NXP Semiconductors LPCXpresso54S018M User Manual

Contents

NXP Semiconductors UM11192User Manual for LPCXpresso54S018M Development BoardUM11192 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2019. All rights reserved.User manual Rev. 1.0 — 13th February 2019 21 of 347.1.4 Shield board current measurementTo use the on-board current measurement circuitry, any expansion board must match thefunctionality of the LPCXpresso54S018M. Refer to the board schematics for moreinformation.8. Board peripheral connections8.1 LPC54S018J4M USART ports and VCOM supportThe LPCXpresso54S018M board provides access to USART connections fromFlexcomm4 at the expansion connector J13.On LPCXpresso54S018M boards the USART from Flexcomm0 supports ISP UARTmode booting and is used by default for semi-hosting debug messages. This USART isconnected to a serial port on the Link2 Debug Probe, which provides a bridging functionto USB to a virtual com port (or “VCOM” port) on a host computer connected to thedebug link connector, J8. On revision C boards TXD and RXD from this USART are alsoavailable at header P4, for an external serial connection to be made. When using the P4connector, JP6 must be installed; note that when JP6 is installed the VCOM portfunctionality is disabled.The factory default CMSIS-DAP Link2 image includes UART bridge functionality (VCOMsupport), and this firmware is also available with the LPCScrypt utility, available athttp://www.nxp.com/lpcutilities. The J-Link firmware image available from LPCScrypt(version 1.9 onwards) or directly from SEGGER also has this feature (also see Section5.3.)8.1.1 P3 USART headerThe P4 header is designed to be used with an external serial to USB or other 3.3V serialdevice. P4 is only present on Revision C (and later) boards. Table 3 shows the pin outinformation. below. Note that the connections at P4 are made directly to theLPC54S018J4M device, so care should be taken to avoid ESD discharge and voltagesoutside the ratings of the device I/O pins.Table 3. P4 connectionsPin Function1 Ground2 RXD (from LPC54S018J4M)3 TXD (from LPC54S018J4M)8.2 USB portsThe LPCXpresso54S018M incorporates connectors for the two USB ports of theLPC54S018J4M device – a full speed (USB0) and a high speed port (USB1). Both ofthese USB ports support device and host functionality, but only one can be used as ahost port at any given time. Jumper settings must be set appropriately for host modeselection, as described in this section.