MPC555
/
MPC556
EXTERNAL BUS INTERFACE
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
9-17
and asserts or negates the BDIP signal. If the master does not intend to drive another
data beat following the current one, it negates BDIP to indicate to the slave that the
next data beat transfer is the last data of the burst write transfer.
BDIP has two basic timings: normal and late (see
and
late timing mode, assertion of BDIP is delayed by the number of wait states in the first
data beat. This implies that for zero-wait-state cycles, BDIP assertion time is identical
in normal and late modes. Cycles with late BDIP generation can occur only during cy-
cles for which the memory controller generates TA internally. Refer to
for more information.
In the MPC555
/ MPC556, no internal master initiates write bursts. The MPC555
/
MPC556 is designed to perform this kind of transaction in order to support an external
master that is using the memory controller services. Refer to
During the data phase of a burst read cycle, the master receives data from the ad-
dressed slave. If the master needs more than one data beat, it asserts BDIP. Upon
receiving the second-to-last data beat, the master negates BDIP. The slave stops driv-
ing new data after it receives the negation of the BDIP signal at the rising edge of the
clock.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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