[Bluetooth Low Energy] float64LittleEndian conversion fails to display valid data from BLE notifications

[mcitem]

Description

Below are my test Bluetooth data for 1.0 represented as both f64 and f32 in little-endian byte order.

This is the byte representation of 1.0_f64:

[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xF0, 0x3F]

This is the byte representation of 1.0_f32:

[0x00, 0x00, 0x80, 0x3F, 0x00, 0x00, 0x00, 0x00]

When testing with the following Phyphox experiment over Bluetooth,
I found that when using float64LittleEndian, and my device sends the notification
[0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xF0, 0x3F],
the CH1 display in the app keeps flickering between a dash “–” and “0.00”.

Initially, I suspected an issue with my Bluetooth device or byte order,
but after switching the conversion function to float32LittleEndian
and sending [0x00, 0x00, 0x80, 0x3F, 0x00, 0x00, 0x00, 0x00],
the display started working correctly.

I verified the data using the GattBrowser Android app,
so I believe my BLE device is working properly.
It seems likely that there’s an issue with the float64LittleEndian conversion,
but I’m not sure how to provide more diagnostic logs.

If needed, I can provide logcat output from Android Studio (ADB wireless debugging).

Android phyphox version(1.2.0)
file format(1.19)
Build:1020009

<phyphox xmlns="https://phyphox.org/xml" version="1.19">
  <title>F64_Test</title>
  <category>mcitem@github.com</category>
  <data-containers>
    <container>CH1</container>
  </data-containers>
  <input>
    <bluetooth mode="notification" rate="1">
      <output char="cddf1002-30f7-4671-8b43-5e40ba53514a" conversion="float32LittleEndian" offset="0">CH1</output>
    </bluetooth>
  </input>
  <views>
    <view label="New View">
      <value label="CH1">
        <input>CH1</input>
      </value>
    </view>
  </views>
</phyphox>