Hi,
I have been using the nRF55 DK, through the external debug interface (P20), for programming my custom boards since I started working with the nRF52832 chip. So far, for programming, I have been using the board's default configurations, so the USB's regulated 3.3V goes through the reverse voltage protection diode and gets dropped to around 2.84V. Basically, what I have been doing is that I power the custom board with VDD (2.84V) on the DK, and connect the SWD pins in a similar fashion described in this YouTube video: Nordic Semiconductor - Programming and debugging custom nRF52 devices.
Yesterday, I was reviewing the nRF52 DK User Guide, because I wanted to short SB10 (i.e. "solder bridge 10" on the nRF52 DK) to bypass the reverse voltage protection diode on the USB power. Among other things, this would allow me to connect my computer to UART_TX on my custom board without having to connect and disconnect the SWD each time I want to flash the custom board.
But, in the nRF52 DK's user guide, in section 6.10, the following is stated:
Important: The voltage supported by external debugging/programming is 3.0V.
My question is therefore the following:
If I short SB10 on nRF52 DK and VDD becomes 3.3V, will I be able to use the nRF52 DK for external programming through SWD at a 3.3V logic? In other words, is the warning in the user guide (section 6.10) based on the fact that the board's default configuration yields a VDD of 2.84V, or is there another reason for the 3.0V programming/debugging logic warning?
As a side-question, my understanding is that once SB10 has been shorted I'll have to make sure to remove to coin cell battery before connecting the USB and powering on the nRF52 DK. Is this correct?
Thank you very much for your time and support. A+ :)
Frank
