User manual

GHI Electronics,LLC Embedded Master User Manual
Embedded Master Products
2.1.4 USB Device
This connector is connected to the internal USB device peripheral of Embedded Master
Module. USB device feature allows Embedded Master to become almost any USB
peripheral that can be connected to a PC. .NET Micro Framework 3.0 has the ability to
change what type of USB device you need to create.
2.1.5 USB Host
Embedded Master Module's USB Host connector. This connector supplies 5V to the
connected USB device through a 250mA resettable fuse. The LED next to the connector
is an indicator if 5V power is available or not.
2.1.6 RS232
COM2 of Embedded Master Module is connected to a header named “COM2” and also
connected to an RS232 level converter. The level converter can be disabled by placing
the jumper “DISABLE”. The level converter must be disabled if the user wishes to use
any of the 4 COM2 pins for any use besides COM2. Also, the level converter can be
disabled if the user needs to connect a level converter of another type (RS485, LIN,
direct TTL...etc.)
COM2 Header
Header Pin # Function
1 E31/P2.7 or P3.30 TFT rev./UART_RTS1
2 E32/P2.1/UART_RXD1
3 E34/P2.2 or P3.18/UART_CTS1
4 E37/P2.0/UART_TXD1
Note that UART1 is actually COM2 because COM numbers start from 1 but
UART numbers start from 0 on LPC2478.
RS232 pins can be configured as DTE or DCE devices. DCE cannot connect directly to
DCE and DTE cannot connect directly to DTE. Only direct DCE to DTE can be used. To
connect 2 nodes of same kind, we need a null modem which basically is a swapping in
signal wires where transmit on one end will go to receive on the other end.
The RS232 signals on connector X4 are wired for DTE side. This is same as PC and so
this connector cannot be directly connected to a PC. A null modem or a cable with built
in null modem is needed. On the other hand, if connecting a DCE device, such as serial
Bluetooth module or serial GPS device, no null modem is needed.
Rev. 2.06 TFT Page 14 of 102 www.ghielectronics.com