MPC5746R Hardware Design Guide, Rev. 1
Example Communication Peripheral connections
NXP Semiconductors40
10 Example Communication Peripheral connections
There are a wide range of peripheral pins available on MPC5746R. Many of these have fairly standard 
definitions for their use. This section provides example connections for some of the most commonly used 
communications peripherals, such as LIN, CAN, and RS-232 communication interfaces.
10.1 Example RS232 interface
The RS-232 (TIA/EIA-232-F) standard is a common interface once available on most computers. Adapters 
are available to allow the use of RS-232 peripherals though other interfaces, such as USB.
Figure 27 and Table 19 show the typical connections between the serial port of MPC5746R and the 
MAX3232-EP RS-232D transceiver from Texas Instruments. The transceiver operates from either a 3.3 V 
or a 5 V supply and includes two charge pumps to generate the output voltages that are required. This 
device contains two transmit drivers and two receivers. The charge pumps require four external capacitors.
Figure 27. Typical SCI to RS232 Circuit
NOTE
The commercial grade MAX3232 device is not rated for the full automotive 
temperature of –40 to +125
° C and is not intended for automotive 
applications. This device should not be used in a production module 
intended for automotive use. However, in many cases, the RS-232 interface 
is intended only as a development interface; therefore, the commercial 
device can be used for prototyping purposes. Texas Instruments offers a 
device option with an operating temperature range of –40 to +85
° C and an 
enhanced version of the device, MAX3232-EP, that is intended for 
aerospace, medical, and defense applications. This version is available with 
an operating temperature range of –55 to +125
° C.
1
The MPC5746R supports RS-232 
communication using the LinFLEX 
module configured to operate in UART 
mode.
LINnRX
1
LINnRX
1
LINnTX
1
LINnTX
1