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Initial startup configuration of I/Os | Cypress Semiconductor

Initial startup configuration of I/Os

Summary: 3 Replies, Latest post by Bob Marlowe on 29 Nov 2016 03:27 AM PST
Verified Answers: 0
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anands_2065436's picture
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2 posts

Hi,

 

I am using  CY8C4245 (Psoc4),and configured GPIOs as outputs and controlling them in application.

I am seeing the the IOs are going high during power up in my contoller. The Psoc3 and Psoc5 has the option of controlling the IOs during startup through nonvolatile latches (NVLs) but in Psoc4 seems to be diffucult ... ?

Is there any possibility to control (before init ) these during power up state..?

little help would be appreciated

Thanks,

Anand

 

user_1377889's picture
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9606 posts

Welcome in the forum, Anand.

There are 3 stages for PSoC4 GPIO pins during power-up:

  • Until the minimum voltage reached (1.8V) the outputs are undefined.
  • Outputs go High-Z until programmed during boot
  • Outputs follow the programming

To keep the pins to a defined state during the High-Z phase you will need some resistors to force the states to whatever you want.

 

Bob

anands_2065436's picture
User
2 posts

Thank You Bob,

But when checked the data sheet the reset option tab for GPIO pin is only applicable for PSoC 3 and PSoC5, and I am using PSoC4, Is there any other way to configure it. 

user_1377889's picture
User
9606 posts

No option for PSoC4, use resistors.

 

Bob

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