HP-21MX bootstrapping?

Brent Hilpert hilpert at cs.ubc.ca
Tue Feb 19 04:06:33 CST 2008

Tim Riker wrote:
> http://www.cs.ubc.ca/~hilpert/e/HP21xx/software.html
> has an "ASCII Binary Loader" That might be useful, but alas, I have not
> yet gotten it to assemble. Working on it some. :)

Just a comment on that, it was written for a requirement similar to yours: to
download into the HP machine over a serial line from a modern machine
running a terminal program. Please note that the protocol/load format is no
relation to the HP Basic-Binary-Loader format: if you wish to use it you'll
have to convert your binaries to it's language (tis pretty simple but more work
none-the-less). The advantage of it is everything pertinent goes over the
serial line in printable ASCII, and it ignores everything else.

(It works fine for me but I created all my own support stuff (cross-assembler &
simulator) to work with it. As it was written to assemble under my own
assembler, there may/will be some minor diffs from the HP asm standards, but
the machine code is there in the listing to toggle it in without having to assemble

Based on other's responses I suspect you'll find a solution with an original HP loader.

Another possibility might be to modify the old HP teleprinter loader:


It uses the HP BBL load format.
It was for loading over a serial line from the paper tape reader on a teletype,
but uses a 12531A IO interface, which was a bit-bang interface. It could be
converted for the 12531B/C by, in short, replacing the ReadByte routine with
instructions appropriate for the 12531B/C.

(Also note that my experience in this is limited to playing with a 2116 system).

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