Motorola MPC823e Reference Manual page 414

Memory Controller
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.
UPMA
UPMB
15-56
BANK SELECTED
MS IN BRx
MUX
Figure 15-29. BSx Signal Selection
MPC823e REFERENCE MANUAL
A[30:31]
PS IN BRx
TSIZx
BYTE-
SELECT
LOGIC
BS0
BS1
BS2
BS3
MOTOROLA