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Jan Waclawek
11/21/11 03:15
  11/21/11 03:18

Read: 418 times

#184842 - external execution in '41/'42
Responding to: Richard Erlacher's previous message
Richard Erlacher said:
Those 8041/8042 chips are hard-coded ROM-based chips, hence won't do much, as, IIRC, they don't work with external memory.

UPI-41A/41AH/42/42AH USER'S MANUAL said:

The UPI family has an External Access mode (EA) which puts the processor into a test mode. This mode allows the user to disable the internal program memory and execute from external memory. External Access mode is useful in testing because it allows the user to test the processor’s functions directly. It is only useful for testing since this mode uses D0–D7, PORTS 10-17 and PORTS 20–22.

The rest of this chapter goes on with details how to demultiplex the port values (including the data "exchange" port) from the external memory access. In this aspect, it appears to be quite similar to the external execution of 8048 (or 8035, if you want).

I admit it is not trivial, but appears doable. Unfortunately, I don't have the time to prove it.


List of 12 messages in thread
Sourcing historic uCs      Greg Kennedy      11/20/11 12:28      
   Vintage MCUs      Michael Karas      11/20/11 13:03      
      8041      Jan Waclawek      11/20/11 13:42      
         Unfortunately ...      Richard Erlacher      11/20/11 16:00      
            external execution in '41/'42      Jan Waclawek      11/21/11 03:15      
               I don't doubt what you said ...      Richard Erlacher      11/21/11 09:45      
   Have some old 8748, 8749 and V20 chips      Bert Van Den Berg      11/20/11 15:27      
      I've got some other old MCU and MPU chips ...      Richard Erlacher      11/20/11 16:08      
   Can you program them      Aubrey Kagan      11/21/11 13:59      
      Some of us have those ... even the programmables      Richard Erlacher      11/21/11 21:27      
   If I can find 'em ...      Richard Erlacher      11/21/11 21:30      
   seems still live      Stefan KAnev      11/22/11 08:03      

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