H8-Z5-4 status!

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norberto.collado koyado.com

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Aug 6, 2022, 5:43:57 PMAug 6
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All,

 

I have been stressing this design to be sure it is as solid as it can get. I just found that after loading the “EXBASIC5.H8T” file, pressing “GO”, I do not get nothing on the 8251A serial port after pressing the space bar several times. The new H8CHESS.H8 runs fine on the same 8251A console.

 

If I replace the board with my previous H89-Z5-4 board, then EXBASIC5.H8T” runs fine on the 8251A console.

 

I did replace most of the components without any progress.

 

Any ideas?

 

Norberto

Joseph Travis

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Aug 6, 2022, 6:05:39 PMAug 6
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If the 8250 is at I/O address 350Q, EXBASIC4,5,6 will default to the 8250 instead of the 8251.



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norberto.collado koyado.com

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Aug 6, 2022, 7:01:09 PMAug 6
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That fixed the issue! My bad!  Now I feel more relax that we have a fully functional board.

 

Do you have a document that lists the games and which console to use? I will like to add that to the website.

 

Thanks,

Norberto

Joseph Travis

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Aug 6, 2022, 8:34:04 PMAug 6
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EXBASIC4,5,6 are the only ones that I know of that do that.  Glenn may know of others.


Glenn Roberts

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Aug 7, 2022, 6:21:11 AMAug 7
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We have an interesting situation now that this new board has console ports from both the H8-5 and H8-4 worlds. All of the early Heath cassette software was written for the console as an H8-5, but at some point as the H8-4 boards were introduced the console drivers were programmed to recognize which board was installed. 

What I think we concluded (see previous discussions on this) was that The Heath software considered the H8-4 to be the preferred console, if one was detected. Presumably this is because at that time the H8-4 was new, more expensive and sophisticated.  They recognized that users would want to keep their old H8-5 boards to do cassette i/o but assumed the console function would migrate to the new board. I’m still not completely comfortable with this conclusion, since the “space bar” trick ought to let either one be detected at runtime?

From trial and error I believe we concluded this change to the console driver occurred around release 4 so versions 4, 5, and 6 would direct console I/O to the 8250 on port 350Q if one was detected.  This would affect all of the programs (eg editor, debugger, etc) as they shared the common console code. I did some disassembly of that console code but never came up with a definitive answer.

David Troendle may have source listings for the cassette-based software and I believe he’s keeping an eye out for that as he organizes things after his recent move.

So bottom line as I understand it: to run the most recent versions of the cassette software attach the console to the 8250 at port 350Q, irq3 (or disable that port and use the 8251)


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On Aug 6, 2022, at 8:34 PM, Joseph Travis <jtravi...@gmail.com> wrote:



norberto.collado koyado.com

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Aug 7, 2022, 4:15:22 PMAug 7
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Here is a picture of the old H8-5 and the new H8-Z5-4 board.

 

The 8250 console port and the 8251 console port can be disabled with a jumper on the new board.

 

Thanks,

Norberto

H8-5-THE-NEW-THE OLD.jpg

Glenn Roberts

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Aug 7, 2022, 4:45:55 PMAug 7
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Amazing that after 45 years we can produce a modern equivalent that’s faithful to the original design but adds some engineering enhancements and modern touches. We’ll done…

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On Aug 7, 2022, at 4:15 PM, norberto.collado koyado.com <norberto...@koyado.com> wrote:



norberto.collado koyado.com

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Aug 7, 2022, 5:20:46 PMAug 7
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Agree! Also, once the VCO is calibrated properly, you can still read the old H8 tapes after 45 years.

 

I uploaded latest files to the website. What is pending is the calibration guide and BOM.

 

Link: http://koyado.com/heathkit/New-H8-Website/h8-z5-4-serial-console-cassette-io.html

 

Thanks,

Norberto

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