This is new to a serial port some comments: polling mode will receive function in the while loop, each loop active asked and determine whether the data reception, CPU receives more CPU resources, so generally receive data using a serial port interrupt way, raise the interrupt after a serial port receives the data, the CPU is interrupted, interrupt the current task to deal with the received data, personal understanding polling and interrupt the biggest difference is that the CPU active and passive request, if you have other understanding, welcome
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