adaptions for auracaster

.gitignore

@@ -1,7 +1,8 @@
 .settings
 .cproject
 .project
-build
+build*/
 app.jdebug
 app.jdebug.user
 *.jdebug.user
+app.zip

CMakeLists.txt

@@ -9,8 +9,14 @@ set(SRCS
     ${CMAKE_CURRENT_SOURCE_DIR}/src/main.c
 )
 
-if (CONFIG_AUDIO_SYNC_TIMER_USES_RTC)
-    list(APPEND SRCS ${CMAKE_CURRENT_SOURCE_DIR}/src/audio_sync_timer_rtc.c)
+if (CONFIG_SOC_COMPATIBLE_NRF52X)
+    target_sources(app PRIVATE src/controller_time_nrf52.c)
+elseif (CONFIG_SOC_COMPATIBLE_NRF5340_CPUAPP)
+    target_sources(app PRIVATE src/audio_sync_timer_rtc.c)
+elseif (CONFIG_SOC_SERIES_NRF54LX OR CONFIG_SOC_SERIES_NRF54HX)
+    target_sources(app PRIVATE src/controller_time_nrf54.c)
+else()
+    MESSAGE(FATAL_ERROR "Unsupported series")
 endif()
 
 target_sources(app PRIVATE ${SRCS})

Kconfig

@@ -4,7 +4,7 @@ menu "Modules"
 rsource "Kconfig.defaults"
 
 config AUDIO_SYNC_TIMER_USES_RTC
-    bool "Enables syncronization between the APP and NET core running SD"
+    bool "Enables synchronization between the APP and NET core running SD"
     default !BT_LL_ACS_NRF53 && SOC_SERIES_NRF53X
     select NRFX_RTC0
     select NRFX_DPPI

Kconfig.sysbuild

@@ -0,0 +1,10 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+config NRF_DEFAULT_IPC_RADIO
+	default y
+
+source "${ZEPHYR_BASE}/share/sysbuild/Kconfig"

README.md

@@ -1,61 +1,171 @@
 # nRF5340 Bluetooth Controller with Support for LE ISO Timesync
 
-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.
+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.
 
+## Requirements
+- nRF Connect SDK v2.8 or newer
+
 ## HCI LE Read ISO Clock Command
 - OGF: 0x3f, OCF: 0x200
 - Parameters: Flags (1 Octet) unused
 - Response: HCI Command Complete Event with status and 4 bytes timestamp in microseconds
 
 
+
+## nRF58233 Development Kit
+
+The first  Virtual UART (UART1, ...) is Zephyr UART 0
+The second Virtual UART (UART2, ...) is Zephyr UART 1
+
+### Pinout
+
+Signal direction as seen from the nRF52833.
+
+| PIN      | Arduino | MCU   | Direction |
+|----------|---------|-------|-----------|
+|  TX      |    D0   | P0.05 |    out    |
+|  RX      |    D1   | P0.06 |    in     |
+| RTS      |    D7   | P0.07 |    out    |
+| CTS      |    D8   | P0.08 |    in     |
+| Time Sync|    D10  | P1.01 |    out    |
+
+### HCI over UART 0 connected to first Virtual UART in J-Link Probe
+
+Release build:
+```sh
+west build --pristine -b nrf52833dk/nrf52833
+```
+Debug build:
+```sh
+west build --pristine -b nrf52833dk/nrf52833 -- -DOVERLAY_CONFIG=debug.conf
+```
+
+To use UART 0 via Arduino headers, the virtual UART of the J-Link probe needs to be disabled, e.g. with the JLink Configuration Tool.
+
+
+
 ## nRF5340 Development Kit
 
