This fork of the Zephyr HCI UART example adds a custom HCI Command to allow for timesync between the Bluetooth Host and the Bluetooth Controller. When the HCI LE Read ISO Clock command is received, the Controller toggles a GPIO and returns its current Bluetooth LE ISO Clock in the Command Complete Event.
It has been tested on the nRF5340 Audio DK, but it should work with any nRF5340 dev kit.
- nRF Connect SDK v2.8 or newer
- OGF: 0x3f, OCF: 0x200
- Parameters: Flags (1 Octet) unused
- Response: HCI Command Complete Event with status and 4 bytes timestamp in microseconds
The first Virtual UART (UART1, ...) is Zephyr UART 1 The second Virtual UART (UART2, ...) is Zephyr UART 0
Signal direction as seen from the nRF5340.
PIN | Arduino | MCU | Direction |
---|---|---|---|
TX | D0 | P1.00 | out |
RX | D1 | P1.01 | in |
RTS | D7 | P1.11 | out |
CTS | D8 | P1.10 | in |
Time Sync | D10 | P1.06 | out |
west build --pristine -b nrf5340dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=usb.overlay -DOVERLAY_CONFIG=overlay-usb.conf
west build --pristine -b nrf5340dk/nrf5340/cpuapp
- HCI over second Virtual port / UART 0
- Boot banner on Arduino Header UART (P1.01) / UART 1
west build --pristine -b nrf5340dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=uart1.overlay
- No Boot Banner on Arduino Header UART
The first UART (UART1, P1.04, P1.05) is only available via test points (TP60, TP61, ...) The second UART (UART2, P1.08, P1.09) is connected to the Arduino headers.
Signal direction as seen from the nRF5340.
PIN | Arduino | MCU | Direction |
---|---|---|---|
TX | D0 | P1.09 | out |
RX | D1 | P1.08 | in |
RTS | D7 | P1.11 | out |
CTS | D8 | P1.10 | in |
Time Sync | D10 | P1.01 | out |
west build --pristine -b nrf5340_audio_dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=usb.overlay -DOVERLAY_CONFIG=overlay-usb.conf
west build --pristine -b nrf5340_audio_dk/nrf5340/cpuapp
Release build:
west build --pristine -b nrf5340_audio_dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=uart1.overlay
Debug build:
west build --pristine -b nrf5340_audio_dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=uart1.overlay -DOVERLAY_CONFIG=debug.conf
To use UART 1 via Arduino headers, the virtual UART of the J-Link probe needs to be disabled, e.g. with the JLink Configuration Tool.
Release build:
west build -d nrf54l15-iso --pristine -b nrf54l15dk/nrf54l15/cpuapp
Debug build:
west build -d nrf54l15-iso --pristine -b nrf54l15dk/nrf54l15/cpuapp -- -DOVERLAY_CONFIG=debug.conf
Signal direction as seen from the nRF54L15.
PIN | MCU | Direction |
---|---|---|
TX | P0.00 | out |
RX | P0.01 | in |
RTS | P0.02 | out |
CTS | P0.03 | in |
Time Sync | P1.11 | out |
nRF5340 use Controller configuration in sybuild/ipc_radio/prj.conf
, while other, e.g. nRF54L15, use configuration in le-audio.conf
. Please update both at the same time.
We can check the nRF5340 SoC with if(CONFIG_SOC STREQUAL "nrf5340")
after find_package zephyr.