7 years, 5 months ago.

Need another serial port

I'm working on a project using an mbed lpc1768 that requires 2 can connections and 3 serial ports, if i use 2 CAN connections then I'm left with only 2 serial ports. Can i use 2 other pins for my 3rd serial port.

Thanks

1 Answer

7 years, 5 months ago.

Yes it's possible. The pinout diagram doesn't list all of the possible pin combinations. If you look at the schematic and LPC1768 data there are a few ways to do it.

The pinout I've used is:

  • CAN1 Tx P10, Rx P9
  • CAN2 Tx P29, Rx P30
  • UART1 Tx P26, Rx P25
  • UART2 Tx P28, Rx P27
  • UART3 Tx P17, Rx P18

(Note: these are CPU UART numbers, the pinout diagram numbers them differently for some reason).

There are a few other ways you can pin it out to get all the ports, just take care that you don't try to use the same UART on two different sets of pins, it will run but not do what you want. The reason I did it that ways was that it then leaves P13 free to use as an SPI clock meaning you still have both SPI busses if you need them (I use one for an SD card and one for talking to other devices)

Accepted Answer

Thanks Andy thats exactly what i was looking for

posted by Derek H 11 Oct 2016