XC2200 Derivatives
System Units (Vol. 1 of 2)
The External Bus Controller EBC
User’s Manual
9-30
V2.1, 2008-08
EBC_X8, V1.0d1
Figure 9-14 Regaining the Bus by the Arbitration Master
Note: The falling BREQ edge shows the last chance for BREQ to trigger the indicated
regain-sequence. Even if BREQ is activated earlier the regain-sequence is
initiated by HOLD going high. Please note that HOLD may also be deactivated
without the XC2200 requesting the bus.
9.3.8.3
Arbitration Slave Scheme
If the EBC is configured as arbitration slave it is by default not owner of the external bus
and has to request the bus first. As long as it has not finished all its queued requests and
the arbitration master is not requesting the bus the arbitration slave stays owner of the
bus. For the description of the signal handling of the handshake see
For the arbitration slave the hold acknowledge pin HLDA is configured as input.
MCT05386
HOLD
HLDA
BREQ
CSx, WRH
WR/WRL, RD
ADD, BHE
Not Active Driven
Pull Up
High Impedance
Latest Possible Change
No BREQ Request