Issue Custom Board

[Romain Plougoulm]

Hello, I’m working on my own custom board based on the nrf52832 (QFAABB). Here the schematic:

I succeed to flash the board with the nrf52DK (PCA10036) via the debug out port (SDK : nRF52_SDK_0.9.1_3639cc9 and SD : s132_nrf52_1.0.0-3.alpha_softdevice.hex). The ble_app_beacon example works well on my board. But when I when I run the ble_app_uart exemple over my custom board I don’t have any signal (the external 32MHz Xtal doesn’t oscillate) and I don’t understand why. Have you an idea of the cause of this behaviour?

Please. Best regards.

[Øyvind Karlsen]

Hi,

Does the advertising work in the ble_app_uart example?

Are C61 and C60 = 2xC_L - 4 pF, where C_L is the load capacitance of the crystal found in its datasheet? (same for C56 and C57)

If you have an oscilloscope test your crystals by having TIMER1 and RTC1 toggle GPIOs and observe that the output frequency is a clean multiple of the crystal.

Do you have a spectrum analyzer, if so, what did you see when measuring the ble_app_beacon code? Frequency drifts indicate bad 32MHz clocks.

What is the precision of your OSC2? If it is different from 20ppm you will have to change the line SOFTDEVICE_HANDLER_INIT(NRF_CLOCK_LFCLKSRC_XTAL_20_PPM, NULL);.

Best regards,

Øyvind

[Romain Plougoulm]

Thanks for your answer, I found a solution for my issue. I bought a newer version of the nrf52DK and the ble_uart example works now on my custom board. I don’t understand why, probably a compatibility problem with my SoC.

Best regards.

RP