
8-24
G2 PowerPC Core Reference Manual
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MOTOROLA
Signal Descriptions
For external control instructions (
eciwx
and
ecowx
), core_tbst_out is
used to output EAR[28], which is used to form the resource ID
(core_tbst_out||core_tsiz[0:2]).
Assertion/Negation—The same as core_a_out[0:31].
High Impedance—The same as core_a_out[0:31].
Timing Comments
8.3.4.4
Transfer Code (core_tc[0:1])—Output
The core_tc[0:1] consists of two output signals on the G2 core. Following are the state
meaning and timing comments for the core_tc[0:1] outputs.
State Meaning
Asserted/Negated—Represents a special encoding for the transfer in
progress (see Table 8-9).
Timing Comments
Assertion/Negation—The same as core_a_out[0:31].
High Impedance—The same as core_a_out[0:31].
8.3.4.5
Cache Inhibit (core_ci)—Output
Following are the state meaning and timing comments for the core_ci output.
State Meaning
Asserted—Indicates that a single-beat transfer is not cached,
reflecting the setting of the I bit for the block or page that contains
the address of the current transaction.
Negated—Indicates that a burst transfer in progress will allocate a
line in the G2 core data cache.
Timing Comments
Assertion/Negation—The same as core_a_out[0:31].
High Impedance—The same as core_a_out[0:31].
8.3.4.6
Write-Through (core_wt)—Output
Following are the state meaning and timing comments for the core_wt output.
State Meaning
Asserted—Indicates that a single-beat transaction is write-through,
reflecting the value of the W bit for the block or page that contains
the address of the current transaction.
Table 8-9. Encodings for core_tc[0:1] Signals
core_tc(0:1)
Read
Write
0 0
Data transaction
Any write
0 1
Touch load
—
1 0
Instruction fetch
—
1 1
Reserved
—
F
Freescale Semiconductor, Inc.
n
.