Zephyr's hci_uart works well only after starting JLinkRTTLogger

[Youngdo Lee]

Hi all,

Our custom board has 2 MCUs connected each other via UART to implement 2-chip configuration.

One is the main MCU which has Cortex R4 and the other is nRF52810.

All of them runs Zephyr respectively.

CR4(CortexR4) runs Zephyr's iBeacon sample and nRF52810 runs Zephyr's hci_uart sample.

If I started JLinkRTTLogger, the system works well.

But if I don't start JLinkRTTLogger, it seems like the nRF52810 doesn't boot properly.

Do you have any idea of it ?

Thank you in advance.

---

Through more test, I found that 'nrfjprog --reset' makes the system work well.

Our custom board doesn't connect nRF52810's nRESET pin to anything.(NC)

Do I have to reset the nRF52810 after supplying VDD ?

Is there any way to reset the nRF52810 in Zephyr without controlling nRESET pin?

[Youngdo Lee]

Self answer:

The problem was a configuration issue.

I used the default configuration which enables DCDC by default.(samples/bluetooth/hci_uart/nrf5.conf)

But our H/W doesn't have external LC filters connected to DCC, so we shouldn't enable DCDC.

Adding CONFIG_BOARD_ENABLE_DCDC=n to nrf5.conf solved the problem.

Thanks anyway.

[bhstalel]

Youngdo Lee , Can you give me the hex hci_uart example for nRF52832 ? I'm unable to compile it ,