Serial ports can only be controlled by one program at a time.

Questions:

1. Why we only need to change the visibility value into integers? But not X value and Y value?

1. I got an undefined result in the serial input to p5js lab, and I am sure that I chose the correct port name and I opened the p5 serial port, also I selected the port from the p5 serial port. But if I only opened the p5 serial port and did not select the specific port in it, it worked. Why does it happen?

Don't open the port from p5 Serial port, just leave it open

1. For lab 3, I also cannot use p5js to control the LED light

Introduction of serial

• the meaning of those voltage levels; is a high voltage 1 and a low voltage 0, or is the signal inverted so that a low voltage is a 1 and high voltage is 0?

• the voltage levels representing a 1 or a 0 bit

• the rate at which data is sent and read

• For the data transmission above, a high voltage indicates a bit value of 1, and a low voltage indicates a voltage of 0. This is known as true logic. Some serial protocols use inverted logic, meaning that a high voltage indicates a logic 0, and a low voltage indicates a logic 1.

• serial buffer: they can do other tasks while waiting for data to come in, and act on the data from the buffer after it comes in.