Arduino library and hardware files for the SX1509 IO Expander Breakout board.
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SparkFun 16 Output I/O Expander Breakout - SX1509

SX1509 16 Output I/O Expander Breakout
SX1509 16 Output I/O Expander Breakout (BOB-13601)

The SX1509 16 Output I/O Expander Breakout Board makes it easy to prototype using the SX1509 so you can add more I/O onto your Arduino or I/O limited controller. It can leverage your I2C interface for 16 extra channels of GPIO and contains a fully programmable LED driver and a keypad scanning engine which enables continuous keypad monitoring of up to 64 keys. Since the I/O banks can operate between 1.2V and 3.6V (5.5V tolerant) independent of both the core and each other, this device can also work as a level-shifter.

Features include:

  • 16 channels of bi-directional I/O - Pull-up/down resistors, push/pull or open-drain outputs, programmable polarity.
  • 5.5V tolerant I/O's (1.2-3.6V operating voltage)
  • LED Driver: PWM and blink control on all I/O's, breathe capability on a select few.
  • Level shifting I/O's: Independent I/O rails (VCC1, VCC2) allow for up/down level shifting.
  • Keypad scanning engine: Supports up to 64 keys (in an 8x8 matrix configuration).

Repository Contents

  • /Hardware - Eagle design files (.brd, .sch)
  • /Libraries - Libraries for use with the
  • /Production - Production panel files (.brd)


Product Versions

  • BOB-13601 - SX1509 16 I/O Breakout Board (v20)
  • BOB-11502- (Retired) SX1509 16 I/O I2C port expander (v10)

License Information

This product is open source!

The hardware is released under Creative Commons ShareAlike 4.0 International.

The code is beerware; if you see me (or any other SparkFun employee) at the local, and you've found our code helpful, please buy us a round!

Please use, reuse, and modify these files as you see fit. Please maintain attribution to SparkFun Electronics and release anything derivative under the same license.

Distributed as-is; no warranty is given.

  • Your friends at SparkFun.