
MOTOROLA
Chapter 9. Error Handling
9-5
ErrDR1[3] (60x/PCI Cycle) and ErrDR2[7] (invalid error address) together with the 60x/
PCI error address register, the 60x bus error status register, and the PCI bus error status
register are used to provide additional information about the detected error. Once an error
is detected, the associated information is latched inside these registers until all the error
flags are cleared. Subsequent errors cannot set the status flags until the previous error’s flags
are cleared.
9.3.1 60x Processor Interface
The 60x processor interface of the MPC105 detects Flash ROM write errors and
unsupported 60x bus cycle errors. In either case, both ErrDR1[3] and ErrDR2[7] are
cleared, indicating that the error is due to a 60x bus transaction and the address in the 60x/
PCI error address register is valid. The MPC105 asserts either TEA or TA (depending on
the value of PICR1[TEA_EN]) to terminate the data tenure.
9.3.1.1 Flash ROM Write Error
The MPC105 allows single-byte writes to the ROM space when it is configured for Flash
ROM and PICR1[FLASH_WR_EN] is set. Otherwise, any 60x processor write transaction
to the ROM space results in a Flash ROM write error. Write transactions of more than one
data byte must be broken into a series of single-byte writes by software. When a Flash ROM
write error occurs, ErrDR2[0] is set.
9.3.1.2 Unsupported 60x Bus Error
When an unsupported 60x bus cycle error occurs, ErrDR1[1–0] is set to reflect the error
type. Unsupported 60x bus transactions include XATS-initiated transactions and
transactions with unsupported transfer attributes. Unsupported transfer attributes include
writes to the PCI/ISA INTACK address (0xBFFF_FFF
n
) using address map A, and illegal
and reserved transfer types defined in Table 4-1.
9.3.2 Memory Interface
The memory interface of the MPC105 detects parity errors on the data bus during memory
(DRAM or SDRAM transaction) read cycles or during L2 cache (SRAM) read cycles. The
MPC105 also detects errors with system memory transaction addresses that fall outside of
the physical memory boundaries.
If the memory read transaction was initiated by a PCI master, ErrDR1[3] is set; if the
memory read transaction was initiated by the 60x processor, ErrDR1[3] is cleared.
ErrDR2[7] is cleared to indicate that the error address in the 60x/PCI error address register
is valid. However, for L2 data parity errors, the MPC105 cannot provide the error address
and the corresponding bus status. Thus, ErrDR2[7] is set to indicate that the error address
in the 60x/PCI error address register is not valid.