SYSCON PINTSEL addressOffset = 0x178

Each of these 8 registers selects one pin from all digital pins as the source of a pin interrupt or as the input to the pattern match engine. To select a pin for any of the eight pin interrupts or pattern match engine inputs, write the GPIO port pin number as 0 to 17 for pins PIO0_0 to PIO0_17 to the INTPIN bits. For example, setting INTPIN to 0x5 in PINTSEL0 selects pin PIO0_5 for pin interrupt 0.

To determine the GPIO port pin number on a given LPC81x package, see the pin description table in the data sheet.

Note: The GPIO port pin number serves to identify the pin to the PINTSEL register. Any digital input function, including GPIO, can be assigned to this pin through the switch matrix.

Each of the 8 pin interrupts must be enabled in the NVIC using interrupt slots # 24 to 31 (see NVIC Connection of interrupt sources to the NVIC).

To use the selected pins for pin interrupts or the pattern match engine, see Pin interrupt generator and pattern match engine (PINT).

Table 1. SYSCON registerName = PINTSEL[0:7] addressOffset = 0x178
Bit Symbol Description Reset value
5:0 INTPIN Pin number select for pin interrupt or pattern match engine input. (PIO0_0 to PIO0_17 correspond to numbers 0 to 17). 0
31:6 - Reserved -