Memory Controller
15-56
MPC823e REFERENCE MANUAL
MOTOROLA
MEMORY CONTROLLER
15
15.5.4.2.3 Byte-Select Signals.
The MS field in the base register of the accessed memory
bank selects a user-programmable machine on the currently requested cycle. The selected
UPM only affects the assertion and negation of the appropriate BSx
signal and its timing as
specified in the RAM word. The BSx
signals are also controlled by the port size of the
accessed bank, the transfer size of the transaction, and the address accessed.
Figure 15-29 illustrates how the BSx
signals are controlled by the user-programmable
machines.
Figure 15-29. BSx
Signal Selection
UPMA
UPMB
MUX
BANK SELECTED
MS IN BRx
PS IN BRx
TSIZx
A[30:31]
BS0
BS1
BS2
BS3
LOGIC
BYTE-
SELECT
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