DEMO9S12NE64 User’s Manual, Rev. 0.7
22 Freescale Semiconductor
Support Information
3.3 SCI Connector J53
Connector J53 is the SCI connector which is pinned out according to the DCE
format. Figure 3-2 and Table 3-2 give pin assignments and signal descriptions
for connector J53.
Figure 3-2 SCI Connector J53 Pin Assignments
GND
NC
NC
TXD
DTR_B
RX
D
NC
DCD_
B
DS
R_B
5432
6789
1
Table 3-2 SCI Connector J53 Signal Descriptions
Pin Label Signal
1, 4, 6 DCD_B, DTR_B,
DSR_B
Pins 1, 4 and 6 are the active-low Data Carrier Detect, Data Terminal Ready,
and Data Set Ready signals. These pins are connected together through zero
ohm resistors. To disconnect pin 1 from pin 4, remove R58. To disconnect pin
6 from pin 4, remove R57
2 TXD Pin 2 is the transmit data pin. It is connected to PS<1> of the MC9S12NE64
through a MAX3243 RS-232 Line Driver
3 RXD Pin 3 is the receive data pin. It is connected to PS<0> of the MC9S12NE64
through a MAX3243 RS-232 Line Driver
5 GND GROUND
7, 8, 9 NC Pins 7, 8 , and 9 can be used as active-low Request to Send (RTS_B), Clear to
Send (CTS_B), and Ring Indicator (RI_B) pins. These pins on J53 are not
connected on the DEMO9S12NE64. If these pins need to be utilized, they can
be accessed through the unpopulated one pin headers J28, J27, and J26
respectively
