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楼主 |
发表于 2013-7-9 17:10:58
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huatong 发表于 2013-7-9 12:31
我没有看过该DataSheet,但先请看一下英文版的是不是这样.
Double Speed
Operation (U2X)
The transfer rate can be doubled by setting the U2X bit in UCSRA. Setting this bit only has effect
for the asynchronous operation. Set this bit to zero when using synchronous operation.
Setting this bit will reduce the divisor of the baud rate divider from 16 to 8, effectively doubling
the transfer rate for asynchronous communication. Note however that the Receiver will in this
case only use half the number of samples (reduced from 16 to 8) for data sampling and clock
recovery, and therefore a more accurate baud rate setting and system clock are required when
this mode is used. For the Transmitter, there are no downsides.
依旧没有讲寄存器具体该如何置位。
顺便问一个小白的问题:
Setting this bit的意思是不是置1(让我想起了51的SETB和CLR) |
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