Motorola MPC8240, Руководство пользователя

Страница: 98 / 642

2-30 MPC8240 Integrated Processor User’s Manual
Detailed Signal Descriptions
2.2.5.10.1 Memory Address Attributes (MAA[0:2])—Output
The memory attribute signals are associated with the memory interface and provide
information about the source of the memory operation being performed by the MPC8240.
They are also reset configuration input signals.
State Meaning Asserted/Negated—These signals are encoded to provide more
detailed information about a memory transaction. See
Section 15.2.1, “Memory Address Attribute Signals (MAA[0:2]),”
for a table showing these encodings.
Timing Comments Assertion/Negation—Section 15.2.2, “Memory Address Attribute
Signal Timing,” refers to timing diagrams showing the relative
timing of these signals and the rest of the memory interface.
2.2.5.10.2 PCI Address Attributes (PMAA[0:2])—Output
The memory attribute signals are associated with the PCI interface and provide information
about the source of the PCI operation being performed by the MPC8240. They are also reset
configuration input signals.
State Meaning Asserted/Negated—These signals are encoded to provide more
detailed information about a PCI transaction. See Section 15.2.3,
“PCI Address Attribute Signals,” for a table showing these
encodings.
Timing Comments Assertion/Negation—Section 15.2.4, “PCI Address Attribute Signal
Timing,” contains timing diagrams showing the relative timing of
these signals and the rest of the PCI interface.
2.2.5.10.3 Debug Address (DA[0:15])—Output
When enabled, the debug address provides software disassemblers a simple way to
reconstruct the 30-bit physical address for a memory bus transaction to DRAM and
SDRAM, ROM, Flash, or PortX. Note that most of these signals are multiplexed with other
signals (that may be inputs in their alternate function).
State Meaning Asserted/Negated—Section 15.3, “Memory Debug Address,”
describes these signals in detail, and how they are mapped to
different address bits, depending on the type of memory in use.
Timing Comments Assertion/Negation— For DRAM or SDRAM, these 16 debug
address signals are sampled with the column address and
chip-selects. For ROM, Flash, and PortX devices, the debug address
pins are sampled at the same time as the ROM address and can be
used to recreate the 24-bit physical address in conjunction with ROM
address.