+The first  Virtual UART (UART1, ...) is Zephyr UART 1
+The second Virtual UART (UART2, ...) is Zephyr UART 0
+
+### Pinout
+
+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    |
+
 ### HCI over USB CDC
 
 ```sh
-west build -b nrf5340dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=usb.overlay -DOVERLAY_CONFIG=overlay-usb.conf
+west build --pristine -b nrf5340dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=usb.overlay -DOVERLAY_CONFIG=overlay-usb.conf
 ```
-_HCI over UART and timesync not tested._
+
+
+### HCI over UART 0 connected to second Virtual UART in J-Link Probe 
+```sh
+west build --pristine -b nrf5340dk/nrf5340/cpuapp
+```
+
+- HCI over second Virtual port / UART 0
+- Boot banner on Arduino Header UART (P1.01) / UART 1 
+
+
+### HCI over UART 1 connected to first Virtual UART in J-Link Probe as well as Arduino Headers
+```sh
+west build --pristine -b nrf5340dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=uart1.overlay
+```
+
+- No Boot Banner on Arduino Header UART
+
 
 
 ## nRF5340 Audio DK
 
+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.
+
+### Pinout
+
+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    |
+
+
 ### HCI over USB CDC
 
 ```sh
-west build -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 -- -DEXTRA_DTC_OVERLAY_FILE=usb.overlay -DOVERLAY_CONFIG=overlay-usb.conf
 ```
 
 ### HCI over UART 0 connected to Virtual UART in J-Link Probe
 
 ```sh
-west build -b nrf5340_audio_dk_nrf5340_cpuapp
+west build --pristine -b nrf5340_audio_dk/nrf5340/cpuapp
 ```
 
 ### HCI over UART 1 connected to Virtual UART in J-Link Probe as well as Arduino Headers
 
 Release build:
 ```sh
-west build -b nrf5340_audio_dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=uart1.overlay
+west build --pristine -b nrf5340_audio_dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=uart1.overlay
 ```
 
