CMT 64Kb RAM module for HP-71b question

[Sylvain Cote]

(10-11-2021 06:49 PM)J-F Garnier Wrote:  Ok, and what happens if you then do more successive power cycles with this configuration?
Doesn't it swing again between the bad and good memory maps? Check MEM after each power cycle.

Good thinking!

MULTIMOD with one external 32KB RAM memory module

Code:

loop
  power on → normal
  MEM → 49523 (empty machine)
  power off
end-loop

MULTIMOD with two external 32KB RAM memory module

Code:

loop
  power on → normal
  MEM → 82286 (empty machine)
  power off
end-loop

MULTIMOD with three external 32KB RAM memory module

Code:

power off
insert third external 32KB RAM memory module
power on → normal
MEM → 113543   (with MEMBUF)
power off
power on → memory lost
MEM → 115049   (without MEMBUF)
power off

Code:

loop
  power on → normal
  MEM → 98665
  power off
  power on → normal
  MEM → 115049
  power off
end-loop

MULTIMOD with four external 32KB RAM memory module

Code:

power off
insert fourth external 32KB RAM memory module
loop
  power on → normal
  MEM → 147810
  power off
end-loop

Retest: MULTIMOD with three external 32KB RAM memory module

Code:

power off
removed all modules
power on → normal
INIT 3
power off
insert three modules

Code:

loop
  power on → normal
  MEM → 65897
  power off
  power on → normal
  MEM → 115049
  power off
end-loop

re-retest: three external 32KB RAM memory module, no MULTIMOD

Code:

power off
removed MULTIMOD
loop
  power on → normal
  MEM → 115189
  power off
end-loop

reˆn test: MULTIMOD with three external 32KB RAM memory module but with POKE "2C000","1"

Code:

power off
insert MULTIMOD (no battery, power jumper removed, insert module, add batteries, add jumper)
power on → normal
INIT 3
POKE "2C000","1"
power cycle
VER$ -> HP71:1BBBB FTH:1B EDT:A KBD:C STRU:A MATH:2B JPC:F05 HPIL:1B

Code:

loop
  power on → normal
  MEM → 115057
  power off
end-loop

edit 1: added the four modules test case, one modules test case and redid the three module test case. The three modules configuration seems to be problematic, the others configuration are stable.
edit 2: I have tried the modules in different physical ports and I get the same behavior.
edit 3: testing without MULTIMOD module.
edit 4: testing with MULTIMOD module but with POKE "2C000","1"