I'm designing a board based on KL25 low power uC with some I/O and four uart RS232 ports. The first three are provided from the peripheral of the uC, the fouth is another story. My idea is to use an IRQ pin to detect falling edge on the RX line of the uart and to detect the start bit, and a generic pin controlled by a TPM module for the TX line. Another timer will scan the signal on the RX line, 16 time faster than the baudrate of the serial line. I don' t need a fast uart, 9600bps is enough for my application.
Some of you have afforted a similar task? Or have a better idea than the one describer above? I'm also evaluating to add an I2C to UART driver bridge, but this
will increment component count of my board, and would be the worst solution.
Thanks in advance.