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What is weak keeper circuit?

Latest Updated:03/23/2009


What is weak keeper circuit?


The weak keeper circuit is a circuit that fixes the input to the high level or the low level even when the I/O pins are not driven from the outside. In general, it is necessary for unused input pins to fix the input level by obtaining the pull-up resistors or the pull-down resistors outside; however, such external resistors are unnecessary by building this circuit into.

Nevertheless, the weak keeper circuit only maintains the previous state and it doesn't drive the high or low level. Please avoid the system configuration that the circuit which the microcomputer is externally installed expects the level that the weak keeper circuit of the microcomputer maintains.

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