
MOTOROLA
Chapter 8. Signal Descriptions
8-39
Signal Descriptions
The assertion of core_tea causes the negation of core_dbb_out in the
next clock cycle. However, data entering the GPR or the cache is not
invalidated.
Negated—Indicates that no bus error was detected
.
Assertion—May be asserted while core_dbb_out is asserted, and the
cycle after core_ta during a read operation. core_tea should be
asserted for one cycle only.
Negation—core_tea must be negated no later than the negation of
core_dbb_out.
Timing Comments
8.3.9
Interrupt and Checkstop Signals
Most interrupt and checkstop signals are input signals that indicate when exceptions are
received, when checkstop conditions have occurred, and when the core must be reset. The
G2 core generates the output signal core_ckstp_out when it detects a checkstop condition.
For further detailed description of these signals, see Section 9.7, “Interrupt, Checkstop, and
Reset Signals.”
8.3.9.1
External Interrupt (core_int)—Input
Following are the state meaning and timing comments for the core_int input.
State Meaning
Asserted—The core initiates an interrupt exception if MSR[EE] is
set; otherwise, the core ignores the interrupt. To guarantee that the
core takes the external interrupt, core_int must be held asserted until
the core takes the interrupt.
Negated—Indicates that normal operation should proceed. See
Section 9.7.1, “External Interrupts.”
Timing Comments
Assertion—May occur at any time and may be asserted
asynchronously to the input clocks. The core_int input is
level-sensitive.
Negation—Should not occur until the external interrupt exception is
taken.
8.3.9.2
Critical Interrupt (core_cint)—Input: G2_LE Core-Only
Following are the state meaning and timing comments for the core_cint input on the G2_LE
core. See Section 5.5.10, “Critical Interrupt Exception (0x00A00)—G2_LE Only,” for
more information.
State Meaning
Asserted—The core initiates an interrupt exception if MSR[CE] is
set; otherwise, the core ignores the interrupt. To guarantee that the
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