Motorola MVME2300 Series - Manual (Page 198)

3-36 Computer Group Literature Center Web Site
Falcon ECC Memory Controller Chip Set
3
The output of the chip prescale counter is used by the
refresher/scrubber and the 32-bit counter. After power-up,
this register is initialized to $42 (for 66MHz).
por por is set by the occurrence of power-up reset. It is cleared
by writing a 1 to it. Writing a 0 to it has no effect.
ECC Control Register
refdis When set, refdis causes the refresher and all of its
associated counters and state machines to be cleared and
maintained that way until refdis is removed (cleared). If a
refresh cycle is in process when refdis is updated by a
write to this register, the update does not take effect until
the refresh cycle has completed. This prevents the
generation of illegal cycles to the DRAM when refdis is
updated.
rwcb rwcb, when set, causes reads and writes to DRAM from
the PowerPC 60x bus to access check-bit data rather than
normal data. The data path used for this mode is DH24-31
for check-bit data controlled by the upper Falcon, and
DL24-31 for check-bit data controlled by the lower
Falcon. Each 8-bit check-bit location services 64 bits of
normal data. The 64 bits of data are all within the same
Falcon. Each Falcon provides every other 32 bits of data
in the normal mode. The following figure shows the
relationship between normal data and check-bit data.
Address $FEF80028
Bit
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Name
0 0 0 0 0 refd
is
rwcb de
rc 0 0 0 0 scien tie
n sien mi
en 0 0 0 0 0 0 0 mc
ken
Operation
R R R R R R/W R/W R/W R R R R R/W R/W R/W R/W
READ ZERO
R R R R R R R R/W
Reset
X X X X X 0 PL 0 PL 1 PL X X X X 0 PL 0 PL 0 PL 0 PL
X
X X X X X X X 0 P
L