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PSoC™ 4

Anonymous
Not applicable

So if you configure a pin as Type: Analog and Drive mode: Resistive pull down (or Resistive pull up), the pin becomes a digital output pin? I'm finding that it simply follows the Initial drive state setting and can not be driven high or low even with a very low resistor value to ground or VCC.

I'm trying to avoid an external pull down resistor on an optical sensor by using the internal ones. Apparently not possible? Or what am I missing.

The datasheet says "If the Type is Analog, the default is High Impedance Analog. This is the only pin drive mode that can support purely Analog pins." but I assumed that was related to routing. Nothing else that I saw seems to indicate why this doesn't work.

I've tried a number of combinations, including checking both analog and digital input.

I'm new to the PSoC and would really appreciate a step by step direction or a simple "you can't do that". Thanks in advance.

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1 Solution
odissey1
Honored Contributor II

You need to check pin as analog AND digital output (resistive pull UP). To activate internal pull-up resistor (~5k) apply digital constant "1" to the pin's digital input. Demo project attached. Needles to mention that PSoC power supply has to be well filtered - all Vdd noise goes directly into detector sampling input.

/odissey1

AnalogPullUp_01a.png

AnalogPullUp_01a_pin.png

View solution in original post

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1 Reply
odissey1
Honored Contributor II

You need to check pin as analog AND digital output (resistive pull UP). To activate internal pull-up resistor (~5k) apply digital constant "1" to the pin's digital input. Demo project attached. Needles to mention that PSoC power supply has to be well filtered - all Vdd noise goes directly into detector sampling input.

/odissey1

AnalogPullUp_01a.png

AnalogPullUp_01a_pin.png

View solution in original post

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