Calculadora de Temporización SPI
Calcula parámetros de temporización del bus SPI: frecuencia de reloj, modos CPOL/CPHA y tiempos de setup.
Fórmula
t_bit = 1/f_CLK; τ = R_drive·C_trace; f_max = 1/(4.4τ)
Cómo Funciona
Serial Peripheral Interface (SPI) is a synchronous serial communication protocol used in embedded systems for short-distance communication between microcontrollers and peripheral devices. The protocol operates using a master-slave configuration with separate lines for data transmission (MOSI and MISO), a serial clock (SCLK), and a slave select (SS) line. SPI timing is critical for ensuring reliable data transfer, involving parameters like clock frequency, data transfer rate, and signal timing characteristics.
Ejemplo Resuelto
Consider a system with a master device operating at 10 MHz clock frequency. If the desired data transfer is 8-bit words, and the minimum clock pulse width is 50 nanoseconds, the calculation would proceed as follows: 1) Calculate maximum data transfer rate: 10 MHz = 10,000,000 transfers/second 2) Calculate minimum pulse duration: 50 ns per clock cycle 3) Verify setup and hold times meet device specifications 4) Determine total transfer time per 8-bit word: approximately 0.8 microseconds
Consejos Prácticos
- ✓Always verify timing specifications for both master and slave devices
- ✓Use pull-up/pull-down resistors to ensure stable signal levels
- ✓Consider signal integrity and minimize trace lengths
- ✓Choose appropriate clock frequencies based on device capabilities
Errores Comunes
- ✗Incorrect clock polarity and phase configuration
- ✗Neglecting maximum frequency limitations of peripheral devices
- ✗Inadequate signal conditioning for high-speed communications
Preguntas Frecuentes
What is the maximum SPI clock speed?
Typically ranges from 1 MHz to 50 MHz, depending on specific device and circuit design
How many devices can be connected to an SPI bus?
Multiple slave devices can be connected, limited by the number of slave select lines
What are the key SPI timing parameters?
Clock frequency, data transfer rate, setup time, hold time, and propagation delay
Shop Components
Affiliate links — we may earn a commission at no cost to you.
Related Calculators
Comms
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
Comms
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.
Comms
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.
Comms
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
Comms
RS-485 Termination
Calculate RS-485 bus termination resistors, bias resistors, maximum baud rate for cable length, propagation delay, and bias current consumption
Comms
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.