User manual

LPC3250 Developer’s Kit v2 - User’s Guide
Page 29
Copyright 2013 © Embedded Artists AB
4.16 SP9: RS232 Interface
There is a RS232 interface with all modem signals on the board. The RS232 interface is available on a
9-pos male DSUB. The OEM Base Board is a DTE (Data Terminal Equipment). An external device can
be a DCE (Data Communications Equipment). For connecting DTE-to-DCE a straight-thru cable shall
be used. An external device can also be a DTE. For connecting DTE-to-DTE a null-modem cable shall
be used (also called a crossover cable). A PC is normally also a DTE so a null-modem cable shall be
used for communicating with a PC.
See picture below for locating relevant components on the board. The table below lists signal
connections. On the LPC3250 it is possible to connect UART #1 (just rx and tx) to the RS232
transceiver or UART#3 with all modem signals. Insert jumpers in all JP11 positions and place jumpers
in left position in JP12/JP13 to connect UART #3 (in full modem configuration) to the RS232 interface.
Remove all jumpers in JP11 and place jumpers in right position in JP12/JP13 to connect UART #1 (just
rx and tx) to the RS232 interface.
The interface component used (SP3243E) has built-in ESD protection.
Figure 15 – RS232 Interface
Signals
LPC3250
GPIO25_RXD
U1_RX, UART#1 is used
GPIO24_TXD
U1_TX, UART#1 is used
GPIO83_RTS_BD30
U3_HRTS / U2_RTS / GPO_23
GPIO92_DTR_BD21
U3_DTR / U2_TX
GPIO94_DCD_BD19
U3_DCD / GPI_05
GPIO93_DSR_BD20
U3_DSR / U2_RX
GPIO95_CTS_BD18
U3_CTS / U2_CTS / GPI_16
GPIO91_RI_BD22
U3_RI / GPI_28
GPIO97_TXD_BD16
U3_TX
GPIO96_RXD_BD17
U3_RX / P3.17
RS232 DSUB-9 Connector
J17
RS232 Modem Connection
JP11
RS232 Custom Connector
J18
RS232 Modem Connection
Upper: JP12
Lower: JP13
Left pos: 1-2, Right pos: 2-3