mpc823rg Freescale Semiconductor, Inc, mpc823rg Datasheet - Page 1151

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

Serial Communication Performance
A.1 CHANNEL COMBINATIONS
When operating the multiple HDLC/transparent channel protocol, most of the processing
load falls on the communication processor module. Protocols other than the multiple HDLC
and Transparent protocol rely on the hardware support built into the serial channels.
Combining the serial communication controllers and the microcontroller allows you to attain
throughput rates of up to 8Mbps in HDLC and Transparent mode.
The multiple channel protocol does not rely on the serial communication controllers and
operates transparently when you perform serial-to-parallel conversion and vice versa. All bit
manipulation is performed in the microcontroller software or hardware, which causes the
communication processor module to have a heavier load when operating in multiple channel
mode. The heavier load occurs even if all time-slots are concatenated to one logical
channel.
The following equation and Table A-1 can be used as a guide for calculating the
communication processor module’s load. The CPM load estimation is not truly linear, so
there is a gray area near the maximum limit (defined as 1). To determine the exact load, you
must test your operations on target hardware. The CPM load (L) is approximated by the
following equation:
where:
Since the equation and table estimates the feasibility of an application used only by the
CPM, it is your responsibility to verify the application against other issues (pin multiplexing,
parameter RAM, or microcode availability). The Motorola website (www.motorola.com)
contains a spreadsheet that performs the calculation of the CPM load.
L
=
Di is the user-targeted data rate for the particular CPM controller or protocol.
Pi is the CPM performance factor for the particular CPM controller or protocol. See
Table A-1 for specific values.
f is the actual CPM system frequency in megahertz.
i
D
---- -
P
i
i
25
----- -
f
1
Freescale Semiconductor, Inc.
For More Information On This Product,
MPC823 REFERENCE MANUAL
Go to: www.freescale.com
MOTOROLA