Nxp Semiconductors OM11043 数据表

LPC1769_68_67_66_65_64_63

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© NXP Semiconductors N.V. 2014. All rights reserved.

order to keep the noise coupled in via the PCB as small as possible. Also parasitics 
should stay as small as possible. Values of C

x1

 and C

x2

 should be chosen smaller 

accordingly to the increase in parasitics of the PCB layout. 

 shows the possible pin modes for standard I/O pins with analog input function:

Digital output driver: Open-drain mode enabled/disabled

Digital input: Pull-up enabled/disabled

Digital input: Pull-down enabled/disabled

Digital input: Repeater mode enabled/disabled

Analog input

The default configuration for standard I/O pins is input with pull-up enabled. The weak 
MOS devices provide a drive capability equivalent to pull-up and pull-down resistors.

 

PIN

V

DD

V

DD

ESD

V

SS

ESD

strong
pull-up

strong
pull-down

V

DD

weak
pull-up

weak
pull-down

open-drain enable

output enable

repeater mode

enable

pull-up enable

pull-down enable

data output

data input

analog input

select analog input

pin configured

as digital output

driver

pin configured

as digital input

pin configured

as analog input