RAK 4260 when Pin PA09 is activated as ADC the firmware goes wrong

Currently, I am working with the RAK 4260 and when I configure the PA09 pin (ADC_POSITIVE_INPUT_PIN17) as ADC, the firmware works for a while then it gives me an error in sending data, I have already tried on two modules and the same thing happens to me.
I have gone through the schematic diagrams in the available documentation and apparently that pin is available, and I would like to know why this failure occurs?

Hello Daniel,

Without knowing what your custom firmware is doing, it is impossible to tell why it stops working after some time. As you already discovered, PA09 is available and is not connected to anything else.

You say gives me an error in sending data. What error is this. And how are you sending data? Are you using LoRa P2P or LoRaWAN?

  • what region
  • what data rate
  • how big is your payload
  • is ADR enabled or disabled
  • how frequently are you sending data

I am using the module to send temperature data through LORAWAN, after sending the data the device goes into deep sleep.

When I tried using the PA09 pin I note that the device made several attempts to send data, and sometimes it again made a join request.

I have this configuration:

  • EU868
  • data rate is adaptive
  • the size of my payload is 16 Bytes
  • ADR is enabled
  • Data sending frequency = 2 min

I have looked in the firmware if that pin was defined somewhere, but it is not the case, in the Microchip firmware if it is defined to control the TCXO chip. But in this module it is PB03.

Hi Daniel,
I found this bug too some time ago and wasted many days trying to track it down. Afraid I gave up in the end and abandoned use of PA09 for analog input. You can find a broader discussion of 4260 quirks at: LoRa Node project

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Hi Steve,

I am using your firmware version, I have been looking for a solution to that bug for a while, but I have not achieved anything, it is best not to use the pin as ADC, in the same way it would be interesting if an explanation was given by RAK.