Note on Ethernet Board (CSD142 Rev B) Debugging

Test of local communication between 68000 and Z80, and of Z80's memory.

The checkout kit comprises of 2 programs, one each to run in the 68000
and the Z80, all residing in proms (2*2716 for the 68000, assembled
from file CHECK.ASM, 1*2732 assembled from file CHECK.Z80).

The machine in which the test is to be carried out requires processor
board, ethernet board, and VDU.  Memory board and tap connection are
not necessary.

When the machine is switched on or reset, the VDU should say "Starting",
and then a message will appear stating that the CSR (the ether board
link status register as seen by the 68000) is OK or not as expected.
If not as expected, there is a fault on the ether board.

If at any time the message "unexpected trap ..." or "address error ..."
appears, this usually indicates a faulty processor board, the same goes
for "Bus error ...", unless the address specified is in the range 7FFFC
to 7FFFF, which would indicate a failure of the ether board to respond
to an access by the 68000.


Next, whatever you type at the VDU keyboard should be echoed (except
a few special characters mentioned below).  The echoing involves the
character being written into the ether station and back out again
before appearing on the VDU screen.

Special characters:

ctrl-Y  resets the machine and restarts the test.
'_'     expects a hex number, and sends that character, which should also
        be echoed (if it constitutes a non-priting character, it will be
        echoed in the form "_xx".
'^'     is the same as '_', only characters are sent as control rather
        than data.  The ether board will echo those as well, and anything
        received will be echoed as "^xx".
*note*  that typing '_' or '^' will NOT echo immediately, first you have
        to type a hex number followed by a non-hex character.
'M'     invokes the Z80's memory test.  It should echo "Memory test", and
        then start to print out lines of 6 numbers.  These are:
        previous pattern, current pattern, late error count,
        immediate error count, picked bits, dropped bits.
        The first two should, if all is well, be a shifting pattern, the
        other four should be zero.  The test will continue until you
        hit ctrl-Y or the reset button.
'S'     is special and should not be used.

Recommended sequence of testing is first to check out the echoing.
Just type any sequence of printing characters except upper-case S, M,
'^', or '_', and observe that echo is taking place correctly.
Then make sure all the bits are getting through by trying _00, _01, _02,
_04, _08, _10, _20, _40, _80, which should echo as _00, _01, _02, _04,
_08, _10, <space>, '@', and _80.  Next try control characters by typing
^00, ^01, etc, up to ^80, which should all echo as typed.

Next type 'M' and watch the memory test go.

RWT Jan 1986