I'm using the FRDM-K66F board and running the freertos_uart demo project. It works well enough through UART0, but this is carried through the USB debug connection and I need to look at the signal on the wire. I changed the demo project to use UART1 instead by the following steps:
1. Connect pins A9 and A11 to UART1 TX and RX by updating pin_mux.c
2. Change the DEMO_UART* symbols to refer to UART1 instead of UART0
3. Connect J1 pin 4 to pin 2 on the DE9 serial connector.
4. Connect J1 pin 2 to pin 3 on the serial connector.
5. Connect J3 pin 12 to pin 5 on the serial connector.
I can see that pin 2 on the serial connector is where I want to transmit because my script that watches the port picks up the noise when I disconnect and reconnect that wire. I've stepped through the code and see that the UART_WriteNonBlocking function is entered and eight characters are written to the D register on each pass until the last one which only has seven. So it seems we've done the right thing, but nothing is seen on the other end. I can see also that the UART1 driver IRQ handler is invoked.. This really looks like a pin issue. When I get to the receive part of the demo, the software always ends up terminating on a timeout on the event group wait.
Any experience with this out there?