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What is UART and RS232?
UART is a communications protocol, whilst RS232 defines the physical signal levels. That is, while UART has everything to do with logic and programming, it has nothing to do with the electronics per se. Whilst RS232 refers to the electronics and hardware needed for serial communications.
What is the purpose of a UART?
UART stands for Universal Asynchronous Receiver/Transmitter. It’s not a communication protocol like SPI and I2C, but a physical circuit in a microcontroller, or a stand-alone IC. A UART’s main purpose is to transmit and receive serial data. In UART communication, two UARTs communicate directly with each other.
What’s the difference between UART and serial protocols?
It means that the data is sent spread over time, most often one single bit after another. All the protocols you’re naming are serial protocols. UART, for Universal Asynchronous Receiver Transmitter, is one of the most used serial protocols. It’s almost as old as I am, and very simple. Most controllers have a hardware UART on board.
How many data lines does a UART use?
Most controllers have a hardware UART on board. It uses a single data line for transmitting and one for receiving data. Most often 8-bit data is transferred, as follows: 1 start bit (low level), 8 data bits and 1 or 2 stop bit (high level).
What’s the difference between USART, SPI, and USB?
A USART (Universal Asynchronous Synchronous Receiver Transmitter) is a device that can in addition do some kind (s) of synchronous transmission, hence the additional S. Which kind varies, you need to look it up in the data sheet. SPI, I²C, and USB are different (and in the case of USB very long) stories.
Which is better for long distance UART or RS-232?
For long distance communication (That doesn’t have to be hundreds of meters) the 5 V UART is not very reliable, that’s why it’s converted to a higher voltage, typically +12 V for a “0” and -12 V for a “1”. The data format remains the same. Then you have RS-232 (which you actually should call EIA-232, but nobody does.)