I2C Pin description

The I2C pins are movable pin functions and are assigned to pins on the LPC81x packages through the switch matrix. You have two choices to connect the I2C pins:

  1. Connect to special I2C open-drain pins (PIO0_10 and PIO0_11).
  2. Connect to any other pin that can host a movable function.

When the I^ 2C function is connected to specialized I^ 2C pins, it supports the full I^ 2C-bus specification up to Fast Mode Plus (up to 1 MHz I^ 2C).

When the I^ 2C function is connected to standard pins that are set to open-drain mode, a functional I^ 2C-bus can be used in this way, but some aspects of the I^ 2C-bus specification may not be met. This can have an impact on the bus speed, noise filtering, and the capability of powering down the device without affecting the bus.

See SWM Connect an internal signal to a package pin to assign the I2C pins to any pin on the LPC81x package.

Table 1. I2C I2C-bus pin description
Function Type Pin Description SWM register Reference
I2C0_SCL I/O any; use pin PIO0_10 or PIO0_11 for compatibility with the full I2C-bus specification. I2C0 serial clock. PINASSIGN8 SWM registerName = PINASSIGN8 addressOffset = 0x020
I2C0_SDA I/O any; use pin PIO0_10 or PIO0_11 for compatibility with the full I2C-bus specification. I2C0 serial data. PINASSIGN7 SWM registerName = PINASSIGN7 addressOffset = 0x01C

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