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UM10237_2
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 02 — 19 December 2008
194 of 792
NXP Semiconductors
UM10237
Chapter 10: LPC24XX General Purpose Input/Output (GPIO)
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Mask registers allow treating sets of port bits as a group, leaving other bits
unchanged.
–
All GPIO registers are byte and half-word addressable.
–
Entire port value can be written in one instruction.
•
Bit-level set and clear registers allow a single instruction set or clear of any number of
bits in one port.
•
Direction control of individual bits.
•
All I/O default to inputs after reset.
•
Backward compatibility with other earlier devices is maintained with legacy registers
appearing at the original addresses on the APB bus.
3.2 Interrupt generating digital ports
•
PORT0 and PORT2 provide an interrupt for each port pin.
•
Each port pin can be programmed to generate an interrupt on a rising edge, a falling
edge, or both.
•
Edge detection is asynchronous, so it may operate when clocks are not present, such
as during Power-down mode. With this feature, level triggered interrupts are not
needed.
•
Each enabled interrupt contributes to a Wakeup signal that can be used to bring the
part out of Power Down mode.
•
Registers provide a software view of pending rising edge interrupts, pending falling
edge interrupts, and overall pending GPIO interrupts.
•
GPIO0 and GPIO2 interrupts share the same VIC slot with the External Interrupt 3
event.
4.
Applications
•
General purpose I/O
•
Driving LEDs or other indicators
•
Controlling off-chip devices
•
Sensing digital inputs, detecting edges
•
Bringing the part out of Power Down mode