大概知道为什么设置成0x80了,是不是这一位就是当skip用的,因为不可能出现128大小的buffer;而ARM的意思相当于舍弃当前数据,装载需要数据
If the SKIP bit is set to ‘1’, the just-received OUT packet
is not committed to the output FIFO for transfer to the
external logic; instead, the packet is ignored, its buffer is
immediately made available for the next OUT packet,
and the output FIFO (and external logic) never even
‘knows’ that it arrived.