LPUART Transmitter Active Soon as Enabled

[Mike_d]

Hi,

I trying to figure out why the TC status shows it as sending data the line after the transmitter is enabled and never goes idle.

Regards,

-Mike

[Mike_d · Accepted solution]

Found it.  I didn't have the PLL selected.

SIM_SOPT2 |= SIM_SOPT2_PLLFLLSEL(1);

[Mike_d]

So which is correct?  My problem is the TC bit is always 0.

[mjbcswitzerland]

Mike

The default for this flag is to be set, meaning that it will interrupt immediately when the UART is enabled if its interrupt mask is set.
It only goes to '0' while transmission is taking place and is set back to '1' (can generate interrupt) when the transmission terminates (idle-line again).
This is the same behavior as the TDRE flag apart from the fact that the TDRE goes high again when the data has been shifted out rather than after the last bit period has terminated.

Regards

Mark
Kinetis for professionals: http://www.utasker.com/kinetis.html