Information

Enhanced Local Bus Controller
MPC8308 PowerQUICC II Pro Processor Reference Manual, Rev. 1
10-80 Freescale Semiconductor
10.4.4.4.6 Repeat Execution of Current RAM Word (REDO)
The REDO function is useful for wait-state insertion in a long UPM routine that would otherwise need too
many RAM words. Setting the REDO bits of the RAM word to a nonzero value causes the UPM to
re-execute the current RAM word up to three more times, as defined in the REDO field of the current RAM
word.
Special care must be taken in the following cases:
• When UTA and REDO are set together, TA is asserted the number of times specified by the REDO
function.
• When NA and REDO are set together, the address is incremented the number of times specified by
the REDO function.
• When LOOP and REDO are set together, the loop mechanism works as usual and the line is
repeated according to the REDO function.
• LAST and REDO must not be set together.
• REDO should not be used within the exception routine.
10.4.4.4.7 Address Multiplexing (AMX)
Address lines can be controlled by the user-provided pattern in the UPM. The address multiplex (AMX)
bits in the RAM word can choose between driving the transaction address (AMX = 00), driving it
according to the multiplexing specified by the MxMR[AM] field (AMX = 10), or driving the contents of
MAR (AMX = 11) on the address signals. The next address (NA) bit of the RAM word does not affect LA
signals, unless AMX = 00 and chooses the column address for NA = 1.
In all cases, LA[21:25] of the eLBC are driven by the five lsbs of the address selected by AMX, regardless
of whether the next address (NA) bit of the RAM word is used to increment the current address. The effect
of NA = 1 is visible only when AMX = 00 chooses the column address.
Table 10-41. MxMR Loop Field Use
Request Serviced Loop Field
Read single-beat cycle RLF
Read burst cycle RLF
Write single-beat cycle WLF
Write burst cycle WLF
Refresh timer expired TLF
RUN command RLF