Arduino Due - use of digital lines for serial comms ...

Good afternoon.

I am wondering how easy it may be to use some of the digital lines on the Arduino Due as serial output lines. I have a possible project which requires the sending text to quite a large number of LCD displays (possibly more than 10), and I thought that perhaps it could be done by using the digital lines as I realise that there are only 3 or 4 serial ports avialable by the usual methods.

Has anyone done this, and would anyone have any advice? I realise that it would involve stripping the textual characters down to their binaries, and sending the bits out via one of the digital pins at a rate acceptable to the target LCD serial in - almost writing one's own Serial Library, but I'm not completely au fait with how one might do this. I am reasonably experienced with the C flavour used for programming Arduino devices.

Thanks in advance for any comments.

Kenneth Spencer

Try looking at the softwareserial library (sorry, forgot to add the Link )

SoftwareSerial doesn’t work on the Due.

Oops.. Sorry

Try soft_uart

Maybe you need to rethink the approach. If you still have to design the lcd part as well, consider to make them intelligent with a microcontroller. You can basically hook up all lcd units to one serial port; this is known as a bus. For longer distances, you can use RS232 / RS422 / RS485.

Each LCD will have an address and your main micro will send a packet consisting of an address and the data over the bus. All lcd 'units' will receive the packet but only the one whose address matches the address in the packet will display it.

As lcds only require receiving, only one TX of the Due is needed, Rx can be left unused.

If distances are small (basically onboard), maybe SPI driven lcds can do the trick (not sure if you can get them off-the-shelf).

Just thinking (after the fact :frowning: ), which type of lcd are you actually talking about? Simple 16x2 types (or similar) or ...