D E M O 9 S 1 2 X D T 5 1 2
J U L Y 1 8 , 2 0 0 8
13
COM Connector
A standard 9-pin Dsub connector provides external connections for the SCI0 port. The Dsub
shell is connected to board ground through a ferrite bead. The ferrite bead provides noise
isolation on the RS-232 connection. The figure below details the DB9 connector.
Figure 6: COM Connector
1
6
TXD
2
7
RTS
RXD
3
8
CTS
4
9
NC
GND
5
Female DB9 connector that interfaces to the MCU internal SCI0 serial
port via the RS232 transceiver. It provides simple 2 wire asynchronous
serial communications without flow control. Flow control is provided at
test points on the board.
Pins 1, 4, and 6 are connected together.
LIN Communications
The DEMO9S12XDT512 applies the MC33661D Local Interconnect Interface (LIN) physical
layer (PHY) for use in developing automotive control applications. The MC33661D physical
layer interface (PHY) supports LIN bus functionality for input voltages b6V and +18V.
Only power applied to the PWR connector will enable the LIN bus. Two, 4-pin, Molex con-
nectors provide off-board connectivity. The figure below shows the pin-out of the LIN connec-
tor looking into the connector.
Figure 7: LIN Connector
LIN I/O
4
3
V
SUP
GND
2
1
GND
REF: Mating Connector, Molex P/N,
39-01-2040, Housing
39-00-0039, Socket
NOTE
: Board must be powered from the PWR connector with V
IN
b6V and +18V.
LIN_EN
The LIN_EN option header enables or disables the LIN driver on SCI1.
Figure 8. LIN_EN Option Header
LIN_EN
4
3
TX
Enable LIN TX
2
1
RX
Enable LIN RX
NOTE
: Board must be powered from the PWR connector with V
IN
b6V and 18V.
