Downloading programs from a PC to an HP41 using a parallel interface
--------------------------------------------------------------------

This document describes how to use the HP82165 HPIL-GPIO interface to 
connect an HP41 calculator (fitted with the HP82160 HPIL interface and 
the Extended I/O module) to a Linux PC, and to download programs from the 
PC to the HP41

Throughout this document, the PC's parallel port will be named /dev/lp0 . 
Change this as appropriate, of course.

Hardware connections : 
----------------------
Connect the HPIL side of the HP82165 to the HP41's IL module in the usual 
way. 

Connect the HP82165's GPIO port to the PC using a standard PC printer 
cable and a special interface circuit. A schematic for the latter is 
given in the file hardware/Centronics-to-GPIO in the LIF utilities 
distribution



Transferring a program from the PC to the HP41
---------------------------------------------

Unlike the serial interface, there is no need to configure either the 
PC's parallel port or the GPIO interface. The default configurations are 
what is required.

On the PC type :
---------

outp41 < program_file >/dev/lp0

where program_file is the name of a file containing an HP41 program.

The input to outp41 can be piped from lifget (for example) in the 
standard way to transfer a file from a lif disk image. For example :

lifget  disk1 PROG | outp41 > /dev/lp0

will transfer the file PROG from the lif disk image disk1.

On the HP41 
-----------

GTO .. to pack program memory and create a dummy program at the END.

then execute : INP

When the program has transfered, the X-register display will return. CAT 
1 to check that the program has loaded.


----------------------------------------------
A. R. Duell, 11-Jan-2001
This file is part of the LIF Utilities distribution and has been placed
under the GNU Public License version 2.0

