Need help with XCON-8 Daughterboard

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delreycu...@gmail.com

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Nov 18, 2022, 5:49:33 AM11/18/22
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Hi, New to the world of H8 and first time working on a board for it. 
I can't seem to find documentation on the XCON-8 daughterboard that came with my Norberto 64k card (I assume you need to install XCON for all the features of the 64k card to work?) . I can tell from this thread how it's more or less constructed, but I can't see the top of the board where the GND, A14 and VCC are. Also I don't have an eprom burner and was wondering which model people are generally using to burn the 28C256. I would also love to know where the ROM image is hiding.

Thanks in advance
Jon

glenn.f...@gmail.com

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Nov 18, 2022, 6:15:47 AM11/18/22
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Hey Jon. Welcome!

 

(lengthy response below and maybe more than you needed to know!?... anyway here goes…)

 

I think you’re referring to the small adapter board that lets you install an EEPROM as a direct replacement of the original H8 ROM.  Norberto had some of these made up recently to support some work by Joe Travis - see recent post here by Joe

https://groups.google.com/g/sebhc/c/xAFDRYF1oKE

 

more on this below…

 

You should find most of what you need to build and use the 64K board here:

http://koyado.com/Heathkit/H8_8080A_64K_RAm_Brd.html

including a nice assembly guide written by David Troendle.

 

You should be able to use this board with any H8 system and ROM. With a traditional H8 set the starting address of RAM to be 8K (040.000). You can then boot HDOS or use cassette program loading, etc.

 

The board also has the functionality of the Heath HA8-8 “extended configuration” board built in, the so-called “Zero ORG” capability that allows you to address RAM all the way down to 000.000.  This of course is needed if you want to run CP/M.  If you have a Z80-based CPU board you’ve already got access to zero org but with the 8080 board you’ll need the XCON-8 ROM and need to make some jumper modifications to the board.  The instructions for doing this are in the HA8-8 documentation

https://sebhc.github.io/sebhc/documentation/hardware/H8/H8-8_As_Op_Sc.zip

 

for ROM programming some of us are using the TL866.  Mine is a “TL866 II plus” but there seem to be many variants out there.  Check amazon or other web retailers.  This product is made in china and the only caution is it can be difficult to download and/or update the firmware.  There are many “bait” clicks that you have to watch out for on the download page and the English instructions are not always clear.  Since a number of us have used this device we could help you with any questions.

 

Now, as to the ROM chip itself and the little board Norberto sent you: It’s been a while since I set up an XCON-8 board but looking at my board I see I used a 2764 UV-erasable PROM.  If you have access to one feel free to use that.  You can also still get these from vendors who support the arcade community, e.g.:

https://www.arcadepartsandrepair.com/store/integrated-circuits/eproms/2732-eprom/

 

but the little daughterboard lets you substitute a more modern EEPROM.  I don’t think there’s an instruction writeup on this but Joe Travis can probably answer any questions.

 

Good luck and feel free to post any more questions here…

 

  • Glenn

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glenn.f...@gmail.com

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Nov 18, 2022, 6:19:10 AM11/18/22
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p.s. the Heath ROM images are archived on Les’ SEBHC page here:

https://sebhc.github.io/sebhc/software.html

 

scroll down to “ROM Images”…

glenn.f...@gmail.com

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Nov 18, 2022, 6:23:58 AM11/18/22
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Sorry, one more correction: the UV erasable PROM I used is a 2732 (4K) not 2764. Sorry…

 

  • Glenn

 

 

From: glenn.f...@gmail.com <glenn.f...@gmail.com>
Sent: Friday, November 18, 2022 6:16 AM
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norberto.collado koyado.com

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Nov 18, 2022, 1:49:53 PM11/18/22
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Jon,

 

I’m giving away the little XCON-8 board as part of the H8-8080A-64KB board. For now, no need to use it if your 8080A board is working fine. It is used by Joe Travis to test out the following board: H8-DUAL-CF-CONTROLLER (koyado.com) with HDOS and CP/M.

 

For building out the 8080A-64KB memory board, here are some great videos from https://www.youtube.com/@ShadowTronBlog:

 

I will add them today to the website as well.

 

https://www.youtube.com/watch?v=xpvd9NF3iq0

HeathKit H8 - Part 1 - 64K RAM / ORG Zero card build - STB182

I begin the assembly of the H8-64K-ORG0-8080A-Z80-RAM card. Details of the card are at the URL below.http://koyado.com/Heathkit/H8_8080A_64K_RAm_Brd.htmlSTB ...

www.youtube.com

https://www.youtube.com/watch?v=5rmv6grDFBo

HeathKit H8 - Part 2 - Continuing the 64K RAM / ORG Zero card build - STB183

We continue the assembly of the H8-64K-ORG0-8080A-Z80-RAM card. Details of the card are at the URL below.http://koyado.com/Heathkit/H8_8080A_64K_RAm_Brd.html...

www.youtube.com

 

https://www.youtube.com/watch?v=NO6Ph1JtRHQ

HeathKit H8 - Part 3 - Continuing the 64K RAM / ORG Zero card build - STB184

We continue the assembly of the H8-64K-ORG0-8080A-Z80-RAM card. Details of the card are at the URL below.http://koyado.com/Heathkit/H8_8080A_64K_RAm_Brd.html...

