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G2 PowerPC Core Reference Manual
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MOTOROLA
Signal Descriptions
Negation/High Impedance—Occurs on the third bus clock cycle
after core_ta is asserted, if core_dpe_tre is asserted. If core_dpe_tre
is negated, core_dpe is always driven.
8.3.7.3.1
Data Parity Error Output Enable (core_dpe_oe)—Output
core_dpe_oe is an output-enable indicator to its corresponding bus signals. Following are
the state meaning and timing comments for core_dpe_oe.
State Meaning
Asserted—Indicates that the core is driving a valid core_dpe.
Negated—Indicates one of the following two conditions:
If core_dpe_tre is negated, negated core_dpe_oe indicates that the
core is not driving a valid core_dpe value.
If core_dpe_tre is asserted, negated core_dpe_oe indicates that
core_dpe is in the high-impedance state.
Timing Comments
Assertion—Asserted on the second bus clock cycle after core_ta is
asserted to detect the incorrect parity, unless core_ta is canceled by
an assertion of core_drtry or core_artry (in certain cases).
Negation—Occurs on the third bus clock cycle after core_ta is
asserted.
Note that the negation of core_dpe_oe may force core_dpe to the
high-impedance state, if core_dpe_tre is asserted.
8.3.7.3.2
Data Parity Error High-Impedance Enable (core_dpe_tre)—Input
Following are the state meaning and timing comments for core_dpe_tre. core_dpe_tre is a
high-impedance enable signal on the G2 core and can be used to create a three-statable
version of core_dpe externally. The resulting core_dpe signal functions similar to a 60x bus
signal when core_dpe_tre is asserted.
State Meaning
Asserted—core_dpe_oe controls whether the data parity error output
signal is driven or forced to a high-impedance state.
Negated—Indicates that core_dpe is always driven.
Timing Comments
Assertion/Negation—Must be set up prior to negation of the
core_hreset signal and remain stable during core operation. This is a
static configuration.
8.3.7.4
Data Bus Disable (core_dbdis)—Input
The core_dbdis signal is an input signal (input-only) on the G2 core. Following are the state
meaning and timing comments for the core_dbdis input.
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