Mike: great progress!
Your best bet at getting software working is to use the H8T files. I believe it’s possible to use the .WAV files and (say) an iphone, but H8Ts are solid. They are exact digital images of the contents of the tapes – think of this as what would be captured off the UART when playing back a tape. The software you need to read them you already have – it’s built into the PAM8 monitor!
I do this using an adapter that I built using Dave Runkle’s instructions here:
but I believe you do not need to build the adapter as you can simply flip the switch on the H-8-5 board, effectively swapping the roles of the two UARTs. You can then attach a laptop or PC running a terminal emulator program and download the code. Dave has great instructions on his site (URL above).
It is useful to have the Heathkit software reference for the tape version. I’m not sure this is available in scanned form on any of our sites (?) but I have a paper copy and can provide help.
If you are not successful double back here and report on your progress and problems. I have routinely been able to reliably load the H8T images. I plan to demo this at VCF East in October…
When I finally get back to writing REMarks this would make a good one to write up!
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On Aug 30, 2021, at 10:46 PM, Mike Ladwig <mdla...@gmail.com> wrote:
I followed your suggestion and used the H-8-5 switch and had no problems loading H8T files that way -- BHBasic, some tests, etc. -- THANK YOU! Ultimately, I'd like to save that software as .wav files and use some flavor of digital audio to replace the cassette. My goal is to preserve this as an original system for the long term.
Mike: To get you started I’ve scanned Chapter 0 of the documentation, which has most of the basics. The other chapters cover the individual products (edit, dbug, asm, basic, etc) and are fairly similar to their HDOS equivalents. I’ll scan more and at some point put these on Les’ site…
For now it’s in my Google drive:
let me know how things go!
Ok great. I’ll get those soon. They go quickly.
In order to demonstrate BASIC I am hoping to be able to save and reload programs using the front panel. Unfortunately haven’t gotten that to work. When I issue the “DUMP” command and capture the serial output I get only the first record (label record). At this point BASIC just loops in a wait state… but waiting for what? What’s the handshaking model with the cassette drive? (and how can there actually be any since it’s a “dumb” device??)
So I used RTM/0 to interrupt and found the code is executing the following:
111.232 333 377 WAIT:IN 371 ; Cassette control port
111.234 247 ANA A ; test bits
111.235 372 232 111 JM WAIT ; loop ‘til bit 8 clear
The AF register shows 205 202.
I believe the 8251 is being operated in synchronous mode? It is looping waiting for the high bit of the control port to be cleared. Waiting for a SYNC character? There’s discussion of the 8251 synchronous mode in the H-8-5 manual. Reading through that…
Anyway I’m still trying to understand how the handshaking works with cassette use.. any enlightenment would be welcome!
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Thanks Mike. My problem was actually a hardware one. The software was waiting for the DSR line to go high. On the H-8-5 board there’s actually a little 5 second timer that holds DSR low while the tape motor spins up (which also provides a nice gap between files on the tape). For some reason the timer wasn’t working. I’d like to tell you I fixed the board but I actually swapped in a spare one that I happen to have!
Anyway, now I can accurately save and restore programs!