 Debug build:
 ```sh
-west build -b nrf5340_audio_dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=uart1.overlay -DOVERLAY_CONFIG=debug.conf
+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.
 
-### UART 1 + Time Sync Pinout
 
-Signal direction as seen from the nRF5340.
 
-| PIN      | Arduino |  nrf  | Direction |
-|----------|---------|-------|-----------|
-|  TX      |    D0   | P1.09 |    out    |
-|  RX      |    D1   | P1.08 |    in     |
-| RTS      |    D7   | P1.11 |    out    |
-| CTS      |    D8   | P1.10 |    in     |
-| Timesync |    D10  | P1.01 |    out    |
+## nRF54L15
+
+### HCI over UART 0 connected to second Virtual UART in J-Link Probe
+
+Release build:
+```sh
+west build -d nrf54l15-iso --pristine -b nrf54l15dk/nrf54l15/cpuapp
+```
+Debug build:
+```sh
+west build -d nrf54l15-iso --pristine -b nrf54l15dk/nrf54l15/cpuapp -- -DOVERLAY_CONFIG=debug.conf
+```
+
+To use UART 0 via Arduino headers, the virtual UART of the J-Link probe needs to be disabled, e.g. with the JLink Configuration Tool.
+
+### Pinout
+
+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    |
+
+
+## Maintainer Notes
+- nRF5340 use Controller configuration in `sybuild/ipc_radio/prj.conf`, while others, e.g. nRF54L15, use configuration from `prj.conf`. Please update both at the same time. 
+- We can detect nRF5340 SoC in CMake with `if(CONFIG_SOC STREQUAL "nrf5340")` after find_package zephyr.
+
+ 

boards/nrf52833dk_nrf52833.conf

@@ -0,0 +1,9 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+CONFIG_NRFX_TIMER1=y
+CONFIG_NRFX_RTC2=y
+CONFIG_NRFX_PPI=y

boards/nrf52833dk_nrf52833.overlay

@@ -4,6 +4,17 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+/ {
+	host_interface {
+		compatible = "gpio-outputs";
+		status = "okay";
+		timesync: pin_0 {
+			gpios = <&gpio1 01 GPIO_ACTIVE_HIGH>;
+			label = "Controller to host timesync pin";
+		};
+	};
+};
+
  &uart0 {
 	compatible = "nordic,nrf-uarte";
 	current-speed = <1000000>;

boards/nrf52840dk_nrf52840.conf

@@ -0,0 +1,9 @@
+#
+# Copyright (c) 2024 Nordic Semiconductor
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+CONFIG_NRFX_TIMER1=y
+CONFIG_NRFX_RTC2=y
+CONFIG_NRFX_PPI=y

boards/nrf52840dongle_nrf52840.conf

@@ -2,3 +2,7 @@ CONFIG_USB_DEVICE_STACK=y
 CONFIG_USB_DEVICE_PRODUCT="Zephyr HCI UART sample"
 CONFIG_USB_CDC_ACM=y
 CONFIG_USB_DEVICE_INITIALIZE_AT_BOOT=n
+
+CONFIG_NRFX_TIMER1=y
+CONFIG_NRFX_RTC2=y
+CONFIG_NRFX_PPI=y

boards/nrf5340_audio_dk_nrf5340_cpuapp.overlay

@@ -6,11 +6,7 @@
 		    gpios = <&arduino_header 10 GPIO_ACTIVE_HIGH>;
             label = "Controller to host timesync pin";
         };
-        alternate_toggle: pin_1 {
-		    gpios = <&arduino_header 11 GPIO_ACTIVE_HIGH>;
-            label = "alternate toggle pin";
-        };
-   };
+    };
 };
 
 &uart0 {

boards/nrf54l15dk_nrf54l15_cpuapp.overlay

@@ -0,0 +1,23 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/ {
+	host_interface {
+		compatible = "gpio-outputs";
+		status = "okay";
+		timesync: pin_0 {
+			gpios = <&gpio1 11 GPIO_ACTIVE_HIGH>;
+			label = "Controller to host timesync pin";
+		};
+	};
+};
+
+&uart20 {
+	compatible = "nordic,nrf-uarte";
+	current-speed = <1000000>;
+	status = "okay";
