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© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
User manual Rev. 02 — 23 May 2005 30 of 133
Philips Semiconductors
UM10109
P89LPC932A1 User manual
4.4 Input-only configuration
The input port configuration is shown in Figure 11. It is a Schmitt-triggered input that also
has a glitch suppression circuit.
(Please refer to the P89LPC932A1 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 Figure 12
.
A push-pull port pin has a Schmitt-triggered input that also has a glitch suppression
circuit.
(Please refer to the P89LPC932A1 data sheet, Dynamic characteristics for glitch filter
specifications).
Fig 11. Input only.
002aaa916
input
data
PORT
PIN
glitch rejection
Fig 12. Push-pull output.
002aaa917
port latch
data
input
data
PORT
PIN
strong
glitch rejection
V
DD
P
N