SPI-to-I2C Bridge Device and GPIO Port Expander​​​​​

The Silicon Labs CP2120 compact SPI-to-I2C bridge and general purpose port expander device can be easily added to a system to solve interface compatibility problems and add more GPIO when required. The chip includes a 4-wire slave SPI bus, bridge control logic, a bidirectional I2C bus interface, and eight general-purpose input/output (I/O) pins. An SPI master communicates with other I2C devices by instructing the CP2120 to send and receive I2C data traffic using the simple command set. The CP2120 can act as a master-transmitter and a master-receiver on the I2C bus. All I2C timing, addressing and arbitration is handled by the CP2120.


  • 4-wire SPI bus operates at frequencies up to 1 MHz
  • Fully-functional I2C master transmit and receive operation
  • I2C data at frequencies configurable up to 400 kHz
  • 255 byte data receive and transmit buffers
  • Internal oscillator
  • 2.4 to 3.6 volt operation
  • Active LOW interrupt output
  • 5 volt tolerant I/O pins
  • 8 general-purpose I/O pins

Get Started with CP2120

CP2120 Evaluation Kit

Check out SPI-to-I2C fixed functionality demonstrated on the CP2120 evaluation kit. Jumpstart development today with the CP2120 Evaluation Kit.

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Product Matrix

Part Number Data Sheet Eval Kit Interface RAM Package Type Package Size (mm) Internal Oscillator
CP2120 (NRND)
CP2120EK SPI to I2C 512 QFN20 4x4 No
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