+	hw-flow-control;
+};

boards/nrf54l15dk_nrf54l15_cpuapp_df.overlay

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&uart20 {
+	compatible = "nordic,nrf-uarte";
+	current-speed = <1000000>;
+	status = "okay";
+	hw-flow-control;
+};
+
+&radio {
+	status = "okay";
+	/* This is an example number of antennas that may be available
+	 * on antenna matrix board.
+	 */
+	dfe-antenna-num = <10>;
+	/* This is an example switch pattern that will be used to set an
+	 * antenna for Tx PDU (period before start of Tx CTE).
+	 */
+	dfe-pdu-antenna = <0x0>;
+
+	/* These are example GPIO pin numbers that are provided to
+	 * Radio peripheral. The pins will be acquired by Radio to
+	 * drive antenna switching when AoD is enabled.
+	 */
+	dfegpio0-gpios = <&gpio1 4 0>;
+	dfegpio1-gpios = <&gpio1 5 0>;
+	dfegpio2-gpios = <&gpio1 6 0>;
+	dfegpio3-gpios = <&gpio1 7 0>;
+};

child_image/hci_ipc.conf

@@ -19,8 +19,9 @@ CONFIG_BT_CTLR_ADV_EXT=y
 CONFIG_BT_CTLR_ADV_SET=2
 CONFIG_BT_CTLR_ADV_ISO_SET=2
 CONFIG_BT_CTLR_ADV_ISO_STREAM_COUNT=3
+CONFIG_BT_CTLR_SYNC_PERIODIC_ADV_LIST_SIZE=1
 
-# Support two links as a central, or one link as a peripheral
+# Support six links as a central, or one link as a peripheral
 CONFIG_BT_MAX_CONN=8
 CONFIG_BT_CTLR_SDC_PERIPHERAL_COUNT=2
 

debug.conf

@@ -1,5 +1,8 @@
 CONFIG_ASSERT=y
 
+#CONFIG_BT_DEBUG_MONITOR_RTT=y # custom protocol - bluez needed
+CONFIG_BT_DEBUG_MONITOR_RTT=y
+
 #CONFIG_THREAD_NAME=y
 #CONFIG_THREAD_ANALYZER=y
 #CONFIG_THREAD_ANALYZER_AUTO=y

flash_dongle.sh

@@ -0,0 +1,3 @@
+#! /bin/bash
+nrfutil pkg generate --hw-version 52 --sd-req=0x00  --application ./build_nrf52dongle/merged.hex --application-version 1 app.zip
+nrfutil device program --firmware app.zip --traits nordicDfu

prj.conf

@@ -1,3 +1,23 @@
+# Configure for multiple broadcasters
+CONFIG_BT_EXT_ADV_MAX_ADV_SET=5
+CONFIG_BT_CTLR_ADV_SET=5
+CONFIG_BT_CTLR_ADV_ISO_SET=5
+CONFIG_BT_CTLR_ADV_ISO_STREAM_COUNT=5
+CONFIG_BT_CTLR_SYNC_ISO_STREAM_COUNT=5
+CONFIG_BT_CTLR_ADV_ISO_STREAM_MAX=5
+CONFIG_BT_CTLR_SYNC_PERIODIC_ADV_LIST_SIZE=5
+
+
+CONFIG_BT_BUF_EVT_RX_COUNT=16
+CONFIG_BT_CTLR_ADV_ISO_PDU_LEN_MAX=247
+
+# ISO Transmissions
+CONFIG_BT_CTLR_ISOAL_SOURCES=5
+CONFIG_BT_CTLR_ISO_TX_BUFFERS=8
+CONFIG_BT_CTLR_ISO_TX_BUFFER_SIZE=255
+
+##
+
 CONFIG_CONSOLE=n
 CONFIG_STDOUT_CONSOLE=n
 CONFIG_UART_CONSOLE=n
@@ -8,31 +28,41 @@ CONFIG_BT=y
 CONFIG_BT_HCI_RAW=y
 CONFIG_BT_HCI_RAW_H4=y
 CONFIG_BT_HCI_RAW_H4_ENABLE=y
+CONFIG_BT_BUF_EVT_RX_SIZE=255
 CONFIG_BT_BUF_ACL_RX_SIZE=255
+CONFIG_BT_BUF_ACL_TX_SIZE=251
 CONFIG_BT_BUF_CMD_TX_SIZE=255
 CONFIG_BT_BUF_EVT_DISCARDABLE_SIZE=255
 CONFIG_BT_CTLR_ASSERT_HANDLER=y
-CONFIG_BT_MAX_CONN=16
+#CONFIG_BT_MAX_CONN=16
 CONFIG_BT_TINYCRYPT_ECC=n
-CONFIG_BT_CTLR_DTM_HCI=y
 
-# Enable ISO support
-CONFIG_BT_ISO_PERIPHERAL=y
-CONFIG_BT_ISO_CENTRAL=y
-CONFIG_BT_ISO_BROADCASTER=y
+# Setup ISO Buffer
 CONFIG_BT_ISO_TX_BUF_COUNT=10
 CONFIG_BT_ISO_TX_MTU=251
 CONFIG_BT_ISO_RX_BUF_COUNT=10
 CONFIG_BT_ISO_RX_MTU=251
 
-# setup rpmsg/Bluetooth buffer
-CONFIG_BT_BUF_EVT_RX_COUNT=16
-CONFIG_BT_BUF_EVT_RX_SIZE=255
-CONFIG_BT_BUF_ACL_RX_SIZE=255
-CONFIG_BT_BUF_ACL_TX_SIZE=251
-CONFIG_BT_BUF_CMD_TX_SIZE=255
+# Enable ISO support
