The baud rate is a fundamental parameter in serial communication, including UART (Universal Asynchronous Receiver/Transmitter). It represents the number of signal changes or symbols that occur per second. In the context of UART, the baud rate typically defines the number of bits transmitted per second.
The baud rate is usually determined by dividing the system's clock frequency by a prescaler or divider value. A common formula for calculating the baud rate is:
Baud Rate = Clock Frequency / Divider Value
However, in practice, microcontrollers often use a fractional divider, allowing for finer tuning and achieving standard baud rates more accurately. The divider is often represented by a value that, when used in a specific register (like the UBRR register in AVR microcontrollers), determines the baud rate.
The accuracy of the baud rate is crucial for reliable communication. If the baud rates of the transmitting and receiving devices do not match within a certain tolerance, data corruption will occur. The allowed error percentage helps determine if a calculated baud rate is acceptable for a given clock frequency and divider. A common acceptable error is typically around 2% to 5%.
How this calculator works:
This calculator takes your system's Clock Frequency (Hz) and the intended Divider Value. It then calculates the resulting baud rate. It also allows you to specify an Allowed Error (%). This helps you check if the calculated baud rate is within acceptable limits for standard serial communication.
Note: The exact implementation of the divider and baud rate generation can vary between microcontroller families. This calculator provides a general understanding based on common principles.