www.youtube.com

https://www.youtube.com/watch?v=ddgijtxbIn8

HeathKit H8 - Part 4 - Continuing the 64K RAM / ORG Zero card build - STB185

We continue the assembly of the H8-64K-ORG0-8080A-Z80-RAM card. Details of the card are at the URL below.http://koyado.com/Heathkit/H8_8080A_64K_RAm_Brd.html...

www.youtube.com

 

https://www.youtube.com/watch?v=2zJ6jaaG0l0

HeathKit H8 - Part 5 - Continuing the 64K RAM / ORG Zero card build - STB192

Now that i have the remaining parts for the memory card we continue the assembly and start testing the card.http://koyado.com/Heathkit/H8_8080A_64K_RAm_Brd.h...

www.youtube.com

https://www.youtube.com/watch?v=lL4OAM7n2ZQ

HeathKit H8 - Part 6 - Finalizing the 64K RAM / ORG Zero card build - STB193

In this final build video we complete the card and test it.http://koyado.com/Heathkit/H8_8080A_64K_RAm_Brd.htmlSTB - The ShadowTron Blog Vintage computers, ...

www.youtube.com

 

https://www.youtube.com/watch?v=20I42L9FS_0

 

HeathKit H8 - Part 7 - Has the memory battery backup worked? - STB199

After being turned off for a week we power on the H8 to check if the battery backup for the 64K RAM card has worked.http://koyado.com/Heathkit/H8_8080A_64K_R...

www.youtube.com

 

Thanks,

Norberto

delreycu...@gmail.com

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Nov 18, 2022, 2:55:35 PM11/18/22
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Huge thanks for all the very helpful information. I'm putting together my Mouser order right now and ordering the TL866 II plus off Amazon ($88).
Never burned a PROM before, so this should be swell. I guess I need the UV eraser too, eh?

delreycu...@gmail.com

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Nov 18, 2022, 3:04:58 PM11/18/22
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Thanks Norby. Yes, I have the video series bookmarked. 
Btw, do you have any other sources for the 50 pin connectors? I emailed "tx83...@bellsouth.net" but no response. Worse case I could probably use the one off my 8k board.

norberto.collado koyado.com

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Nov 18, 2022, 3:41:32 PM11/18/22
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Are you referring to the 2x25 pin connectors?

 

You can get them here from the BOM: Digikey SAM1009-25-ND

 

https://www.digikey.com/en/products/detail/samtec-inc/BCS-125-L-S-HE/1100296

 

I forgot to send you the key for the hole. We 3D printed some.

 

 

 

I will put in the mail.

 

Norberto

glenn.f...@gmail.com

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Nov 18, 2022, 9:13:33 PM11/18/22
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The Samtec “HE” edge connectors are often out of stock.  The 25-pin Molex connectors (like the original Heath units) are also very difficult to find.

 

You can find the Molex ones in smaller sizes (e.g. 5s and 10s). Terry S. sometimes builds his edge connectors using 2 10s and a five (see attached). Actually a lot stronger than the original Heath approach!

 

Sorry you were unable to reach Ken Owen.  Has anyone here heard from him lately?  I’m concerned…

 

  • Glenn

 

 

Sent: Friday, November 18, 2022 3:05 PM
To: SEBHC <se...@googlegroups.com>

20201015_100816_resized_1.jpg

glenn.f...@gmail.com

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Nov 18, 2022, 9:15:53 PM11/18/22
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If you’ll be burning the older style UV-erasable PROMs like the 2732s then yes it is highly recommended to have a UV eraser.  Don’t assume that any used unit you get will have been properly erased.  If you’re using the EEPROM adapter daughterboard then no need – the EEPROms are Electrically Erasable (hence the “EE” in their name!)

 

Sent: Friday, November 18, 2022 2:56 PM
To: SEBHC <se...@googlegroups.com>

delreycu...@gmail.com

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Nov 18, 2022, 10:24:23 PM11/18/22
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I was able to find these on Mouser, but I'm not sure if they're exactly what I need. The Terry S approach looks good too. Options. I think I've found just about everything else in BOM between Mouser and Fleabay. Looking forward to building. 

delreycu...@gmail.com

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Nov 18, 2022, 10:27:21 PM11/18/22
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Thanks for the link and thanks for sending the key. Let me know what the postage is. Happy to reimburse.

Glenn Roberts

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Nov 19, 2022, 5:13:58 AM11/19/22
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Those SamTec connectors look right but I’m on my iPad and can’t bring up the BOM. if the part number matches the BOM spreadsheet you’re good. They’re not cheap. The picture shows a two-row version but don’t let that fool you. I’ve used the SamTecs on all my boards and been very pleased.

Quick question: does your backplane have the gold plated connectors or the tinned ones used on the earlier H8s?

Sent from my iPad

On Nov 18, 2022, at 10:24 PM, delreycu...@gmail.com <delreycu...@gmail.com> wrote:

I was able to find these on Mouser, but I'm not sure if they're exactly what I need. The Terry S approach looks good too. Options. I think I've found just about everything else in BOM between Mouser and Fleabay. Looking forward to building. 

Terry Smedley

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Nov 19, 2022, 9:13:06 AM11/19/22
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The Mouser link is for the correct SamTec part.  Get 'em while they're in stock!  ;-)

tas



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