250 kHz I2C, 12 MHz SPI I2C/SPI Interface Device—The NI USB‑8451 is a master interface for connecting to and communicating with inter-integrated circuit (I2C), System Management Bus (SMBus), and serial peripheral interface (SPI) devices. With plug‑and‑play USB connectivity, the USB‑8451 is a portable solution to communicate with consumer electronics and integrated circuits. It also includes eight general-purpose digital I/O lines for a variety of applications, such as configuring the address of I2C devices or toggling LEDs. The USB‑8451 can be physically located more closely to I2C/SPI devices than PCI interfaces, reducing I2C bus length and minimizing noise problems. Additionally, the interface provides +5 V and GND to power circuits with no external power supply.