+CONFIG_BT_ISO_PERIPHERAL=y
+CONFIG_BT_ISO_CENTRAL=y
+CONFIG_BT_ISO_BROADCASTER=y
+CONFIG_BT_ISO_SYNC_RECEIVER=y
+CONFIG_BT_EXT_ADV=y
+CONFIG_BT_PER_ADV_SYNC_TRANSFER_RECEIVER=y
+CONFIG_BT_PER_ADV_SYNC_TRANSFER_SENDER=y
 
-CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=512
+# Configure Controller
+CONFIG_BT_CTLR_CONN_ISO_GROUPS=1
+CONFIG_BT_CTLR_CONN_ISO_STREAMS=5
+CONFIG_BT_CTLR_ADV_EXT=y
+
+# Support six links as a central, or one link as a peripheral
+CONFIG_BT_MAX_CONN=8
+CONFIG_BT_CTLR_SDC_PERIPHERAL_COUNT=2
+
+# Allow using more than default advertising event length
+CONFIG_BT_CTLR_ADV_DATA_LEN_MAX=512
 
 # Workaround: Unable to allocate command buffer when using K_NO_WAIT since
 # Host number of completed commands does not follow normal flow control.
@@ -41,4 +71,3 @@ CONFIG_BT_BUF_CMD_TX_COUNT=10
 # for the timesync command
 CONFIG_BT_HCI_RAW_CMD_EXT=y
 
-CONFIG_NRFX_TIMER2=y

src/controller_time.h

@@ -0,0 +1,40 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+// BK: based on / taken from ncs/nrf/samples/bluetooth/conn_time_sync/src/controller_time_sync.h
+
+#ifndef CONTROLLER_TIME_SYNC_H__
+#define CONTROLLER_TIME_SYNC_H__
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <zephyr/kernel.h>
+
+/** @brief Obtain the current Bluetooth controller time.
+ *
+ * The timestamps are based upon this clock.
+ *
+ * @return The current controller time.
+ */
+uint64_t controller_time_us_get(void);
+
+/** @brief Set the controller to trigger a PPI event at the given timestamp.
+ *
+ * @param timestamp_us The timestamp where it will trigger.
+ */
+void controller_time_trigger_set(uint64_t timestamp_us);
+
+/** @brief Get the address of the event that will trigger.
+ *
+ * @return The address of the event that will trigger.
+ */
+uint32_t controller_time_trigger_event_addr_get(void);
+
+#endif
+
+/**
+ * @}
+ */

src/controller_time_nrf52.c

@@ -0,0 +1,292 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+/** This file implements controller time management for 52 Series devices
+ *
+ * As the controller clock is not directly accessible, the controller
+ * time is obtained using a mirrored RTC peripheral.
+ * To achieve microsecond accurate toggling, a timer peripheral is also used.
+ */
+
+// BK: taken from ncs/nrf/samples/bluetooth/conn_time_sync/src/controller_time_nrf52.c
+
+#include <zephyr/kernel.h>
+#include <zephyr/sys/barrier.h>
+#include <mpsl_clock.h>
+#include <nrfx_rtc.h>
+#include <nrfx_timer.h>
+#include <helpers/nrfx_gppi.h>
+#include <hal/nrf_egu.h>
+#include <soc.h>
+#include "controller_time.h"
+
+static const nrfx_rtc_t app_rtc_instance = NRFX_RTC_INSTANCE(2);
+static const nrfx_timer_t app_timer_instance = NRFX_TIMER_INSTANCE(1);
+
+static uint8_t ppi_chan_on_rtc_match;
+static volatile uint32_t num_rtc_overflows;
+
+static uint32_t offset_ticks_and_controller_to_app_rtc;
+
+static void rtc_isr_handler(nrfx_rtc_int_type_t int_type)
+{
+	if (int_type == NRFX_RTC_INT_OVERFLOW) {
+		num_rtc_overflows++;
+	}
+}
+
+static void unused_timer_isr_handler(nrf_timer_event_t event_type, void *ctx)
+{
+	ARG_UNUSED(event_type);
+	ARG_UNUSED(ctx);
+}
+
+static int32_t rtc_diff_get(void)
+{
+	uint32_t controller_ticks = nrf_rtc_counter_get(NRF_RTC0);
