Communications Calculators

UART Baud Rate

Calculate UART frame timing, throughput, and USART BRR register divisor from baud rate, data format, and MCU clock frequency. Identify baud rate error for reliable serial communication.

I2C Pull-Up

Calculate I2C pull-up resistor values for Standard (100 kHz), Fast (400 kHz), and Fast-Plus (1 MHz) modes. Derives minimum, maximum, and recommended resistance from supply voltage and bus capacitance per NXP UM10204.

SPI Timing

Calculate SPI bus timing parameters including bit period, frame time, maximum clock frequency limited by trace capacitance, and signal slew rate

CAN Bus Timing

Calculate CAN bus bit timing parameters including prescaler, time quanta, sync segment, propagation segment, and phase buffer segments for a given baud rate and sample point

USB Termination

Calculate USB bus termination resistor values, differential impedance, cable propagation delay, signal rise time, and eye opening for USB 2.0 and USB 3.0

RS-485 Termination

Calculate RS-485 bus termination resistors, bias resistors, maximum baud rate for cable length, propagation delay, and bias current consumption

I2S Timing

Calculate I2S bit clock (BCLK), word clock (LRCLK/WCLK), and data rate for audio interfaces at any sample rate, bit depth, and channel count.

LIN Bus Timing

Calculate LIN bus bit time, break field length, frame time, and maximum frame rate for automotive LIN network design.

Modbus Timing

Calculate Modbus RTU character time, 3.5-character inter-frame gap, total frame duration, and maximum frame rate.

Ethernet Cable

Calculate Ethernet cable attenuation, maximum cable length, and pass/fail for Cat5e, Cat6, Cat6a, and Cat8 at 100Mbps, 1Gbps, and 10Gbps.