UM10346_1
© NXP B.V. 2009. All rights reserved.
User manual
Rev. 01 — 2 November 2009
32 of 132
NXP Semiconductors
UM10346
LPC980/982 User manual
4.4 Input-only configuration
The input port configuration is shown in
. It is a Schmitt-triggered input that also
has a glitch suppression circuit.
(Please refer to the P89LPC980/982
data sheet, Dynamic characteristics
for glitch filter
specifications).
4.5 Push-pull output configuration
The push-pull output configuration has the same pull-down structure as both the open
drain and the quasi-bidirectional output modes, but provides a continuous strong pull-up
when the port latch contains a logic 1. The push-pull mode may be used when more
source current is needed from a port output.
The push-pull port configuration is shown in
.
A push-pull port pin has a Schmitt-triggered input that also has a glitch suppression circuit.
(Please refer to the P89LPC980/982
data sheet, Dynamic characteristics
for glitch filter
specifications).
Fig 10. Open drain output
002aaa915
port latch
data
input
data
glitch rejection
port
pin
Fig 11. Input only
002aaa916
input
data
port
pin
glitch rejection