB port 1 (the port on the daughterboard). I use Port 2 (the one on the VDIP1 itself) for all thumb drive operation. D1 will light momentarily when the system is reset.
>
>
>
> You should insert JP1 on the daughter board to pull the 1.8432 Mhz signal from the CPU board (you need not assemble the local clock circuitry).
>
>
>
> keep us posted as you progress!
>
>
>
>
>
> From: se...@googlegroups.com <mailto:se...@googlegroups.com> <se...@googlegroups.com <mailto:se...@googlegroups.com> > On Behalf Of Mitchell Smith
> Sent: Sunday, March 20, 2022 5:08 PM
> To: SEBHC <se...@googlegroups.com <mailto:se...@googlegroups.com> >
> Subject: Re: [sebhc] Z80 Rev 4.0 and DUART question
>
>
>
> So far I have found a bad IC at U12. The 74LS32 was getting so hot I couldn't touch it.
>
> Installed a new one but that didn't fix the problem.
>
> Now my PWR and RUN leds are the only ones that come on.
>
> The ION is now off.
>
> I have powered up the board on my bench outside of the computer.
>
> Should the led on the DUART board (D1) be lit?
>
>
>
> On Sunday, March 20, 2022 at 11:54:40 AM UTC-4 Glenn wrote:
>
> Mitch: I attempted to reproduce your setup and had *success* booting HDOS 2.0 from floppy, so here is a datapoint for you to compare to. I used the ?les bird? H17 board and this is with the new front panel and backplane but otherwise should be same as you.
>
>
>
> Just a reminder in case you missed it ? the switch logic on SW501 is inverted so closed =?0?, open = ?1?
>
>
>
> Here is a google album with shots including a picture of my board and the jumpers. Please check yours versus this setup
>
> https://photos.app.goo.gl/WCVQVTqK5Z4SSUj46
>
>
>
> the other thing that occurred to me is that you?ve only ever used your H17 controller board with the 8080 CPU, right? In the Heath Z80 manual there are a few mod?s to the H17 controller board spelled out for use with the Z80. Not sure if that could be partially the cause?...
>
>
>
> https://sebhc.github.io/sebhc/documentation/hardware/H8/H8-6_Op_Sc.zip
>
>
>
>
>
>
>
>
>
> From: se...@googlegroups.com <mailto:se...@googlegroups.com> <se...@googlegroups.com <mailto:se...@googlegroups.com> > On Behalf Of Mitchell Smith
>
> Sent: Sunday, March 20, 2022 9:40 AM
> To: SEBHC <se...@googlegroups.com <mailto:se...@googlegroups.com> >
> Subject: Re: [sebhc] Z80 Rev 4.0 and DUART question
>
>
>
> * ken
>
>
>
> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for Windows
>> signal from the main board so you don?t need to install the local
>> oscillator in the daughterboard. my understanding is if you also
>> install the 3.68 MHz oscillator on the main board and set jumper JP16 to
>> pins 1-2 then you can run things at higher BAUD rates (but the
>> configuration notes ?caution use only with specially modified software?)
>> so the speed demons out there will have to answer further if you?re
>> curious. So I **think** if you?ve got the mainboard set for 3.68 Mhz
>> this local oscillator lets you override that to slow things down for the
>> second UART ?
>>
>> Bottom line is you don?t need to install it on the daughterboard for
>> ?normal? operations.
>>
>> Here is a picture of my Rev 4 board without the daughterboard installed
>> (Note I have both UART oscillators, even though I only use the 1.8 one):
>>
>> https://photos.app.goo.gl/DPVoiGiJoNEzpLEY7
>> <https://photos.app.goo.gl/DPVoiGiJoNEzpLEY7>
>>
>> jumper configuration document is here:
>>
>> https://koyado.com/Heathkit/H8-Z80-64K-RTC-ORG0-V4_files/Z80_V_4_0_Jumper_Definition_V02.pdf
>> <https://koyado.com/Heathkit/H8-Z80-64K-RTC-ORG0-V4_files/Z80_V_4_0_Jumper_Definition_V02.pdf>
>>
>> do you need a picture showing the male-male headers used to connect the
>> daughterboard to the mainboard?s 40-pin socket?
>>
>> You might want to look through some of the conversations from last year,
>> especially spring and summer, when some of us were building out our rev
>> 4 boards.
>>
>> https://groups.google.com/g/sebhc <https://groups.google.com/g/sebhc>
>>
>> good FAQ fodder there, though I don?t think anyone ever put one together ?
>>
>> * Glenn
>>
>> *From:* se...@googlegroups.com <mailto:se...@googlegroups.com> <se...@googlegroups.com <mailto:se...@googlegroups.com> > *On Behalf Of
>> *Mitchell Smith
>> *Sent:* Sunday, February 13, 2022 4:54 PM
>> *To:* SEBHC <se...@googlegroups.com <mailto:se...@googlegroups.com> >
>> <https://groups.google.com/d/msgid/sebhc/2e526b7d-3ba5-4b58-8fa6-b5cb316b6613n%40googlegroups.com?utm_medium=email <https://groups.google.com/d/msgid/sebhc/2e526b7d-3ba5-4b58-8fa6-b5cb316b6613n%40googlegroups.com?utm_medium=email&utm_source=footer> &utm_source=footer>.
>>
>> --
>> You received this message because you are subscribed to the Google
>> Groups "SEBHC" group.
>> To unsubscribe from this group and stop receiving emails from it, send
>> an email to sebhc+un...@googlegroups.com <mailto:sebhc+un...@googlegroups.com>
>> <https://groups.google.com/d/msgid/sebhc/00a201d8212e%24dae45940%2490ad0bc0%24%40gmail.com?utm_medium=email <https://groups.google.com/d/msgid/sebhc/00a201d8212e%24dae45940%2490ad0bc0%24%40gmail.com?utm_medium=email&utm_source=footer> &utm_source=footer>.
>
> --
> You received this message because you are subscribed to the Google Groups "SEBHC" group.
>
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>
> --
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>
> To view this discussion on the web visit https://groups.google.com/d/msgid/sebhc/fa8293f1-12a0-483f-89b4-36772b268fe7n%40googlegroups.com <https://groups.google.com/d/msgid/sebhc/fa8293f1-12a0-483f-89b4-36772b268fe7n%40googlegroups.com?utm_medium=email&utm_source=footer> .
>
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Steven Hirsch

