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PIC microcontroller communication protocol
When people are lost in the wild at night, they might only have a single flashlight. If a helicopter passes overhead, they can send an SOS signal by flashing the light in a specific pattern: three short flashes, followed by three long ones, and then three more short ones. This is the internationally recognized SOS distress signal, used to alert pilots or rescuers that help is needed. The pattern of light—short and long—is a form of communication protocol.
Similarly, a microcontroller can process communication protocols using electrical signals instead of light. Instead of light, it uses high and low voltage levels. For example, we can mimic the SOS signal by using a high level for "light" and a low level for "dark." A short pulse could be 10 milliseconds, while a long one could be 20 milliseconds. A microcontroller can output these pulses through its I/O pins, sending a sequence like high, high, high, low, low, low, high, high, high. Another microcontroller receiving this signal can interpret it based on pre-defined programming. It could trigger an alarm, turn on a device, or perform any action depending on what the signal represents.
This kind of communication is essentially a custom protocol, and as long as both devices agree on the format, it works. However, if every company or developer created their own unique protocol, it would lead to confusion and inefficiency. That’s why standardized protocols like USART, I2C, and SPI were developed. These ensure compatibility and simplify communication between different devices.
Let’s take a quick look at some key terms related to communication protocols:
**Serial Communication vs. Parallel Communication:**
Imagine you have eight apples and want to pass them to someone else. If you throw them one by one, that's serial communication. If you throw all eight at once, that's parallel communication. In the case of microcontrollers, it's not apples but bits being sent. Serial communication uses a single data line to send one bit at a time, while parallel communication uses multiple lines to send several bits simultaneously.
**Full-Duplex vs. Half-Duplex Communication:**
In half-duplex communication, only one party can send or receive at a time. Like a two-way conversation where only one person can speak at a time. Full-duplex allows both parties to send and receive information simultaneously, like a normal phone call where both people can talk and listen at the same time.
**Asynchronous vs. Synchronous Communication:**
Synchronous communication requires both devices to share a common clock signal so they can operate in sync. Asynchronous communication doesn’t rely on a shared clock, so the timing between the sender and receiver may vary. If two microcontrollers are communicating synchronously, they’re connected via a clock line. Without a clock line, they communicate asynchronously.
Understanding these concepts helps in designing efficient and reliable communication systems between microcontrollers and other electronic devices.