www.national.com
4
AN
-1
7
1
0
9.0
Board components and Pin As-
signments
A summary of the configuration and selection jumpers is
provided in the tables that follow. Reference both the sche-
matic and PCB layout (included on the CD in the kit)
Table 1.
Major Components List
Device
Description
U1
National LMX9838 Serial Port Module - Refer-
ence the device datasheet.
U3
National LP3985 Low-Dropout Voltage Regula-
tor
U2
Maxim MAX3225 1 Mbps High Speed UART
Driver
Table 2
Connectors Summary
Connector
Description
Details
J7
Battery Connector
2mm pitch
Maximum input volt-
age is 6V
J6
DC jack
Same as above
J8
DP9 serial connec-
tor (male)
See Table 5
J5
External processor
interface
See Table 6
J4
Advance Audio
interface
See Table 7
Table 3
Jumper and Test Point Summary
Jumper /
Test Point
Description
Details
J1, J2 and
J3
Clock & UART set-
ting jumper
See Table 8
Table 4
Switch and LEDs
Switch/LED
Description
S1
Reset button
D1
Operation Status
D2
Data Traffic (TX/RX)
Table 5
J8 DP9 (male) Pin Assignments
Pin #
Signal name
Description
1
NC
No connection
2
RxD
Receive Data (input)
3
TxD
Transmit Data (output)
4
NC
No connection
5
GND
Ground
6
NC
No connection
7
RTS
Ready to send (output)
8
CTS
Clear to send (input)
9
NC
No connection
Table 6
J5 External Processor Interface
Pin #
Signal name
Description
1
POWER_D#
ON/OFF control of LMX9838
2
VCC
LDO output (3.3V)
3
GND
Ground
4
TXD
Transmit Data (output)
5
CTS#
Clear to send (input)
6
RXD
Receive Data (input)
7
RTS#
Ready to send (output)
8
VCC_CORE
_IN
1.8V voltage regulator input/out-
put
9
RESET#
Reset (input)
Table 7
J4
Advance Audio Interface
Pin # Signal name
Description
1
VCC
LDO output (3.3V)
2
SCLK
Advanced Audio Interface Clock
3
STD
Advanced Audio Interface
Transmit Data
4
SFS
Advanced Audio Interface Frame
Synchronization
5
SRD
Advanced Audio Interface
Receive Data
6
GND
Ground
Table 8
UART interface setting
J2
J3
J1
UART baud rate
Short
Short
Short
921600bps
Short
Open
Short
115200bps(default)
Open
Short
Short
9600bps
Open
Open
Short
NVS (Default 9600bps)
