[Coco] PT68K-4

[Barry Nelson]

I found this information about MONK and the PT68K and the documentation at the links below…

At Power On, MONK will beep the speaker and then look for a Terminal connected to COM1. If not found it will proceed to initialize for a PC keyboard and initialize the previoup selection made by the "X" command. If no selection exits it will try to find a display adaptor and initialize it. If for some reason you get a blank, screen enter "X" and the character "M" for MGA, "C" for CGA, "E" for EGA or "V" for VGA to tell MONK the type of Display you want. If a Terminal is found, it will try 19.2K baud rate, and then default to 9600. Monk will accept input from either the PC keyboard or the Terminal keyboard; however, programs using traps for I/O will use the selected I/O devices.

Documentation

http://bitsavers.trailing-edge.com/pdf/peripheralTechnology/PT68K4/

Disk images

http://bitsavers.trailing-edge.com/bits/PeripheralTechnology/


 
On Sep 20, 2015, at 1:18 AM, coco-request at maltedmedia.com wrote:

> Date: Sat, 19 Sep 2015 23:30:20 -0500
> From: Dave Philipsen <dave at davebiz.com>
> To: CoCoList for Color Computer Enthusiasts <coco at maltedmedia.com>
> Subject: [Coco] PT68K-4
> Message-ID: <55FE365C.8060808 at davebiz.com>
> Content-Type: text/plain; charset=utf-8; format=flowed
> 
> This is a fairly lengthy explanation/question about the PT68K-4 so if 
> you don't know what that is or you're not interested feel free to stop 
> here and go on to the next message.
> 
> I have an old PT68K-4 motherboard that I bought somewhere around 25 
> years ago. At one time I had it up and running OSK V2.4 with a hard 
> drive, floppy, ET4000 VGA card, and a modem.  Well, along the way 
> everything but the motherboard and the original manual has disappeared.  
> It's been so long since I used this machine that I don't even remember 
> what the boot screen looked like.  So I found an old XT power supply, a 
> new HD floppy drive, a power LED, and a HALT LED and hooked them all 
> up.  The 'BIOS' EPROMs on this board are labeled 'MONK' which is the 
> monitor that was used for booting OSK. I believe 'HUMBUG' EPROMs were 
> used for other operating systems. The board has the full 4MB of memory 
> and I went ahead and 'wiggled' pretty much all of the chips of the 
> motherboard in their sockets including the RAM chips.  Right now I do 
> not have a VGA card but I'm waiting on receipt of an ISA bus ET4000 VGA 
> card from a gracious doner in Australia.
> 
> When I turn on the power supply the POWER LED lights and the HALT LED 
> lights momentarily then goes out (which I'm pretty sure is normal).  I 
> also get a 'beep' out of the speaker which I believe is a very good 
> sign.  So I put a 'scope on the *CS line on the first DUART which 
> controls COM1 and COM2 and I see regular negative going strobe pulse 
> there indicating that the monitor is looking for input from a serial 
> port (presumably COM1).  Also, the schematic shows me that the 'beep' I 
> hear when I power up the motherboard comes from a single-bit output on 
> the DUART which to me means that the CPU is talking to the DUART.  I 
> also 'scoped the pin on the DUART where the recv/xmt clock comes in from 
> a can oscillator.  Rough calculations from my 'scope say the frequency 
> is about 3.7 MHz which is corrrect (oscillator is 3.6864 MHz).
> 
> Here's the question:  Right after reset and the speaker beeps there is a 
> quick little burst of data that comes out of the TxD on the DUART.  I 
> can see the burst on my 'scope (it might be just one or two characters) 
> on the TxD pin of the DUART and I can see it on the TxD pin of the COM1 
> connector at RS232 levels.  When I hook this up to a COM port on my PC 
> with PuTTY running in serial port mode I get nothing intelligible coming 
> in to the serial port on the PC.  I've tried 200, 600, 1200, 2400, 9600, 
> 19200, and 38400 bps on PuTTY but I can't see anything other than some 
> garbage characters.  Can anyone tell what I should be seeing and what 
> the monitor program (MONK) expects to be seeing from me?
> 
> Dave Philipsen
> 
> 
> 
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