13 Dec
2006
13 Dec
'06
4:09 p.m.
Tony and Chunk,
Thank you, This kind of parity check is new to me because my mind was fixed
to the "xor" type of parity check.
What I did was that I inserted DAL17, and inserted DAL16 with "not (DAL15
xor DAL14 xor... xor DAL0)" when my controller was doing busmaster writes to
the main memory. Nobody complained. When the CPU reads the SA/IP register,
or requests the interrupt vector, If I insert DAL17, and insert DAL16 with
the signal mentioned above, vax3900 reports a machine check. This conforms
what you two said.
It seems I need to just forget the parity check thing.
vax, 9000