Send instruction 1 program, lower machine returns 1, send instruction 2, lower machine return content 2;
But at the moment is to send what, return what, ask why?

CodePudding user response:

Line 1: pick the wrong
2: hardware broken
Suggestion: use a serial port debug tool test first, then use their serial port test

CodePudding user response:

Under this kind of situation is a machine problem

CodePudding user response:

Use the same variable?

CodePudding user response:

A machine without work,

CodePudding user response:

Check the problem that a machine

CodePudding user response:

1. Used for COM port?
2. Whether the wrong station?
3. The presence of a machine?