I am using the DA14580 WLCSP.
We planned to use the JTAG port for production programming, but I notice since that the Direct Test Mode and XTAL Trimming need the UART during production..
We are using external FLASH and all GPIO pins are currently being used. So I have a couple of questions for UART for when using Direct Test and Trimming only:
1.) Can P0_5 be ok for the UART Rx along with SPI FLASH? As the cost_prod_test file will be loaded into the RAM maybe this is ok as I see some reference designs use a test point for UART on P0_5 when using FLASH.
2.) As mentioned we don't have any further spare GPIO pins. For UART Tx which would normally be paired on P0_4, can this be combined with another pin function when in Direct Test Mode and XTAL Trimming? (i.e P0_4 that uses a resistor network for hardware ID selection or other pins).