+	uint32_t app_ticks = nrf_rtc_counter_get(app_rtc_instance.p_reg);
+
+	return controller_ticks - app_ticks;
+}
+
+static int rtc_config(void)
+{
+	int ret;
+
+	const nrfx_rtc_config_t rtc_cfg = NRFX_RTC_DEFAULT_CONFIG;
+
+	ret = nrfx_rtc_init(&app_rtc_instance, &rtc_cfg, rtc_isr_handler);
+	if (ret != NRFX_SUCCESS) {
+		printk("Failed initializing RTC (ret: %d)\n", ret - NRFX_ERROR_BASE_NUM);
+		return -ENODEV;
+	}
+
+#ifndef BT_CTLR_SDC_BSIM_BUILD
+	IRQ_CONNECT(NRFX_IRQ_NUMBER_GET(NRF_RTC_INST_GET(2)), IRQ_PRIO_LOWEST,
+		    NRFX_RTC_INST_HANDLER_GET(2), NULL, 0);
+#else
+	IRQ_CONNECT(NRFX_IRQ_NUMBER_GET(NRF_RTC_INST_GET(2)), 0,
+		    (void *)NRFX_RTC_INST_HANDLER_GET(2), NULL, 0);
+#endif
+
+	nrfx_rtc_overflow_enable(&app_rtc_instance, true);
+	nrfx_rtc_tick_enable(&app_rtc_instance, false);
+	nrfx_rtc_enable(&app_rtc_instance);
+
+	/* To obtain the controller timestamp without modifying the state of RTC0,
+	 * we find the offset between RTC0 and our mirrored RTC.
+	 * We achieve this by reading out the counter value of both of them.
+	 * When the diff between those two have been equal twice, we know the
+	 * time difference in ticks.
+	 */
+
+	uint32_t sync_attempts = 10;
+
+	while (sync_attempts > 0) {
+		sync_attempts--;
+
+		int32_t diff_measurement_1 = rtc_diff_get();
+
+		/* We need to wait half an RTC tick to ensure we are not measuring
+		 * the diff between the two RTCs at the point in time where their
+		 * values are transitioning.
+		 */
+		k_busy_wait(15);
+
+		int32_t diff_measurement_2 = rtc_diff_get();
+
+		if (diff_measurement_1 == diff_measurement_2) {
+			offset_ticks_and_controller_to_app_rtc = diff_measurement_1;
+			return 0;
+		}
+	}
+
+	printk("Controller time sync failure\n");
+	offset_ticks_and_controller_to_app_rtc = 0;
+	return -EINVAL;
+}
+
+static int timer_config(void)
+{
+	int ret;
+	uint8_t ppi_chan_timer_clear_on_rtc_tick;
+	const nrfx_timer_config_t timer_cfg = {
+		.frequency = NRFX_MHZ_TO_HZ(1UL),
+		.mode = NRF_TIMER_MODE_TIMER,
+		.bit_width = NRF_TIMER_BIT_WIDTH_8,
+		.interrupt_priority = NRFX_TIMER_DEFAULT_CONFIG_IRQ_PRIORITY,
+		.p_context = NULL};
+
+	ret = nrfx_timer_init(&app_timer_instance, &timer_cfg, unused_timer_isr_handler);
+	if (ret != NRFX_SUCCESS) {
+		printk("Failed initializing timer (ret: %d)\n", ret - NRFX_ERROR_BASE_NUM);
+		return -ENODEV;
+	}
+
+	/* Clear the TIMER every RTC tick. */
+	if (nrfx_gppi_channel_alloc(&ppi_chan_timer_clear_on_rtc_tick) != NRFX_SUCCESS) {
+		printk("Failed allocating for clearing TIMER on RTC TICK\n");
+		return -ENOMEM;
+	}
+
+	nrfx_gppi_channel_endpoints_setup(ppi_chan_timer_clear_on_rtc_tick,
+					  nrfx_rtc_event_address_get(&app_rtc_instance,
+								     NRF_RTC_EVENT_TICK),
+					  nrfx_timer_task_address_get(&app_timer_instance,
+								      NRF_TIMER_TASK_CLEAR));
+
+	nrfx_gppi_channels_enable(BIT(ppi_chan_timer_clear_on_rtc_tick));
+
+	nrfx_timer_enable(&app_timer_instance);
+
+	return 0;
+}
+
+/** Configure the TIMER and RTC in such a way that microsecond accurate timing can be achieved.
+ *
+ * To get microsecond accurate toggling, we need to combine both the RTC and TIMER peripheral.
+ * That is, both a RTC CC value and TIMER CC value needs to be set.
