When the E10-1 module is attached and GPIO 26 is driven high, there’s an unexpected signal observed that occurs about every 1.3 seconds. This does not occur If the E10-1 is not attached.
I tested this on older reTerminal Raspbian images as well as the latest reTerminal Raspbian image and the same result was observed.
Steps to reproduce:
- Attach (stock, unmodified) E10-1 module to (stock, unmodified) reTerminal.
- Connect an oscilloscope probe to ground and GPIO 26 on the exposed header pins.
Observations w/ E10-1 attached:
Here’s when GPIO26 is driven from low to high. You can see the activation of the unexpected signal.
Here’s the frequency measurement of the signal:
Zooming into the signal and measuring again:
Observations WITHOUT E10-1:
GPIO 26 driven high. Clean, no unexpected signal.
I looked at the extension module interface schematics and pinout diagrams and there’s nothing in the schematics that indicate GPIO 26 is used for other functions.
@lakshan Is this a known issue on your side? This makes GPIO 26 unusable with the E10-1 module attached.