Can the HP 41 Read HP 65 Programs


I continue to try and debug/fix my newly acquired 65. If I knew the 65 can write a program (to be read by the 41), it might help me narrow down some things.


IIRC, the HP-41 can read HP-67/97 cards; but no HP-65 cards. I think the recording format is the same, but the data (op codes) are possibly meaningless... However, trying will not hurt.


The HP-65 used six bit op codes to store its programs; the HP-67 and 97 used 8 bit codes. No machine after the 65 could read its card data (programs or registers). Sorry.

Trivia - the 65's program storage was a dynamic shift register so the program was constantly circulated around same. There was no addressing for the data. The way a particular instruction was found was that a particular index value (all zeros if I recall) was stored *once* in the register. When that came by the read circuit, a counter was started. When the appropriate number of values clocked by after that, the desired value was read.

Of course, if more than one index value ended up in the program store the data read would be randomly chosen as so many values after either one. I'm still boggled that one of the old HP-65 Users Club members figured this all out on his own without any logic analyzers, oscilloscopes, internal documentation, etc.

Possibly Related Threads...
Thread Author Replies Views Last Post
  Does the HP Prime really compiles the user programs? CompSystems 3 1,141 12-13-2013, 01:55 PM
Last Post: Mike Morrow
  HP-41(CL): The easiest way to transfer FOCAL programs from a Linux PC to the HP-41 Geir Isene 13 2,574 12-05-2013, 02:40 AM
Last Post: Hans Brueggemann
  HP Prime: Lists in programs Alberto Candel 7 1,636 12-04-2013, 02:16 AM
Last Post: Alberto Candel
  HP Prime: FLOOR, iPart , and their use in programs Alberto Candel 6 1,206 12-01-2013, 10:17 PM
Last Post: Alberto Candel
  [HP-41][HP-71B][HP-75C/D][HP-IL] Found a mother-lode of programs on rdj 2 818 11-26-2013, 05:31 PM
Last Post: rdj
  HP Prime: matrices in programs, in need of help Alberto Candel 9 1,435 11-26-2013, 01:33 AM
Last Post: cyrille de Brébisson
  HP Prime: password protection for programs Davi Ribeiro de Oliveira 2 716 11-22-2013, 12:45 PM
Last Post: Geoff Quickfall
  Question about transfering programs to the HP Prime Namir 10 1,524 11-17-2013, 04:01 PM
Last Post: Namir
  HP Prime: do not send programs and shuts down by pressing Apps Davi Ribeiro de Oliveira 1 579 11-12-2013, 11:05 AM
Last Post: Joseph Ec
  Grouping programs on the HP Prime Michael de Estrada 11 1,701 11-04-2013, 01:38 PM
Last Post: Damien

Forum Jump: