HP-41 printer interface question. (To the M-code gurus out there)



#2

Hi all,

I've read almost every line of info regarding HP-41 <> PRINTER interface.

Still a (great) doubt remaining; quoting William Doug Wilder:

"It makes me wonder how the carry
bit gets set, what is the hardware sequence that sets carry?"

So far I've been unable to figure out how instructions h'003, h'043 & h'083 handle the carry flag *into* NUT CPU.

These are instructions decoded and executed by the Peripheral chip, issued right after the SELP 9 instruction.

Any comment will be much appreciated.

Thanks for your attention

Diego


#3

For the flag tests of the "intelligent peripheral" chips, the peripheral puts the flag value onto the ISA line during bit time 0. The CPU copies that to the carry flag.

This is for any instruction of the form hexadecimal x03, x43, x83, or xc3 (x being 0, 1, 2, or 3), in a sequence following a peripheral select instruction (x24, x64,xa4, xe4). It does not apply to the "normal" x03, x43, x83, xc3 instructions, which are jump instructions.


#4

Hi Eric,

Thanks a lot for your reply... :-) now back to work!

Cheers.

Diego


Possibly Related Threads...
Thread Author Replies Views Last Post
  HP-41(CL): The easiest way to transfer FOCAL programs from a Linux PC to the HP-41 Geir Isene 13 1,688 12-05-2013, 02:40 AM
Last Post: Hans Brueggemann
  HP PRIME: APP program code DISAPPEARS !! Joseph Ec 0 296 11-25-2013, 11:35 AM
Last Post: Joseph Ec
  Non-Prime question alert: Hp-41 and synthetic instructions Marcel Samek 11 1,238 11-04-2013, 09:31 PM
Last Post: sjthomas
  Virtual printer for a virtual 41 Mike (Stgt) 6 728 10-30-2013, 10:32 AM
Last Post: Mike (Stgt)
  HP48GX Interface to a PC John W Kercheval 7 795 09-29-2013, 10:53 AM
Last Post: John W Kercheval
  Where to the 32-bit version of User Code Utiltiy for HP-41 ? Olivier (Wa) 2 408 09-26-2013, 01:55 AM
Last Post: Olivier (Wa)
  A HP42S Code Editor Andreas 9 991 09-22-2013, 03:17 AM
Last Post: Andreas
  HP Prime "Symb" interface (bug?) Han 8 822 09-13-2013, 12:48 PM
Last Post: Chris Tvergard
  Virtual HP-IL Video Interface ILVideo the 2nd! Christoph Giesselink 3 550 08-15-2013, 06:49 PM
Last Post: Sylvain Cote
  Dynamic Gaussian Quadrature code in Excel VBA Namir 4 576 07-30-2013, 07:37 PM
Last Post: Namir

Forum Jump: