LPC81XM_13 datasheet(16/71 Pages) NXP

16 / 71 page

LPC81xM

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Product data sheet

Rev. 3 — 29 July 2013

16 of 71

NXP Semiconductors

LPC81xM

32-bit ARM Cortex-M0+ microcontroller

8.9 Switch Matrix (SWM)

The switch matrix controls the function of each digital or mixed analog/digital pin in a

highly flexible way by allowing to connect many functions like the USART, SPI, SCT, and

I2C functions to any pin that is not power or ground. These functions are called movable

functions and are listed in Table 5.

Functions that need specialized pads like the oscillator pins XTALIN and XTALOUT can

be enabled or disabled through the switch matrix. These functions are called fixed-pin

functions and cannot move to other pins. The fixed-pin functions are listed in Table 4. If a

fixed-pin function is disabled, any other movable function can be assigned to this pin.

8.10 Fast General-Purpose parallel I/O (GPIO)

Device pins that are not connected to a specific peripheral function are controlled by the

GPIO registers. Pins may be dynamically configured as inputs or outputs. Multiple outputs

can be set or cleared in one write operation.

LPC81xM use accelerated GPIO functions:

• GPIO registers are located on the ARM Cortex M0+ IO bus for fastest possible

single-cycle I/O timing, allowing GPIO toggling with rates of up to 15 MHz.

Fig 7.

Standard I/O pad configuration

LPC81XM Datasheet(PDF) 16 Page - NXP Semiconductors