Chapter 2. Signal Descriptions and Clocking
2-27
Detailed Signal Descriptions
Timing Comments
Assertion—May occur at any time, asynchronous to any clock.
Negation—Must be asserted for at least 2 sys_logic_clk cycles. After
SRESET is negated, the processor vectors to the system reset vector.
2.2.5.3 Machine Check (MCP)—Output
The MCP signal is driven by the MPC8240 when a machine check error is generated by any
of the conditions described in Chapter 13, “Error Handling,” for generating the internal mcp
signal. The assertion of MCP depends upon whether the error handling registers of the
MPC8240 are set to report the specific error. Additionally, the programmable parameter
PICR1[MCP_EN] is used to enable or disable the assertion of MCP by the MPC8240 for
all error conditions. MCP is also used as a reset configuration input signal.
State Meaning
Asserted—Reflects the state of the internal mcp signal. Indicates that
a reportable error condition, as defined in Chapter 13, “Error
Handling,” has occurred. The current transaction may or may not be
aborted depending upon the software configuration. Assertion of
mcp causes the processor core to conditionally take a machine check
exception or enter the checkstop state based on the setting of the
MSR[ME] bit in the processor core.
Negated—There is no mcp being reported to the processor core.
Timing Comments
Assertion—mcp may be asserted to the processor core in any cycle,
so the same timing applies to MCP.
Negation—The MPC8240 holds mcp asserted until the processor
core has taken the exception. The MPC8240 decodes a machine
check acknowledge cycle by detecting processor reads from the two
possible machine check exception addresses at
0x0000_0200–0x0000_0207 and 0xFFF0_0200–0xFFF0_0207 and
then negates mcp. This timing also applies to MCP.
High impedance—If the PMCR2[SHARED_MCP] bit is set, the
MCP signal is placed in high impedance when there is no error to
report.
2.2.5.4 Nonmaskable Interrupt (NMI)—Input
The nonmaskable interrupt (NMI) signal is an input on the MPC8240. Following are the
state meaning and timing comments for the NMI input signal. See Chapter 13, “Error
Handling,” for more information.
State Meaning
Asserted—Indicates that the MPC8240 should signal a machine
check interrupt (mcp) to the processor core.
Negated—No NMI reported.
Содержание MPC8240
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Страница 454: ...12 14 MPC8240 Integrated Processor User s Manual Internal Arbitration ...
Страница 466: ...13 12 MPC8240 Integrated Processor User s Manual Exception Latencies ...
Страница 516: ...16 14 Watchpoint Trigger Applications ...
Страница 538: ...B 16 MPC8240 Integrated Processor User s Manual Setting the Endian Mode of Operation ...
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Страница 640: ...INDEX Index 16 MPC8240 Integrated Processor User s Manual ...