[sdiy] how you got started with your current µC?

[Rick Jansen]

On 24/09/2015 20:12, Rick Jansen wrote:

> Plessey miproc (assembler, using DEC's assembler as a cross assembler)

There is some DIY attached to this one. The miproc is (was) an interesting µP in those 
days, it was 16-bit already, and designed for ultra-fast operation. It had separate data- 
and program memory, and ALL instructions were same length, and has the same execution 
time, except the multiplication and divide, which were handled by a separate board.

I did a project on it as part of my thesis, so it is some time ago :-)

The DIY: there was an assembler available from Plessey for Miproc, but it ran on RT-11 
only, a single-user OS. The PDP it was "connected" to was running RSX, for multi-user 
purposes. I could not have the machine in RT-11 mode, so basically I was without its 
proper assembler and code generator.

Second problem: Miproc was built-in into a PDP rack, and connected via a serial 
connection. However, no drivers on RSX were available to connect... What Miproc did have 
was a serial connection intended to hook-up a Teletype. Yes, one of those mechanical 
300(?) baud extremely noisy typewriters, with a papertape reader.

RSX did have, however, a PDP-11 MACRO assembler. What I did was define a macro for each 
instruction of the Miproc. The instruction set was simple enough to not cause any problems 
there. Of course any generated binaries were useless, but the generated output (printer) 
listings contained enough information to extract the actual (octal) machine codes from. 
With a Pascal program I read the output listings intended for the printer, and generated 
HEX files.

Sooo, I found TWO Teletypes. One connected to RSX, one to Miproc. Ran the assembler, 
extracted the HEX codes with my Pascal program, punched the generated data in papertape 
from RSX, took the papertape to the Miproc teletype, read the papertape, and could run the 
program.  I still have that roll of papertape, and the paper output roll.

Anyone complaining about their Wifi? Hm?

rick