MOTOROLA
Chapter 2. Signal Descriptions
2-17
Negated—Indicates that no bus error has been detected.
Assertion—Occurs during the data tenure in which the bus error is
detected.
Negation—Occurs one clock after assertion.
Timing Comments
2.2.2.16 Transfer Start (TS)
The transfer start (TS) signal is both an input and an output signal on the MPC106.
2.2.2.16.1 Transfer Start (TS)—Output
Following are the state meaning and timing comments for the TS output signal.
State Meaning
Asserted—Indicates that the MPC106 has started a bus transaction,
and that the address and transfer attribute signals are valid. Note that
the MPC106 only initiates a transaction to broadcast the address of a
PCI access to memory for snooping purposes.
Negated—Has no special meaning.
Timing Comments
Assertion—Occurs two clock cycles after BG
n
is negated and the
address bus is idle.
Negation—Occurs one clock cycle after assertion.
High-impedance—Occurs one clock cycle after the assertion of
AACK.
2.2.2.16.2 Transfer Start (TS)—Input
Following are the state meaning and timing comments for the TS input signal.
State Meaning
Asserted—Indicates that a 60x bus master has begun a bus
transaction, and that the address and transfer attribute signals are
valid.
Negated—Has no special meaning.
Timing Comments
Assertion—May occur one clock cycle after BG
n
is asserted.
Negation— Occurs one clock cycle after assertion.
2.2.2.17 Transfer Size (TSIZ[0–2])
The transfer size (TSIZ[0–2]) signals consist of three input and output signals on the
MPC106.
2.2.2.17.1 Transfer Size (TSIZ[0–2])—Output
Following are the state meaning and timing comments for TSIZ[0–2] as output signals.
Note that all MPC106-generated snoop operations are eight-word bursts; therefore
TSIZ[0–2] are always 0b010 for snoop operations.
State Meaning
Asserted/Negated—In conjunction with the transfer burst (TBST)
signal, TSIZ[0–2] specify the data transfer size for the 60x bus