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View Full Version : Xerox 820-II - Kermit for CP/M 2.2



xmechanic
January 15th, 2011, 06:52 PM
Well, I finally got Hyperterm in Windows to talk to my 820-II, but only at 300 baud 7-E-1. Supposedly, you can change the baud rate for the com port or the serial printer port at startup, but I haven't been successful yet.

* B7 <cr>(sets baud rate to 1200 bps. on com port)
* B7 B <cr>(sets baud rate to 1200 bps. on serial printer port)
* H <cr>(starts machine in host terminal mode)

It seems to want to keep defaulting back to 300 bps. (screwy BIOS maybe?)

At any rate, now that I can at least exchange keystrokes back and forth, however slow, I find that I'm going to need a version of Kermit that will run on here, so I can actually transfer a file from within CP/M and get it onto the hard disc or a floppy. I can fudge it to an extent, in that I can dump a text file in the screen on the host (Windows) machine, let it load to the terminal screen on the 820-II (and into memory), and then jump out of the terminal mode, and immediately start CP/M (i.e. 'LG' <cr>) and then type SAVE 220 'test.txt' and it will save the buffer from the terminal session to a file. Problem is, it doesn't seem to assign an EOF to the file. If I read it back from the disk (i.e. TYPE test.txt), it will run through the text part of the file and then scroll it off the screen and continue on with screen after screen of t/m and similar, until I do a 'ctrl C'.

Soooooo, if anyone has the kermit program for CP/M 2.2 and any other useful utilities on 8" DSDD disk that they would want to trade around for something, please send me a P.M. ;)

I'm starting to think this thing would make an ideal 54 lb. door stop. :D:D

xmechanic
January 25th, 2011, 03:34 PM
Update: I found a patch for PIP that will allow serial file transfers on Piergiorgio Betti's archive mirror site
http://z80cpu.eu/mos/Frontpage/Itemid,1/ so if I can figure out how to apply this, maybe I won't need Kermit 80 on disk. Here's hoping... :)

Ken Vaughn
January 26th, 2011, 05:35 AM
Update: I found a patch for PIP that will allow serial file transfers on Piergiorgio Betti's archive mirror site
http://z80cpu.eu/mos/Frontpage/Itemid,1/ so if I can figure out how to apply this, maybe I won't need Kermit 80 on disk. Here's hoping... :)

What does the patch to PIP do?

When I wrote my CBIOS (CP/M 2.2 for Northstar Disk) I implemented device PUN: as serial port out and device RDR: as serial port in. This allows me to use a laptop running HyperTerminal and a serial connection (8N1-9600) to send and receive text files.

PIP PUN:=filename.typ (to send a file to the laptop, mostly listings)
PIP filename.typ=RDR: (to receive a file from the laptop -- I edit in a ctrl-Z at the end of file before sending it)

To send and receive binaries I create a disk image on the laptop using Dave Dunfield's NSI program and upload (or download) the disk image using Dunfield's NST file transfer software (specific to Northstar hard sector disks).

xmechanic
February 2nd, 2011, 08:58 AM
What does the patch to PIP do?

When I wrote my CBIOS (CP/M 2.2 for Northstar Disk) I implemented device PUN: as serial port out and device RDR: as serial port in. This allows me to use a laptop running HyperTerminal and a serial connection (8N1-9600) to send and receive text files.

PIP PUN:=filename.typ (to send a file to the laptop, mostly listings)
PIP filename.typ=RDR: (to receive a file from the laptop -- I edit in a ctrl-Z at the end of file before sending it)

To send and receive binaries I create a disk image on the laptop using Dave Dunfield's NSI program and upload (or download) the disk image using Dunfield's NST file transfer software (specific to Northstar hard sector disks).

Thanks for the reply Ken. I haven't had time to do any more on the Xerox since I wrote about the patch, so I don't really know what it is, or does. I saw something somewhere that you can re-compile PIP to allow serial port transfers. I don't know if this is for text-only, or if it will do binaries properly also. I hope I don't have to get into trying to write a custom BIOS for it, or it may end up sitting around for a lot longer. :p

glitch
February 2nd, 2011, 09:13 AM
You could get someone to send you a disk with Kermit-80 and MLOAD.COM, and build Kermit-80 for the 820-II. There's an overlay file available for the Xerox 820, which I would suspect works with the 820-II...if not, it would be a good starting point to build your own. IIRC, the 820 reads/writes SSSD and DSDD 8" floppies, so someone ought to be able to create /something/ for you (I'd offer if I had my disk imaging machine set up...currently mothballed though).

Chuck(G)
February 2nd, 2011, 09:20 AM
Not "recompiling" PIP at all. PIP implements two "user devices", INP and OUT and a patch area that extends from 103H to 1FFH (you can see it in the PIP executable filled with "(INP:/OUT:SPACE)" strings along with some "stubs" at the beginning).

Basically, one can patch over the RET instruction at 103H for INP: with a routine that interfaces to some user input device and returns a character in location 109H.

Similarly, one can replace the RET instruction at 106H for OUT: with a routine that interfaces to a user output device that accepts the character to be sent in the C register.

Patching can be performed using DDT and SAVE.

PIP is far more than a simple file-to-file copy routine. It can perform handshaking (X-on, X-off), copy sections of files, check the formation of Intel HEX files, etc.