
9-2
MPC105 PCIB/MC User's Manual
MOTOROLA
Note that for priority 1 through 4, the interrupt is the same. The machine check exception
and the priority are related to additional error information provided by the MPC105 (for
example, the address provided in the 60x/PCI error address register).
9.2 Interrupt And Error Signals
Although Chapter 2, “Signal Descriptions,” contains the signal definitions for the interrupt
and error signals, this section describes the interactions between system components when
an interrupt or error signal is asserted.
9.2.1 System Reset
The system reset interrupt is an asynchronous, nonmaskable interrupt that occurs at power-
on reset (POR) or when the hard reset (HRST) input signal is asserted.
When a system reset request is recognized (HRST or POR), the MPC105 aborts all current
internal and external transactions, tri-states all bidirectional I/O signals, ignores the input
signals (except for SYSCLK, and the configuration signals FNR/DWE0, RCS0, DL0,
XATS, and PLL0–PLL3), and drives most of the output signals to an inactive state. The
MPC105 then initializes its internal logic. For proper initialization, the assertion of HRST
must satisfy the minimum active pulse width. The minimum active pulse width and other
timing requirements for the MPC105 are given in the MPC105 Hardware Specifications.
During system reset, the latches dedicated to JTAG functions are not initialized. The IEEE
1149.1 standard prohibits the device reset from resetting the JTAG logic. The JTAG reset
(TRST) signal is used to reset the dedicated JTAG logic during POR.
9.2.2 60x Processor Bus Error Signals
The MPC105 provides two signals to the 60x processor bus for error reporting—MCP and
TEA.
Table 9-1. Externally-Generated Interrupt Priorities
Priority
Exception
Cause
Processor
Recoverability
0
System reset
HRST or power-on reset (POR)
Nonrecoverable in all
cases
1
Machine check
(MCP or TEA)
Memory select error or memory data read parity error
Nonrecoverable in most
cases
2
Machine check
(MCP)
Illegal transaction type or Flash ROM write error
Nonrecoverable in most
cases
3
Machine check
(MCP)
PCI address parity error (SERR), PCI data parity error
(PERR), PCI master-abort, received PCI target-abort
Nonrecoverable in most
cases
4
Machine check
(MCP)
NMI
Nonrecoverable in most
cases