Philips P89LPC907 用户手册

2003 Dec 8     

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The input port configuration is shown in Figure 4-3. It is a Schmitt-triggered input that also has a glitch suppression circuit (please 
refer to the P89LPC906/907/908 datasheet, AC Characteristics for glitch filter specifications)

The push-pull output configuration has the same pulldown structure as both the open drain and the quasi-bidirectional output 
modes, but provides a continuous strong pullup 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 4-4.

A push-pull port pin has a Schmitt-triggered input that also has a glitch suppression circuit (please refer to the P89LPC906/907/
908 datasheet, AC Characteristics for glitch filter specifications)

The P89LPC906/907/908 incorporates an analog comparator. In order to give the best analog performance and minimize power 
consumption, pins that are being used for analog functions must have both the digital outputs and digital inputs disabled.

Digital outputs are disabled by putting the port pins into the input-only mode as described in the Port Configurations section (see 
Table 4-2).

Digital inputs on Port 0 may be disabled through the use of the PT0AD register. On any reset, the PT0AD bits default to ’0’s to 
enable digital functions.

port
pin

input data

glitch rejection

strong

V

DD

input data

port latch data

port
pin

glitch rejection