LPC Link2 COM port

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LPC Link2 COM port

NXP Employee
NXP Employee
Content originally posted in LPCWare by dalzan on Tue May 17 15:45:50 MST 2016
I am a beginner with LPC/ARM.

When I connect LPC Link2 via USB to my computer and launch Debug there appear 2 "HID Standard Devices" / "CMSIS-DAP" and "LPC-SIO Port", and also "Ports (COM and LPT)" / "LPC-LinkII UCom Port (COM3)". Maybe also some others I haven't noticed..

Do I understand right the HID interface is used for JTAG/SWD debugger and the port COM3 is free to use ?
I see on the schematic diagram of Link2 that "Serial Expansion Interface" connector J3 contains pins UART2_RXD + UART2_TXD;
when I open this COM3 with TeraTerm or other UART terminal and enter some text, will it be transmitted to this UART2_TXD ?

I know I could test it myself, problem is with the 50mils fine pitch headers, not so easy to connect anything here quickly.
My plan is to interconnect Link2 (UART2 pins mentioned above) with NGX LPC-4330-Xplorer / connector J8 / pins 9,10 == U0_TXD+U0_RXD.
Then I could test application with UART output without a need for additional TTL->UART->USB converter.

Any comments appreciated.
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2 Replies

Contributor I

HS USB bandwidth and available SRAM was seen as too limiting; ports P2_0 and P2_1 were used as trace testmyspeed.onl port connections to the target via a  buffer. 

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NXP Employee
NXP Employee

The default firmware for the standalone LPC-Link2 uses the same port pins as the on-board version, which are P2_0 and P2_1. When LPC-Link2 was initially designed there was a long term goal to support parallel trace, which was never implement as HS USB bandwidth and available SRAM was seen as too limiting; ports P2_0 and P2_1 were used as trace port connections to the target via a buffer. 

It is possible to get a unidirectional VCOM port (from a target to the host PC via LPC-Link2) by connecting to pin 16 of the SWD/JTAG/ETM connector J8 at pin 16. Due to the buffer between the LPC4370 on LPC-Link2 (originally intended for trace data), it is not possible to get data in the other direction.

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