MPC555
/
MPC556
EXTERNAL BUS INTERFACE
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
9-49
Figure 9-35 Basic Flow of an External Master Write Access
and
describe read and write cycles from an ex-
ternal master accessing internal space in the MPC555
/ MPC556. Note that the mini-
External Master
Request Bus (BR)
Receives Bus Grant (BG) From Arbiter
Asserts Bus Busy (BB) if No Other Master is Driving
Assert Transfer Start (TS)
Drives Address and Attributes
Asserts Transfer Acknowledge (TA)
Address in Internal
Memory Map
No
Yes
Asserts CSx
If In Range
Memory
Controller
Drives Data
Receives Address
Receives Data
MPC555 /
MPC556
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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