mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 343

• Manufacturer Part Number: mpc823rg
• Description: Mpc823 Powerquicc Integrated Communications Processor For Portable Systems
• Manufacturer: Freescale Semiconductor, Inc

13.4.9.4 PROTOCOL FOR TERMINATION SIGNALS. The transfer protocol was defined
to avoid electrical contention on signals that can be driven by various sources. To do that, 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 acknowledged the cycle and no later than the termination of the next
address phase cycle. This indicates that the termination signals must be connected to power
through a pull-up resistor to avoid a situation in which a master samples an undefined value
in any of these signals when no real slave is addressed. See Figure 13-24 and
Figure 13-25 for more information.
Figure 13-24. Termination Signals Protocol Basic Connection
CLKOUT
RD/WR
TSIZ[0:1]
TS
DATA
TA,BI,TEA
A[6:31]
Figure 13-25. Termination Signals Protocol Timing Diagram
MPC823
Freescale Semiconductor, Inc.
For More Information On This Product,
ACKNOWLEDGE
SLAVE 1
ALLOWED TO
MPC823 REFERENCE MANUAL
SIGNALS
SLAVE 1
DRIVE
Go to: www.freescale.com
ACKNOWLEDGE
TURNS OFF
NEGATES
SIGNALS
SLAVE 1
AND
EXTERNAL BUS
SLAVE 2
ACKNOWLEDGE
ALLOWED TO
SLAVE 2
SIGNALS
SLAVE 2
DRIVE
ACKNOWLEDGE/TERMINATION
SIGNALS (TA, TEA, BI)
ACKNOWLEDGE
TURNS OFF
NEGATES
SIGNALS
SLAVE 2
AND
SLAVE 1
External Bus Interface
13-37