Methods used to transmit data between Digital devices are described below, But before this you need to know ways of communication that are wireless and wired.
In this type of communication, you have to depend on cable or wire to do communication between devices.
For example, If you look around yourself, you will find that printer connected to the computer via cable, get information or instruction via cable, and print that information as per instruction transmit through the computer.
In this type of communication, communication occurs without wire or cable that is wirelessly.
There are certain modules you heard of like Bluetooth, Wi-Fi (Wireless Fidelity), GSM and more which transmit information using radio frequency waves up to fixed range.
METHODS USED TO TRANSMIT DATA BETWEEN DIGITAL DEVICES
To do communication or data exchange between two devices, suppose one is Arduino and other may be wireless module (GPS module, GSM module, Bluetooth etc.), RTC module, SD card or other Arduino/ Development board etc. and/or between PC (personal computer) and Arduino.
You have to follow certain rules and regulations that are known as communication protocols.
There are several communication protocols and each protocol can be categorized into the two categories that are serial and parallel communication.
In other words, serial communication means the exchange of data one by one (in bit) while in parallel communication exchange of multiple data (many bits) at the same time.
SERIAL COMMUNICATION TO TRANSMIT AND RECEIVE DATA
- To transfer data to a device located far away, use serial communication method.
- The data sent in this as one bit at a time
- It is an umbrella word for all that is “Time Division Multiplexed”, to use an expensive term. It means that the data is sent spread over time, most often one single bit after another.
Serial Communication Protocols are USART, UART, USB, SPI, I2C RS232 etc.
TTL is a logic level (0 – 5V) on which many protocols or interfaces work. But RS232 is a serial protocol and works on (10V, 12V, 15V)
PARALLEL COMMUNICATION TO TRANSMIT AND RECEIVE DATA
- Often 8 or more lines (wire conductors) are used in transferring data to a device that is only a few feet away.
- Parallel interfaces transfer multiple bits at the same time.
- They require buses of data-transmitting across eight, sixteen or more wires.
- Data is transferred in huge, crashing waves of 1’s and 0’s.
COMPARING SERIAL AND PARALLEL
Think of the two interfaces like two different roads one is a two-lane rural road and the other is an eight-lane road.
For instance 8 people can drive through the eight-lane road in time x, while for 8 people to cross the two-lane road needs more time than x obviously.
But a two-lane road serves its purpose well and is more cost effective than making an eight-lane road.
Similar to this, parallel communication is fast, easy to implement and straight forward but requires more I/O pins/lines of the microcontroller.
Suppose we have an Arduino UNO. It has 14 digital I/O pins, if we use 8 of them then we are left with limited numbers of pins. So, we often select Serial communication (which is also simple to use) over parallel communication, sacrificing potential speed for pins.