Have a USB powered Chengdu Ebyte nRF52840 Dongle (PCA100059-style) that has the following:
- USB 5V
- VBUS pin : connected directly to USB 5V
- VDD pin: not connected to VBUS, but has a solder-cut (open) between VDD and VBUS
- Missing VDDH pin
- the "V" pin for the SWD programming setup is connected to the VDD pin
When powered via USB then VBUS has 5V and VDD has 3V.
When USB is not connected and instead powered via VBUS with 4.2V (battery) connected then VDD has 3V.
When USB is not connected and VBUS is not connected and instead VDD powered with 3.3V then VBUS has 3V.
Although I plan to power the dongle via an external 3.3V regulator connected to the VDD pin, it would be good to know where is the VDDH circuit? And if they did not bring it out VDDH as a pin, how is it connected inside?
The manual does not have a schematics albeit seems to follow the actual Nordic PCA10059 numbering.
https://www.ebyte.com/en/downpdf.aspx?id=1185
Would appreciate any assistance.