SWM Connect an internal signal to a package pin

A pin is identified for the purpose of programming the switch matrix by its default GPIO port pin number.

Example: Connect function U0_RXD and U0_TXD to pins 10 and 14 on the SO20 package

The switch matrix connects all internal signals listed in the table of movable functions through the pin assignment registers to external pins on the package. External pins are identified by their default GPIO pin number PIO0_n. Follow these steps to connect an internal signal FUNC to an external pin. An example of a movable function is the UART transmit signal TXD:

  1. Find the function FUNC in the list of movable functions in SWM Movable functions (assign to pins PIO0_0 to PIO0_17 through switch matrix) or in the data sheet.
  2. Use the LPC81x data sheet to decide which pin x on the LPC81x package to connect FUNC to.
  3. Use the pin description table to find the default GPIO function PIO0_n assigned to package pin x. m is the pin number.
  4. Locate the pin assignment register for the function FUNC in the switch matrix register description.
  5. Disable any special functions on pin PIO0_n in the PINENABLE0 register.
  6. Program the pin number n into the bits assigned to FUNC.

FUNC is now connected to pin x on the package.