System Management Interrupt; Machine Check Interrupt - IBM PowerPC 604 User Manual

7 .2.9.1 Interrupt (INT)-lnput
The interrupt (INT) signal is input only. Following are the state meaning and timing
comments for the INT signal.
State Meaning Asserted-The 604 initiates an interrupt if MSR[EE] is set;
otherwise, the 604 ignores the interrupt. To guarantee that the 604
will take the external interrupt, the INT signal must be held active
until the 604 takes the interrupt; otherwise, the 604 will take an
external interrupt depending on whether the MSR[EE] bit was set
while the INT signal was held active.
Negated-Indicates that normal operation should proceed. See
Section 8.8.1, "External Interrupts."
Timing Comments
Assertion-May occur at any time and may be asserted
asynchronously to the input clocks. The INT input is level-sensitive.
Negation-Should not occur until interrupt is taken.
If deterministic cycle sequencing is required (for example, in multiple processor systems
operating in lock step), the INT signal should be asserted and negated synchronously with
the SYSCLK signal.
7 .2.9.2 System Management Interrupt (SMl)-lnput
The system management interrupt (SMI) signal is input only. Following are the state
meaning and timing comments for the SMI signal.
State Meaning
Timing Comments
Asserted-The 604 initiates a system management interrupt
operation if the MSR[EE] is set; otherwise, the 604 ignores the
interrupt condition. The system must hold the SMI signal active until
the interrupt is taken.
Negated-Indicates that normal operation should proceed. See
Section 8.8.1, "External Interrupts."
Assertion-May occur at any time and may be asserted
asynchronously to the input clocks. The SMI input is level-sensitive.
Negation-Should not occur until interrupt is taken.
If deterministic cycle sequencing is required (for example, in multiple processor systems
operating in lock step), the SMI signal should be asserted and negated synchronously with
the SYSCLK signal.
7 .2.9.3 Machine Check Interrupt (MCP)-lnput
The machine check interrupt (MCP) signal is input only on the 604. Following are the state
meaning and timing comments for the MCP signal.
Chapter 7. Signal Descriptions
7-25