+ * We should only trigger an EGU task when the TIMER CC value matches after the
+ * RTC CC value matched.
+ * This is achieved using a PPI group. The group is enabled when the RTC CC matches and disabled
+ * again then the TIMER CC matches.
+ */
+int config_egu_trigger_on_rtc_and_timer_match(void)
+{
+	uint8_t ppi_chan_on_timer_match;
+
+	if (nrfx_gppi_channel_alloc(&ppi_chan_on_rtc_match) != NRFX_SUCCESS) {
+		printk("Failed allocating for RTC match\n");
+		return -ENOMEM;
+	}
+
+	if (nrfx_gppi_channel_alloc(&ppi_chan_on_timer_match) != NRFX_SUCCESS) {
+		printk("Failed allocating for TIMER match\n");
+		return -ENOMEM;
+	}
+
+	nrfx_gppi_group_clear(NRFX_GPPI_CHANNEL_GROUP0);
+	nrfx_gppi_group_disable(NRFX_GPPI_CHANNEL_GROUP0);
+	nrfx_gppi_channels_include_in_group(
+		BIT(ppi_chan_on_timer_match) | BIT(ppi_chan_on_rtc_match),
+		NRFX_GPPI_CHANNEL_GROUP0);
+
+	nrfx_gppi_channel_endpoints_setup(ppi_chan_on_rtc_match,
+					  nrfx_rtc_event_address_get(&app_rtc_instance,
+								     NRF_RTC_EVENT_COMPARE_0),
+					  nrfx_gppi_task_address_get(NRFX_GPPI_TASK_CHG0_EN));
+
+	nrfx_gppi_channel_endpoints_setup(ppi_chan_on_timer_match,
+					  nrfx_timer_event_address_get(&app_timer_instance,
+								       NRF_TIMER_EVENT_COMPARE0),
+					  nrf_egu_task_address_get(NRF_EGU0,
+								   NRF_EGU_TASK_TRIGGER0));
+	nrfx_gppi_fork_endpoint_setup(ppi_chan_on_timer_match,
+				      nrfx_gppi_task_address_get(NRFX_GPPI_TASK_CHG0_DIS));
+
+	return 0;
+}
+
+int controller_time_init(void)
+{
+	int ret;
+
+	ret = rtc_config();
+	if (ret) {
+		return ret;
+	}
+
+	ret = timer_config();
+	if (ret) {
+		return ret;
+	}
+
+	return config_egu_trigger_on_rtc_and_timer_match();
+}
+
+static uint64_t rtc_ticks_to_us(uint32_t rtc_ticks)
+{
+	const uint64_t rtc_ticks_in_femto_units = 30517578125UL;
+
+	return (rtc_ticks * rtc_ticks_in_femto_units) / 1000000000UL;
+}
+
+static uint32_t us_to_rtc_ticks(uint32_t timestamp_us)
+{
+	const uint64_t rtc_ticks_in_femto_units = 30517578125UL;
+
+	return ((uint64_t)(timestamp_us) * 1000000000UL) / rtc_ticks_in_femto_units;
+}
+
+uint64_t controller_time_us_get(void)
+{
+	const uint64_t rtc_overflow_time_us = 512000000UL;
+
+	/* On the 52 series the RTC has to task to capture the current RTC value.
+	 * Therefore we cannot capture the TIMER and RTC value simultaneously.
+	 * Therefore we only use the RTC to read out the current time here.
+	 * This will result in an error of maximum one RTC tick.
+	 */
+
+	uint32_t captured_rtc_overflows;
+	uint32_t captured_rtc_ticks;
+
+	while (true) {
+		captured_rtc_overflows = num_rtc_overflows;
+
+		/* Read out RTC ticks after reading number of overflows. */
+		barrier_isync_fence_full();
+
+		captured_rtc_ticks = nrf_rtc_counter_get(app_rtc_instance.p_reg);
+
+		/* Read out number of overflows after reading number of RTC ticks  */
+		barrier_isync_fence_full();
+
+		if (captured_rtc_overflows == num_rtc_overflows) {
+			/* There were no new overflows after reading ticks.
+			 * That is, we can use the captured value.
+			 */
+			break;
+		}
+	}
+
+	return rtc_ticks_to_us(captured_rtc_ticks) +
+	       (captured_rtc_overflows * rtc_overflow_time_us) +
