MPC563XM Reference Manual, Rev. 1
376
Freescale Semiconductor
Preliminary—Subject to Change Without Notice
Figure 13-41. Basic Flow Diagram of an External Master Write Cycle
receives address
drives data
stops driving data
receives data
address in
internal memory map
no
yes
asserts transfer acknowledge (TA)
other shared device
asserts transfer
acknowledge (TA)
asserts bus busy (BB) if no other master is driving
assert transfer start (TS)
drives address and attributes
External Master
EBI (SLAVE)
request bus (BR)
receives bus grant (BG)
External Arbitration? *
yes
no
negates BG if asserted
asserted from external arbiter**
Ext. master has priority?
no
yes
negates BR if no other requests
receives BB negated for 2 cycles
***
** External arbiter is the EBI unless a central arbiter device is used.
* This refers to whether the external master device is configured for external or internal arbitration.
*** Determined by the internal arbiter of the external master device.