xilinx 的mb-gcc编译器中printf问题
想使用printf函数，但是用xilinx公司自己的mb-gcc（针对microblaze）编译含有printf的函数时报一下错误：
write.c:36: undefined reference to 'outbyte'"/"read.c:35: undefined reference to 'inbyte'"
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有个帖子说：
This error occurs when the C-code contains "printf-" statements and a peripheral has not been defined as "std_out" and "std_in". To work around this problem, use one of the following solutions: 
Remove the "printf-" statement. 

or 

Define peripheral as Standard-out and Standard-in. 
This can be done by using the Software Platform Settings dialog box.
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我理解的就是说（第二种方法）把标准输入输出设置为外设，但是不清楚该怎么做，有高手了解相关东西么？



------解决方案--------------------
This can be done by using the Software Platform Settings dialog box
------解决方案--------------------
就是menuconfig选项里设置，或者查找平台下的kconfig