2-4
MPC561/MPC563 Reference Manual
MOTOROLA
Signal Summary
TEA
1I/O
TEA
Transfer Error Acknowledge. This signal indicates that a bus
error occurred in the current transaction. The
MPC561/MPC563 asserts this signal when the bus monitor
does not detect a bus cycle termination within 2040 clock
cycles. The assertion of TEA causes the termination of the
current bus cycle, regardless of the state of TA.
An external pull-up device is required to negate TEA quickly,
before a second error is detected. That is, the signal must be
pulled up within one clock cycle of the time it was
three-stated by the MPC561/MPC563.
OE
1O
OE
Output Enable. This output line is asserted when a read
access is initiated by the MPC561/MPC563 to an external
slave controlled by the memory controller’s GPCM.
RSTCONF / TEXP
1
IRSTCONF until
reset negates.
Reset Configuration. This input line is sampled by the
MPC561/MPC563 during the assertion of the HRESET
signal in order to sample the reset configuration. If the line is
asserted, the configuration mode is sampled from the
external data bus. When this line is negated, the
configuration mode adopted by the MPC561/MPC563 is
either the internal default or read from the internal Flash
(MPC563 only).
O
Timer Expired. This output line reflects the status of
PLPRCR[TEXPS] in the USIU. This bit indicates an expired
timer value.
BI / STS
1
I/O
Controlled by
RCW[DBGC].
Burst Inhibit. This bidirectional, active-low, three-state signal
indicates that the slave device addressed in the current burst
transaction is not able to support burst transfers. When the
MPC561/MPC563 drives out the signal for a specific
transaction, it asserts or negates BI according to the value
specified in the appropriate control registers. The signal is
negated after the end of the transaction and then is
immediately three-stated.
This is an active-low signal and needs an external pull-up
resistor to ensure proper operation and signal timing
specifications.
O
Special Transfer Start. This output signal is driven by the
MPC561/MPC563 to indicate the start of a transaction on the
external bus or signals the beginning of an internal
transaction in show cycle mode.
Table 2-1. MPC561/MPC563 Signal Descriptions (continued)
Signal Name
No. of
Signals
Type
Function after
Reset 1
Description