The iolinker chip functions as a dynamically configurable IO matrix. Its main functionality, besides IO extension, is to dynamically set up a matrix of GPIO connections, that allow direct pass-through of high-frequency signals. Circuits can thereby be configured and programmed on the fly. There are UART / SPI / I2C versions that allow for easy integration of up to 127 chips connected in parallel. Some versions also allow for PWM signal output.