Hardware Development Guide
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ME3630 mini-PCIE
ME3630 mini-PCIE
Figure 4–13 Module Serial Port & AP Application Processor
UART1_RX
UART1_TX
UART1_CTS
UART1_RTS
UART1_DTR
UART1_DSR
UART1_DCD
UART1_RI
TXD
RXD
RTS
CTS
DTR
DSR
DCD
RING
Module
Application
DCE
DTE
If it does not match the PWL of AP interface, it is recommended to add the PWL conversion circuit. Otherwise, it might cause
unstable com ports because the level is not matched or cause damage to the module because it is at high level for long time. The
connection of module UART port and standard RS-232-C interface can be through the chip like class 232. The design involves the
transformation of TTL level and EIA level. We recommend to use the chip of NLSX5014MUTAG. If using the 2-wire serial bus interface,
MAX3232 is recommended, and if using the 8-wire serial bus interface, SP3238 or MAX3238 is recommended. The connection mode
is as shown in Figure below.
Figure 4–14 The connection of UART and Standard RS-232-C interface
TTL-
RS232
level
translator
SP3238
MAX3238
Module
1.8V
-TTL
level
translator
NLSX5014MUTAG
UART1_DCD
UART1_DSR
UART1_TX
UART1_CTS
UART1_RX
UART1_RFR
UART1_DTR
UART1_RI
GND
RS232_DCD
RS232_DSR
RS232_TXD
RS232_CTS
RS232_RXD
RS232_RTS
RS232_DTR
RS232_RI
GND
1
2
3
4
5
6
7
8
9
User Board
Female DB9
Note:
UART1_RFR is equal to UART1_RTS.
If customer wants to connect a 3.3V application system, a level shifter should be used. The following figure shows the reference
design. The diode in this Figure is Schottky diode (forward voltage drop is 0.3V). If you select other diodes, please select one with
lower forward voltage drop to make sure UART_RXD is below the threshold when inputting low level.