[MiNT] Test for ST-ESCC fails on TT

[Joerg_Westheide@su.maus.de (Jörg Westheide)]

Hi Mario!

MB>I have now been able to compile the MiNT kernel, and so the first
MB>thing I looked into is how, on the TT, MiNT detects an "ST-ESCC" even
MB>though it is not present.
Yes, that's a known and fixed bug (Frank got the patch, only the new beta is
missing)

MB>I do not know exactly what impact this has on the operation of MiNT
MB>but presumably some serial port functions don't work properly. I hope
MB>this has something to do with why MiNT never detects the a dropped
MB>carrier, and will not negate DTR properly on a serial port.
I don't know the impacts too, but I think there's a connection between the
failing detection and these problems.

MB>Anyway the problem is that on the TT the memory locations read as a
MB>test for the presence of the ST-ESCC hardware do not generate a bus
MB>error, and so the test thinks an ST-ESCC is present.
Yes, that's exactly the problem

MB>On the TT these locations seem to read all 1's. Perhaps the test can
MB>be improved along those lines, if the ST-ESCC never really reads all
MB>1's. If the ST-ESCC registers do, however, sometimes read as all 1's
MB>then a different approach would be needed.
There's one register that always reads 0. The new detection will only detect
an ST-ESCC if it reads a 0 from that register

Bye

                Joerg