unread,
Mar 23, 2022, 6:13:40 PMMar 23
to 'George Farris' via SEBHC
On Wed, 23 Mar 2022, 'George Farris' via SEBHC wrote:

> I just ordered a bunch of IC's from Unicorn Electronics, has anyone here had a poor experience with them?

I've bought over 100 ICs from them over the years and have never had a
problem. You don't know what brand you're going to receive necessarily,
but everything has worked.
> # ken
> https://groups.google.com/d/msgid/sebhc/5aa11b20c6c27508adcc2439721f779ccb9a3c2b.camel%40gmsys.com.
>
>

--

Steven Hirsch

unread,
Mar 23, 2022, 6:29:29 PMMar 23
to se...@googlegroups.com
On 3/23/22 17:17, Glenn Roberts wrote:

> Yeah, well Jameco’s favorite manufacturer is “Major Brands” 😊
>
> For ICs it might be preferable to use DigiKey or Mouser.
>

Yes, if you want traceable parts from a specific manufacturer then DigiKey and
Mouser are the right places to go. That said, I've never had a problem with
Jameco or Unicorn.


Mitchell Smith

unread,
Mar 29, 2022, 2:47:54 PMMar 29
to SEBHC
Really thought I nailed the problem with the bad 74LS32 on my board.
Well of course it didn't solve the problem.
I have the same symptoms as before. All 7-seg leds are off. RUN and MON are on. INT is off.
Although when I first powered up, the INT light came on and stayed on until I did a reset. Then it went out and stayed out.
I programmed a new EEPROM with the latest h8mon2-v2.0b28.rom just because.
I am testing this with no other boards in the system.
I've tested all the 74xx series chips with my EEPROM programmer.

So at this point, I need some troubleshooting guidance to narrow down the problem.
I won't have much more time to work on this since I'm heading out tomorrow for work. But I want to really study the schematic and understand it better.
What signals should I begin looking at?

norberto.collado koyado.com

unread,
Mar 29, 2022, 2:50:54 PMMar 29
to se...@googlegroups.com
Please take high resolution pictures of side 1 and side 2 of the board to see if any issues.

Thanks,
Norberto

From: se...@googlegroups.com <se...@googlegroups.com> on behalf of Mitchell Smith <kb3...@gmail.com>
Sent: Tuesday, March 29, 2022 11:47 AM

To: SEBHC <se...@googlegroups.com>
Subject: Re: [sebhc] Z80 Rev 4.0 and DUART question
--
You received this message because you are subscribed to the Google Groups "SEBHC" group.
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Mitchell Smith

unread,
Mar 29, 2022, 3:42:35 PMMar 29
to SEBHC
Some pictures

I've been over my solder connections multiple times.
Verified the jumpers and switches at least 4 times.


Mitchell Smith

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Mar 29, 2022, 3:49:50 PMMar 29
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Made an error with my symptoms. All 7-seg leds are off. RUN and PWR are on. INT is off.

Norby

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Mar 29, 2022, 7:45:29 PMMar 29
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Please take out jumper JP201. I’m still reviewing the pictures.

