Re: 6809 / 6702 puzzle

From: Rhialto <>
Date: Sat, 21 Apr 2012 10:01:01 +0200
Message-ID: <>
Ruud has just brought his SuperPET here for research.

Preliminary observations:

- Some keys on the keyboard don't work. This makes typing commands a bit
  difficult. Can one clean the keyboard by taking it apart or is this
  likely to be more difficult?
  I do have some other 8032-type PETs whose keyboard I could swap in.

- Inside there is the single-board version of the SuperPET expansion.
  No separate 6702 board.

- Initial value of EFE0-EFE3: D6.

- From (a remark on) the schematic at
  it appeared that the 6702 might be addressable on all addresses EFex
  (where e is any even digit and x is any digit). This doesn't appear to
  be true, but the EFex and EFox (o for any odd digit) do read out
  differently.  EFex seems to be FF (except for EFE0-EFE3) EFox seems to
  change on some occasions (possibly when EFE0 changes).

- Reading from EFE0 doesn't change the previous value; the state of the
  dongle doesn't change on just reads. So far, it seems to change only
  when you write in a *different* value, that also isn't 00.

___ Olaf 'Rhialto' Seibert  -- There's no point being grown-up if you 
\X/ rhialto/at/    -- can't be childish sometimes. -The 4th Doctor

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Received on 2012-04-21 09:00:05

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