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MPC7400 RISC Microprocessor Users Manual
Non-Protocol Signal Descriptions
State Meaning
AssertedIndicates that the MPC7400 should initiate a system
management interrupt if enabled in the MSR.
NegatedIndicates that the interrupt is not being requested.
Timing Comments
AssertionMay occur at any time asynchronously to SYSCLK; The
SMI input is level-activated.
NegationShould not occur until after the interrupt is taken.
8.5.3.3 Machine Check (MCP)Input
The machine check (MCP) signal is an input signal on the MPC7400. Following are the
state meaning and timing comments for the MCP signal.
State Meaning
AssertedIndicates that the MPC7400 should initiate a machine
check interrupt or enter the checkstop state as directed by the MSR.
NegatedIndicates that machine check handling is not being
requested.
Timing Comments
AssertionMay occur at any time asynchronously to SYSCLK; The
MCP input is falling-edge activated.
NegationMay occur any time after the minimum MCP pulse width
has been met; see the MPC7400 hardware speciTcations.
8.5.3.4 Reset Signals
There are two reset signals on the MPC7400hard reset (HRESET) and soft reset
(SRESET).
8.5.3.4.1 Soft Reset (SRESET)Input
Following are the state meaning and timing comments for the SRESET signal.
State Meaning
AssertedInitiates processing for a reset exception as described in
Section 4.6.1, òSystem Reset Exception (0x00100).ó
NegatedIndicates that normal operation should proceed. See
Section 9.7.3, òReset Inputs.ó
Timing Comments
AssertionMay occur at any time and may be asserted
asynchronously to the MPC7400 input clock. The SRESET input is
negative edge-sensitive.
NegationMay be negated two bus cycles after assertion.
This input has additional functionality in certain test modes.
8.5.3.4.2 Hard Reset (HRESET)Input
The hard reset (HRESET) signal must be used at power-on to reset properly the processor.
Following are the state meaning and timing comments for the HRESET signal.