MPC555
/
MPC556
EXTERNAL BUS INTERFACE
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
9-46
Figure 9-33 Retry On Burst Cycle
If a burst access is acknowledged on its first beat with a normal TA but with the BI sig-
nal asserted, the following single-beat transfers initiated by the MPC555
/ MPC556 to
complete the 16-byte transfer recognizes the RETRY signal assertion as a transfer er-
ror acknowledge.
In the case in which a small port size causes the MPC555
/ MPC556 to break a bus
transaction into several small transactions, terminating any transaction with RETRY
CLKOUT
ADDR[0:31]
TS
BR
BG (output)
BB
Data
TA
RD/WR
BURST
TSIZ[0:1]
RETRY
ADDR
ADDR
Allow External Master
to Gain the Bus
BI
If Asserted Will
Cause Transfer Error
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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