MPC555CME Freescale Semiconductor, MPC555CME Datasheet - Page 335

• Manufacturer Part Number: MPC555CME
• Description: KIT EVALUATION FOR MPC555
• Manufacturer: Freescale Semiconductor
• Type: Microcontrollerr

Specifications of MPC555CME

• Contents: Module Board, Installation Guide, Power Supply, Cable, Software and more
• Processor To Be Evaluated: MPC555
• Data Bus Width: 32 bit
• Interface Type: RS-232
• For Use With/related Products: MPC555
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

9.5.8.2 Burst Inhibit
9.5.8.3 Transfer Error Acknowledge
9.5.8.4 Termination Signals Protocol
MPC555
USER’S MANUAL
A slave sends the BI signal to the master to indicate that the addressed device does
not have burst capability. If this signal is asserted, the master must transfer in multiple
cycles and increment the address for the slave to complete the burst transfer. For a
system that does not use the burst mode at all, this signal can be tied low permanently.
The TEA signal terminates a bus cycle under one or more bus error conditions. The
current bus cycle must be aborted. This signal overrides any other cycle termination
signals, such as transfer acknowledge.
The transfer protocol was defined to avoid electrical contention on lines that can be
driven by various sources. To this end, a slave must not drive signals associated with
the data transfer until the address phase is completed and it recognizes the address
as its own. The slave must disconnect from signals immediately after it has acknowl-
edged the cycle and no later than the termination of the next address phase cycle. This
means that the termination signals must be connected to power through a pull-up re-
sistor to avoid the situation in which a master samples an undefined value in any of
these signals when no real slave is addressed.
Refer to
/
MPC556
MCU
Figure 9-27 Termination Signals Protocol Basic Connection
Figure 9-27
and
Figure
EXTERNAL BUS INTERFACE
Rev. 15 October 2000
External Bus
9-28.
Slave 2
Acknowledge
Signals
MOTOROLA
Slave 1
9-39