10-76
MPC8260 PowerQUICC II UserÕs Manual
MOTOROLA
Part III. The Hardware Interface
10.6.4.1.3 General-Purpose Signals (G
x
T
x
, GO
x
)
The general-purpose signals (GPL[1Ð5]) each have two bits in the RAM word that deÞne
the logical value of the signal to be changed at the rising edge of T1 and/or at the rising edge
of T3. GPL0 offer enhancements beyond the other GPLx lines.
GPL0 can be controlled by an address line speciÞed in M
x
MR[G0CL
x
]. To use this feature,
set G0H and G0L in the RAM word. For example, for a SIMM with multiple banks, this
address line can be used to switch between banks.
10.6.4.1.4 Loop Control
The LOOP bit in the RAM word (bit 24) speciÞes the beginning and end of a set of UPM
RAM words that are to be repeated. The Þrst time LOOP = 1, the memory controller
recognizes it as a loop start word and loads the memory loop counter with the
corresponding contents of the loop Þeld shown in Table 10-36. The next RAM word for
which LOOP = 1 is recognized as a loop end word. When it is reached, the loop counter is
decremented by one.
Continued loop execution depends on the loop counter. If the counter is not zero, the next
RAM word executed is the loop start word. Otherwise, the next RAM word executed is the
one after the loop end word. Loops can be executed sequentially but cannot be nested.
10.6.4.1.5 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 to cause the UPM to reexecute the current RAM word up to three times,
according to Table 10-35.
Special care must be taken in the following cases:
¥
When UTA and REDO are set together, PSDVAL is asserted the number of times
speciÞed 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 should not be set together.
¥
REDO should not be used within the exception routine.
Table 10-36. M
x
MR Loop Field Usage
Request Serviced
Loop Field
Read single-beat cycle
RLFx
Read burst cycle
RLFx
Write single-beat cycle
WLFx
Write burst cycle
WLFx
Refresh timer expired
TLFx
RUN
command
RLFx
Summary of Contents for MPC8260 PowerQUICC II
Page 1: ...MPC8260UM D 4 1999 Rev 0 MPC8260 PowerQUICC II UserÕs Manual ª ª ...
Page 66: ...lxvi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA ...
Page 88: ...1 18 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 120: ...2 32 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part I Overview ...
Page 138: ...Part II iv MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II Configuration and Reset ...
Page 184: ...4 46 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part II ConÞguration and Reset ...
Page 202: ...Part III vi MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 266: ...8 34 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 382: ...10 106 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 392: ...11 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part III The Hardware Interface ...
Page 430: ...Part IV viii MOTOROLA Part IV Communications Processor Module ...
Page 490: ...14 36 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 524: ...17 10 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 556: ...18 32 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 584: ...19 28 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 632: ...21 24 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 652: ...22 20 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 668: ...23 16 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 758: ...27 28 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 780: ...28 22 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 874: ...29 94 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 920: ...31 18 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Part IV Communications Processor Module ...
Page 980: ...A 4 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA Appendixes ...
Page 1002: ...Index 22 MPC8260 PowerQUICC II UserÕs Manual MOTOROLA INDEX ...
Page 1006: ......