Damn the serial port problem.

Bluetooth serial port out of the problem, only can not receive, the baby also do not know where the reason. Every time you lose a lost, down to the board found can not be used. And I don't know why. Silly don't pull a few look at the program, look for problems. Watch it for a week. Later, the laboratory students with a multimeter!! The problem with the test is hardware. Multimeter in the baby here is to do experiments will think of something. Finally found that the original is because the serial module needs 3.3 Volts of electricity, and the supply voltage is 5 volts, so it is not good to make!!! Oh, my God. Baby silly not to pull a few see program Ah!! No matter how you look, you can't find a problem!!! Now the baby's Bluetooth can be a pair of three hair to send to ~ ~

Damn the serial port problem.