
MOTOROLA
Chapter 2. Signal Descriptions
2-19
2.2.2.20 Extended Address Transfer Start (XATS)—Input
The XATS signal is an input on the MPC106. Following are the state meaning and timing
comments for the XATS signal.
State Meaning
Asserted—Indicates that the 60x has started a direct-store access
(using the extended transfer protocol). Since direct-store accesses
are not supported by the MPC106, the MPC106 automatically
asserts the TEA signal when XATS is asserted (provided TEA is
enabled). If TEA is disabled, the MPC106 terminates the direct-store
access by asserting TA; however, no data is altered for write
operations, and invalid data is returned on read operations.
Negated—Has no special meaning.
Assertion—May occur one clock cycle after BG
n
is asserted. The
XATS signal can only be asserted by a processor (that is, the
MPC106 cannot assert XATS).
Negation—Occurs one clock cycle after assertion.
Timing Comments
2.2.3 L2 Cache/Multiple Processor Interface Signals
The MPC106 provides support for either an internal L2 controller or an external L2
controller and/or multiple 60x processors.
The signals ADS/DALE/BRL2, BA1/BAA/BGL2, DOE/DBGL2, and HIT function
differently depending on whether the MPC106 is in the internal L2 controller or external
L2 controller mode.
The signals BA0/BR3, DCS/BG3, DIRTY_IN/BR1, DIRTY_OUT/BG1, DWE0/DBG2,
DWE1/DBG3, TOE/DBG1, TV/BR2, and TWE/BG2 function differently depending on
whether the MPC106 is in the internal L2 controller or multiple 60x processor mode.
Section 2.2.3.1, “Internal L2 Controller Signals,” describes the internal L2 controller
configuration for these signals; Section 2.2.3.2, “External L2 Controller Signals,” describes
the external L2 controller configuration for these signals; and Section 2.2.3.3, “Multiple
Processor Interface Signals,” describes the multiple processor configuration for these
signals.
2.2.3.1 Internal L2 Controller Signals
This section provides a brief description of the interface signals for the internal L2
controller. The internal L2 controller supports synchronous burst SRAMs, pipelined burst
SRAMs, and asynchronous SRAMs. Some of the signals perform different functions
depending on the SRAM configuration.