I’m using an Arduino Due (clone) and want to run the UART3 (RX3/TX3) port in SPI mode - is that possible?
- I need only the TX3 pin to send out bytes at a given baud rate (without start and stop bits!), I don’t need the clock line.
- I can’t do bitbanging (CPU is busy) and all other SPI/UART ports are also already in use.
- The SAM3X8E comes in different packages: The 217-pin package has the UART3 with clock3 pin, so SPI-mode is supported. The Due uses the 144-pin package, with TX3/RX3 pins but the clock3 pin is not broken out.
I guess the actual chip inside the package is always the same, but does it “know” that the clock3 line is not connected to a pin?
So, can I just use the UART3 port in SPI mode (with all its limitations) or will the chip prevent that mode because it knows its pin configuration?
(Or will that even damage the chip?)