MOTOROLA
Chapter 7. 60x Signals
7-3
Part III. The Hardware Interface
7.2 Signal Descriptions
This section describes individual MPC8260 60x signals, grouped according to Figure 7-1.
Note that the following sections brießy summarize signal functions. Chapter 8, ÒThe 60x
Bus,Ó describes many of these signals in greater detail, both in terms of their function and
how groups of signals interact.
7.2.1 Address Bus Arbitration Signals
The address arbitration signals are a collection of input and output signals devices use to
request address bus mastership, recognize when the request is granted, and indicate to other
devices when mastership is granted. For a detailed description of how these signals interact,
see Section 8.4.1, ÒAddress Arbitration.Ó
Bus arbitration signals have no meaning in internal-only mode.
7.2.1.1 Bus Request (BR)ÑOutput
The bus request (BR) signal is both an input and an output signal on the MPC8260.
7.2.1.1.1 Address Bus Request (BR)ÑOutput
Following are the state meaning and timing comments for the BR signal output in external
master mode.
State Meaning
AssertedÑIndicates that MPC8260 is requesting mastership of the
address bus. Note that BR may be asserted for one or more cycles
and then deasserted due to an internal cancellation of the bus request
(for example, due to a load hit in the touch load buffer). See
Section 8.4.1, ÒAddress Arbitration.Ó
NegatedÑIndicates that the MPC8260 is not requesting the address
bus. The MPC8260 may have no bus operation pending, it may be
parked, or the ARTRY input was asserted on the previous bus clock
cycle.
Timing Comments
AssertionÑMay occur on any cycle; does not occur if the MPC8260
is parked and the address bus is idle (BG asserted and ABB input
negated).
NegationÑOccurs for at least one cycle following a qualiÞed BG
even if another transaction is pending; also negated for at least one
cycle following any qualiÞed ARTRY on the bus unless MPC8260
asserted ARTRY and requires a snoop copyback; may also be
negated if MPC8260 cancels the bus request internally before
receiving a qualiÞed BG.
High ImpedanceÑOccurs during a hard reset or checkstop condition
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: ......