UART UCONn 设置 有点疑惑

Tx Interrupt Type [9] Interrupt request type.
0 = Pulse (Interrupt is requested as soon as the Tx buffer becomes
empty in Non-FIFO mode or reaches Tx FIFO Trigger Level in FIFO
mode.)
1 = Level (Interrupt is requested while Tx buffer is empty in Non-
FIFO mode or reaches Tx FIFO Trigger Level in FIFO mode.)


0
Rx Interrupt Type [8] Interrupt request type.
0 = Pulse (Interrupt is requested the instant Rx buffer receives the
data in Non-FIFO mode or reaches Rx FIFO Trigger Level in FIFO
mode.)
1 = Level (Interrupt is requested while Rx buffer is receiving data in
Non-FIFO mode or reaches Rx FIFO Trigger Level in FIFO mode.)


1.怎么感觉这里设置[0/1]都差不过啊？  有很大的区别吗？
2. 我们只对发送帧限制，好像不对接受帧进行限制？？ 为什么？

0是沿触发，1是电平触发哈