GPIO firmware controlled pull up or pull down resistors.

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Anonymous
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In the "Digital I/Os" section on page 13 of the CYUSB3014 datasheet there is a statement that the I/O pins can be configured via firmware to be tristated, weak pull up, or pull down.  Does the FX3 support configuring a GPIO pin as an input with a weak pull up?  If so, how would this be done in firmware?

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7 Replies
Anonymous
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The beta version of the SDK does not have APIs to support this. The release version will have support for this configuration.

   

Regards,

   

Anand

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Anonymous
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What is the state of the digital I/O's after hardware reset? Are they tristated or is the internal resistor enabled (pull-up or pull-down)? Thanks.

   

 

   

Regards

   

Silvio

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Hello Silvio,

The state of GPIOs will depend on the boot mode after the hardware reset. This is already documented in section 11 of the following Application note:

https://www.cypress.com/file/201991/download

Best Regards,
Jayakrishna
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Anonymous
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In addition I do not find in the datasheet the maximum output current high and low for GPIO pins. Please let me know.

   

Regards

   

Silvio

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Hello,

This is already documented in Table 9 of FX3 datasheet. The link to the datasheet is given below:

https://www.cypress.com/file/140296/download

Best Regards,
Jayakrishna
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JCL
Level 1
Level 1
5 sign-ins First reply posted First question asked

Hello,

I have the same question on setting programmatically Pull-up/Pull-down on IOs.
I can't find anything that explicitely does that in cyu3gpio.h.
Has that been added to the API in the end?

Second question, if I want to set a GPIO in tristate mode, do I understand correctly that I shall set:
- outValue to cyTrue
- driveLowEn to cyFalse
- driveHighEn to cyFalse

Thanks in advance,
JC

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JayakrishnaT_76
Moderator
Moderator
Moderator
First question asked 1000 replies posted 750 replies posted

Hello,

Please find my comments to your questions below:

1. You can make use of the API CyU3PGpioSetIoMode () to enable weak pull up or pull down on IOs. Please refer to FX3 API guide to understand more about this API.

2. Yes, your understanding is correct.

Best Regards,
Jayakrishna
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