Hi,
Suddenly I can not connect to my nRF5280 PDK (PCA10056 0.11.0 2018.3)
1. I tried using JLinkExe and also SES, the same result, I got error "Can not connect to JLink via USB". All LEDS off.
2. Double cheking all switch, it was correct as it worked before. I am using linux, so I did "lsusb" but the PDK did not show up on lsusb output.
3. Accidentally I switch on SW10 and then I didn't know how LED5 was on. I run lsusb on the terminal which gave me output "segger", which is correct.
4. JLinkExe and SES can connect to interface MCU, but can not connect to target.
I switch off SW10, measured VSENSE_SW_OUT voltage, it showed 1.5V. This is interesting as I believe it should be around 3V as it is connected to VDD to power up the board.
Measuring VSUPPLY I got 2.89V, which is close to 3V. I suspected something wrong with U17. So I shorted SB39 and viola... the system run as expected. I can connected to SES and JLinkExe, also I can go to BOOTLOADER MODE and download blinky firmware via SES.
I concluded something was wrong with U17. I dig deeper, and found VDD_nRF_SENSE was floating if SW9 was in VDD position and SW10 was in OFF posisition.
I could be wrong here, could you please verify my finding?
Thank you,
-sas
