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NXP Semiconductors
UMxxxxx
Install Guide
All information provided in this document is subject to legal disclaimers.
Preliminary 1
— September 6, 2013
© NXP B.V. 2013. All rights reserved.
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Fig 6.5 Input ramp (yellow trace), Red LED drive (green trace)
6.2.2 Push Switches
Each channel has a push switch (S01 through S71) that connects the appropriate IO pin to ground when
pressed. Series resistors (R01 through R71) limit the current, in the event that the IO pin is being driven high
(by the connected GPIO device) when the push switch is closed. Each input is biased to VC (one-half the supply
voltage), in the event that the IO pin is left open. This extinguishes both the Green and Red LEDs of that
channel, preventing false readings. See figure 6.6.
Содержание OM13260
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