Sent from my iPhone

On Mar 29, 2022, at 12:49 PM, Mitchell Smith <kb3...@gmail.com> wrote:

Made an error with my symptoms. All 7-seg leds are off. RUN and PWR are on. INT is off.
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norberto...@koyado.com

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Mar 29, 2022, 9:15:47 PMMar 29
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I cannot see anything wrong with your board. Can you ship the board back to me with the DUART to debug it further?

 

Shipped to:

NORBERTO COLLADO
PO BOX 988
HILLSBORO OR 97123-0988

 

Thanks,

Norberto

 

From: se...@googlegroups.com <se...@googlegroups.com> On Behalf Of Norby
Sent: Tuesday, March 29, 2022 4:45 PM
To: se...@googlegroups.com
Subject: Re: [sebhc] Z80 Rev 4.0 and DUART question

 

Please take out jumper JP201. I’m still reviewing the pictures.

Mitchell Smith

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Mar 30, 2022, 11:46:31 AMMar 30
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Norberto,
There is no jumper on JP201. Those are open pins.

Norby

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Mar 30, 2022, 1:08:39 PMMar 30
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Thanks! If you cannot make any progress just send it to me. I will start checking the interrupt circuit. Posible bend pins. The board schematics are in the website.

Sent from my iPhone

On Mar 30, 2022, at 8:46 AM, Mitchell Smith <kb3...@gmail.com> wrote:



Mitchell Smith

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Mar 31, 2022, 10:46:55 AMMar 31
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Thanks Norberto.
I've had almost every chip out. I'm pretty careful about not bending pins.
I'll work on it more when I get home again.
In the mean time, I'll study the schematic a bit.

norberto.collado koyado.com

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Mar 31, 2022, 12:03:32 PMMar 31
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I think your board is having either interrupts issues or memory access issues. Also, it could be a GAL no functioning properly. I had some GALS from China, that will program without any issues. Also, it will verify as good without any issues. But when inserted on the board, the outputs will toggle at random or not toggled at all. 

Norberto

From: se...@googlegroups.com <se...@googlegroups.com> on behalf of Mitchell Smith <kb3...@gmail.com>
Sent: Thursday, March 31, 2022 7:46 AM
To: SEBHC <se...@googlegroups.com>

Mitchell Smith

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Mar 31, 2022, 7:17:00 PMMar 31
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If it's the GALs that could be a problem. They did program and verify correctly. Unfortunately, these chips came from Jameco and have now been discontinued. I checked Mouser and DigiKey but stopped there for now. Maybe I can set them up on a breadboard and test them. I just don't know enough about them.
I'm also wondering if that 74LS32 that cooked itself created another problem.

norberto.collado koyado.com

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Mar 31, 2022, 7:56:22 PMMar 31
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The GALS from Jameco are fine as I bought a lot of them and did not find any issues. As I have spares IC's I can debug here the CPU easily.

Norby

From: se...@googlegroups.com <se...@googlegroups.com> on behalf of Mitchell Smith <kb3...@gmail.com>
Sent: Thursday, March 31, 2022 4:17 PM

Mitchell Smith

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May 13, 2022, 8:16:07 PMMay 13
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Norberto, I'd like to send my Z80 board to you but I need your shipping address.
Can you send me an email?
Thanks.
Mitch

norberto.collado koyado.com

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May 13, 2022, 8:35:34 PMMay 13
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I already did! Just in case:

NORBERTO COLLADO
PO BOX 988
HILLSBORO OR 97123-0988


Norberto

From: se...@googlegroups.com <se...@googlegroups.com> on behalf of Mitchell Smith <kb3...@gmail.com>
Sent: Friday, May 13, 2022 5:16 PM

Mitchell Smith

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May 18, 2022, 9:42:36 AMMay 18
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Hi Norberto,
The board is going in the mail today. I really hate being defeated by this. I thought I had the problem nailed when I found the two bad ICs.
I looked at the clock pulses which appeared to be okay. I even have a Digilent logic analyzer but without the extender card, it's really hard to do any testing.
Please don't laugh too hard at my voltage regulator mounting. I didn't want to chop the heatsink until I made a new one.
I soldered some pins near the buss connector so I could apply power on my bench.

So when you get a chance let me know what you find. Hopefully it's not a stupid mistake on my part.

Thanks so much for giving your time and effort on this!

Mitch

norberto.collado koyado.com

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May 18, 2022, 12:09:46 PMMay 18
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Don’t worry! Hopefully we can get such board up and running soon.

 

😊

norberto.collado koyado.com

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May 28, 2022, 4:04:40 PMMay 28
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Mitch,

 

Just came from the Post Office and did not find any mail package from you. Do you have a tracking number?

 

Thanks,

Norberto

Mitchell Smith

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May 28, 2022, 5:31:48 PMMay 28
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Norberto,
I'm in Detroit until Thursday. I'll have to check when I get home. My wife mailed it while I was gone.

Mitch

Mitchell Smith

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Jun 3, 2022, 12:48:44 PMJun 3