HP-65 goes on hold after reading a card

[teenix]

(11-30-2020 11:20 AM)albertofenini Wrote:  What do you mean with 1 command or 11 commands or 8 commands ?
Do they contain specific instructions that are loaded at the power up ?
Thanks !
Take care !

Whereas the HP-67 does code handling of the program which is stored in memory, the HP-65 does it through instructions that interface to the program buffer which is a separate chip not related to other memory storage.

These are the program buffer access commands and what hexadecimal ROM address they appear in.

pointer advance - Advance the program pointer by one
1EA 47B 49B 49D 930 9F4

mark and search - subroutine handling
444 488 4FC

search for label - Looks for a label like LBL A
4A8 4AC 4AF 4C2 9A7 A09

memory insert - insert a program step at the current pointer position
4E2 A1F

memory initialize - clear the program memory
936 A3C

memory full -> a - determines if program buffer is full
B6B

Memory Delete - delete a program step
091 460 462 4B4

In your case, maybe the [Memory Full -> A] instruction is not working properly. There is only one of these codes in ROM 3 (probably 1818-0075) Through a bunch of other instructions, this is what eventually lights the G segment when the buffer is full.

It may not be the instruction however, as the program buffer and or its logic might be faulty. Hard to tell.

cheers

Tony