Pull-up resistors on GPIO 32/33 make them unusable?

[tanoshimi]

Hi!

According to the comment at https://www.kincony.com/forum/showthread...89#pid5689 , the GPIO pins 32/33 (normally described as "Temp/Humidity sensor") can also be used for WS2812 LED strips? And, presumeably, for any general purpose input-output then?

Unfortunately, it seems that they are attached to 4.7K pull-up resistors R23/R31 up to 3.3V? As far as I can tell, that makes them unusable for WS2812 data signal output, or in fact for many general purpose Input/Output uses

I hope I'm mistaken, in which case please can you provide an example of how to connect a WS2812B strip to an KC868-A6? (or, for that matter, an A4/A8/A6) - this would make the Kincony range significantly more appealing to me!

Thanks.

[admin]

these gpio can use for WS2812B LED strip, because WS2812B use by 5v power supply. you need to use a extend 5v dc power supply for LED strip. Not use by 3.3v.

[tanoshimi]

I am powering the LEDs with a separate 5V supply, with GND shared with the GND of the A6.
Then I'm using Pin 32 (or Pin 33, I have tried both) to the Data In of the first LED on the strip, but nothing lights.

I am using the FastLED library, which I have used in many projects in the past, and I have verified the strip works when connected to a bare ESP32, so I assume that it is the pullup resistor which is causing it to fail.

[tanoshimi]

these gpio can use for WS2812B LED strip, because WS2812B use by 5v power supply. you need to use a extend 5v dc power supply for LED strip. Not use by 3.3v.

Here's a photo of my wiring:

[admin]

wire is correct. i suggest you config by ESPHome firstly to test it.

[tanoshimi]

If I connect the DataIn of the strip to GPIO13 (from the serial connector) instead, the LED strips works as expected.

But I suspect that's because the pins on the serial connector are wired directly to the ESP32 GPIOs, instead of having the fixed pull-up resistor as DHT1/DHT2. So, I'm fairly sure that's the problem.

Please reconsider this design in the future! I'm going to have to desolder the pullup resistors to make those outputs useful, which is frustrating. (And, if I did want a pull-up resistor on GPIO32/33, I could always enable it in code anyway, using pinMode(32, INPUT_PULLUP)

 

[admin]

ok, thanks for your suggestion. now our new version of PCB all have two type of free GPIO. some have include pull-up resistor , some without pull-up resistor.

[tanoshimi]

Thankyou for the response (although I don't understand how you were ever able to get a WS2812B strip to work with the resistors in place, because I definitely can't!)

How will I know which boards are based on a new PCB? My board says version 1.3, and having an available output that can control LED strips is essential to me (it would also be nice to have the ability to connect an RFID sensor using an SPI interface, but that's a separate issue!)

[tanoshimi]

As expected, removing resistor R23 and creating a solder bridge across R24 means that GPIO32 now works perfectly to control the WS2812 strip. 
But it's ugly!

[admin]

about "new board", my means: F16,BM16M, F24,in future will release KC868-A6v3, will have gpio without pull up resistance.