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LPCXpresso board LPC812  periph_uart example

Question asked by walt_lpc on Mar 22, 2017
Latest reply on Mar 22, 2017 by soledad

Hello, I am able to get the  periph_uart example to run, the leds blink, however the board is not outputting anything

on the serial port.


Things done:

Soldered a header into J7, and wired a USB to serial cable (one I have used on a cubieboard)

Confirmed the serial cable is working by tying Tx and Rx together

Black wire from usb cable to board ground

White wire from usb cable to LPC812 PIO0_0, Tx

Green wire from usb cable to LPC812 PIO0_4, Rx

Set the baud rate to 115200 in both Windows device manager, and putty terminal

I have not made any changes to the example project. Project is from LPSOpen.

LPCXpresso v8.2.2 [Build 650] [2016-09-09]


I thought maybe it was not possible to use the board's uart while in debug mode, so I built and tried a release version,

but had the same negative result. Any thoughts would be appreciated. Thanks!


... Two minutes after posting this I swapped Rx and Tx connections and it worked. I had hesitated to try this because

I was sure the wiring was ok, same as on cubieboard, and I was afraid of damaging the board. However, after checking

there pdf schematic, there are are 220 ohm resistors in series with the pins so I went ahead and swapped the wires.