UM11029
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© NXP Semiconductors N.V. 2017. All rights reserved.
User manual
Rev. 1.0 — 16 June 2017
145 of 515
11.1 How to read this chapter
The IOCON block is identical for all LPC84x parts. Registers for pins that are not available
on a specific package are reserved.
11.2 Features
The following electrical properties are configurable for each pin:
•
Pull-up/pull-down resistor
•
Open-drain mode
•
Hysteresis
•
Digital glitch filter with programmable time constant
•
Analog mode (for a subset of pins, see the LPC84x data sheet)
One I2C supports Fast-mode Plus with 1 Mbit/s data rates on two true open-drain pins
and listen mode. Three I2Cs support data rates up to 400 kbit/s on standard digital pins.
11.3 Basic configuration
Enable the clock to the IOCON in the SYSAHBCLKCTRL register (
, bit 18).
Once the pins are configured, you can disable the IOCON clock to conserve power.
Remark:
If the open-drain pins PIO0_10 and PIO0_11 are not available on the package,
prevent the pins from internally floating as follows: Set bits 10 and 11 in the GPIO DIR0
register to 1 to enable the output driver and write 1 to bits 10 and 11 in the GPIO CLR0
register to drive the outputs LOW internally.
UM11029
Chapter 11: LPC84x I/O configuration (IOCON)
Rev. 1.0 — 16 June 2017
User manual
Table 196. Pinout summary
Package
Pins/configuration registers available
HVQFN33
PIO0_0 to PIO0_28
HVQFN48
PIO0_0 to PIO0_31; PIO1_0 to PIO1_9
LQFP48
PIO0_0 to PIO0_31; PIO1_0 to PIO1_9
LQFP64
PIO0_0 to PIO0_31; PIO1_0 to PIO1_21