IO output

cvargcal
Posts: 12
Joined: Sat Sep 08, 2018 2:06 pm

IO output

Postby cvargcal » Tue Nov 13, 2018 2:06 pm

Hi, this is my first time for work with SoC and freeRTOS.
I need set 3 IO to 0 Level just in void app(), why the micro take many time for put this IO to 0 once time turn on.

Take 2 to 3 sec for runing the software, this is bad cause I have conect one buzz to IO output, and to start is in level 1. after 2 sec go to 0 as I did in code.

How I do for this "config IO" be more faster even before to run the OS, as a normal micro?

tommeyers
Posts: 63
Joined: Tue Apr 17, 2018 1:51 pm
Location: Santiago, Dominican Republic

Re: IO output

Postby tommeyers » Tue Nov 13, 2018 2:21 pm

Is it floating high on start-up (probably). Meaning it is not set high but it has a value that makes it appear high.

In that case I think you can: use a pull-down on that line to make it low on power-up.

To see if it is floating high look at it on a 'scope.

Tom Meyers
IT Professional, Maker
Santiago, Dominican Republic

tommeyers
Posts: 63
Joined: Tue Apr 17, 2018 1:51 pm
Location: Santiago, Dominican Republic

Re: IO output

Postby tommeyers » Tue Nov 13, 2018 2:24 pm

Take a look at this: https://www.arduino.cc/en/Tutorial/DigitalPins

Yes, it applies beyond Arduino.

Tom Meyers
IT Professional, Maker
Santiago, Dominican Republic

cvargcal
Posts: 12
Joined: Sat Sep 08, 2018 2:06 pm

Re: IO output

Postby cvargcal » Tue Nov 13, 2018 3:29 pm

tommeyers wrote:
Tue Nov 13, 2018 2:24 pm
Take a look at this: https://www.arduino.cc/en/Tutorial/DigitalPins

Yes, it applies beyond Arduino.

Tom Meyers

Ohh I see... thanks you for answer... I only worked with microchip... so I need pullups mmmm
the ESP32 has internal pullup? the same problem I have with the UARTs, I have one module connect to RXpin and TXpin, and one PIN to mosfet for turn on/off the module... I see te module never off even if I turn off mosfet, the module take power since TX and RX pin
... do you know how fix this...?

tommeyers
Posts: 63
Joined: Tue Apr 17, 2018 1:51 pm
Location: Santiago, Dominican Republic

Re: IO output

Postby tommeyers » Tue Nov 13, 2018 9:04 pm

I believe that the internal pull-ups *can* be activated by code but I don't think by default are they activated.

In your case it sounded like high was what caused the sound generator because:!===> without a signal from the processor they "float" and to the sound driver they appear high. So, the solution I proposed was to pull them low with a resistor from the ping to ground. That way not floating high but at the same time able to be pulled high from the processor. And that assures that when you have power to the processor and no signal from the processor on the pin they will be low.

Do you have a 'scope?

Tom Meyers
IT Professional, Maker
Santiago, Dominican Republic

cvargcal
Posts: 12
Joined: Sat Sep 08, 2018 2:06 pm

Re: IO output

Postby cvargcal » Tue Nov 13, 2018 10:01 pm

tommeyers wrote:
Tue Nov 13, 2018 9:04 pm
I believe that the internal pull-ups *can* be activated by code but I don't think by default are they activated.

In your case it sounded like high was what caused the sound generator because:!===> without a signal from the processor they "float" and to the sound driver they appear high. So, the solution I proposed was to pull them low with a resistor from the ping to ground. That way not floating high but at the same time able to be pulled high from the processor. And that assures that when you have power to the processor and no signal from the processor on the pin they will be low.

Do you have a 'scope?

Tom Meyers
Yes I undertand... thanks you... No like many the idea... because that mean I need resistors for every IO that I used... I will find how active the pullup and pulldown... I belive this SOC has internal resistor as other micros.

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