
MOTOROLA
Chapter 9. Error Handling
9-3
9.2.2.1 Machine Check (MCP)
The MPC105 asserts MCP to signal to the 60x processor that a nonrecoverable error has
occurred during system operation. The assertion of MCP depends upon whether the error
handling registers of the MPC105 are set to report the specific error.
Assertion of MCP causes the 60x processor to conditionally take a machine check
exception or enter the checkstop state based on the setting of the MSR[ME] in the 60x
processor. The programmable parameter PICR1[MCP_EN] is used to enable or disable the
assertion of MCP by the MPC105.
The MCP signal may be asserted on any cycle. The current transaction may or may not be
aborted depending upon the software configuration.
The MPC105 holds MCP asserted until the 60x processor has taken the exception. The
MPC105 decodes an interrupt acknowledge cycle by detecting 60x processor reads from
the two possible machine check exception addresses at 0x0000_0200 and 0xFFF0_0200.
9.2.2.2 Transfer Error Acknowledge (TEA)
The MPC105 asserts TEA to signal to the 60x processor that a nonrecoverable error has
occurred during data transfer on the 60x processor data bus. The assertion of TEA depends
upon whether the error handling registers of the MPC105 are set to report the specific error.
The assertion of TEA causes the 60x processor to conditionally take a machine check
exception or enter the checkstop state based on the setting of MSR[ME] in the 60x
processor. Note that the assertion of TEA does not prevent corrupt data from being written
into the cache or GPRs of the 60x processor.
The TEA signal may be asserted on any cycle that DBB is asserted. The assertion of TEA
terminates the data tenure immediately, even if in the middle of a burst. The MPC105
asserts TEA for only one clock.
The programmable parameter PICR1[TEA_EN] is used to enable or disable the assertion
of TEA by the MPC105. If PICR1[TEA_EN] is programmed to disable the assertion of
TEA, and a 60x processor data transfer error occurs, then the MPC105 asserts TA the
appropriate number of times to complete the transaction, but the data is unpredictable.
9.2.3 PCI Bus Error Signals
The MPC105 uses three error signals to interact with the PCI bus—SERR, PERR, and
NMI.
9.2.3.1 System Error (SERR)
The SERR signal is used to report PCI address parity errors, PCI data parity errors on a
special-cycle command, target-abort, or any other errors where the result is potentially
catastrophic. The SERR signal is also asserted for master-abort, except if it happens for a
PCI configuration access or special-cycle transaction.