The UART will "drive" its TXD pin "up" during a "1-bit", a "stop-bit", and no
transmission. It will "drive" its TXD pin "down" during a "0-bit", "start bit",
and "break".
There is no internal pull-up. You can add an external pull-up but I do not see a
reason to do that. It is driven up and down.
--- In m..., "merapcb" wrote:
> Is there an internal pull-up on the UART Tx (both of
them) of the 1612? I did search the datasheet and found that only JTAG has
internal pull-ups. Need to decide if I need an external pull-up resistor for the
UTXD0/UTXD1 lines.
>
> Thanks
>
