Communication

With microcontrollers it is possible to control actuators, read the values of sensors and many other stuff, but always stays the need for connecting all kind of devices, which does not allow to communicate by sending simple digital signals. The reason may be: there are too many control signals needed to control the device or there is too much data to be sent. That is why there are many data interface standards developed for microcontrollers or for every kind of electronics. The standards are determining the electrical parameters of the signals and the rules of transmission of the signals (the protocol).

One simple example of a protocol is the Morse code, where the information is transmitted using peeps and pauses and varying their lengths. Digital data transmitting protocols are functioning similarly; in there the info is transmitted as bit values and depending on the interface also as modulated form. Different data transmitting interfaces with their protocols have been created according to the need but the data quantities have always grown and new methods have been constantly added. The situation in the data transmission between the electronics components is calmer. There are I²C, SPI and UART interfaces used already for a long time. More traditional intersystem transmission interfaces are RS-232, RS-485, LIN and CAN, but many microcontrollers are already produced with USB, Ethernet and wireless ZigBee interfaces. This chapter is focusing on the data transmitting by using RS-232 interface.