+	       rtc_ticks_to_us(offset_ticks_and_controller_to_app_rtc);
+}
+
+void controller_time_trigger_set(uint64_t timestamp_us)
+{
+	uint64_t timestamp_without_rtc_offset =
+		timestamp_us - rtc_ticks_to_us(offset_ticks_and_controller_to_app_rtc);
+
+	uint32_t num_overflows = timestamp_without_rtc_offset / 512000000UL;
+	uint64_t overflow_time_us = num_overflows * 512000000UL;
+
+	uint32_t rtc_remainder_time_us = timestamp_without_rtc_offset - overflow_time_us;
+	uint32_t rtc_val = us_to_rtc_ticks(rtc_remainder_time_us);
+	uint8_t timer_val =	timestamp_without_rtc_offset - rtc_ticks_to_us(rtc_val);
+
+	/* Ensure the timer value lies between 1 and 30 so that it will
+	 * always be between two RTC ticks.
+	 */
+	timer_val = MAX(timer_val, 1);
+	timer_val = MIN(timer_val, 30);
+
+	if (nrfx_rtc_cc_set(&app_rtc_instance, 0, rtc_val, false) != NRFX_SUCCESS) {
+		printk("Failed setting trigger\n");
+	}
+
+	nrfx_timer_compare(&app_timer_instance, 0, timer_val, false);
+	nrfx_gppi_channels_enable(BIT(ppi_chan_on_rtc_match));
+}
+
+uint32_t controller_time_trigger_event_addr_get(void)
+{
+	return nrf_egu_event_address_get(NRF_EGU0, NRF_EGU_EVENT_TRIGGERED0);
+}
+
+SYS_INIT(controller_time_init, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);

src/controller_time_nrf53_app.c

@@ -0,0 +1,270 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+/** This file implements controller time management for 53 Series devices
+ *
+ * As the controller clock is not directly accessible, the controller
+ * time is obtained using a mirrored RTC peripheral.
+ * The RTC is started upon starting the controller clock on the network core.
+ * To achieve microsecond accurate toggling, a timer peripheral is also used.
+ */
+
+// BK: taken from ncs/nrf/samples/bluetooth/conn_time_sync/src/controller_time_nrf53_app.c
+// - we already have a similar code in audio_sync_timer_rtc.c from nrf5340_audio
+
+#include <zephyr/kernel.h>
+#include <zephyr/init.h>
+#include <zephyr/sys/barrier.h>
+#include <helpers/nrfx_gppi.h>
+#include <nrfx_rtc.h>
+#include <nrfx_timer.h>
+#include <hal/nrf_ipc.h>
+#include <hal/nrf_egu.h>
+#include "conn_time_sync.h"
+
+static const nrfx_rtc_t app_rtc_instance = NRFX_RTC_INSTANCE(0);
+static const nrfx_timer_t app_timer_instance = NRFX_TIMER_INSTANCE(0);
+
+static uint8_t ppi_chan_on_rtc_match;
+static volatile uint32_t num_rtc_overflows;
+
+static void rtc_isr_handler(nrfx_rtc_int_type_t int_type)
+{
+	if (int_type == NRFX_RTC_INT_OVERFLOW) {
+		num_rtc_overflows++;
+	}
+}
+
+static void unused_timer_isr_handler(nrf_timer_event_t event_type, void *ctx)
+{
+	ARG_UNUSED(event_type);
+	ARG_UNUSED(ctx);
+}
+
+static int rtc_config(void)
+{
+	int ret;
+	uint8_t dppi_channel_rtc_start;
+	const nrfx_rtc_config_t rtc_cfg = NRFX_RTC_DEFAULT_CONFIG;
+
+	ret = nrfx_rtc_init(&app_rtc_instance, &rtc_cfg, rtc_isr_handler);
+	if (ret != NRFX_SUCCESS) {
+		printk("Failed initializing RTC (ret: %d)\n", ret - NRFX_ERROR_BASE_NUM);
+		return -ENODEV;
+	}
+
+#ifndef BT_CTLR_SDC_BSIM_BUILD
+	IRQ_CONNECT(NRFX_IRQ_NUMBER_GET(NRF_RTC_INST_GET(0)), IRQ_PRIO_LOWEST,
+		    NRFX_RTC_INST_HANDLER_GET(0), NULL, 0);
+#else
+	IRQ_CONNECT(NRFX_IRQ_NUMBER_GET(NRF_RTC_INST_GET(0)), 0,
+		    (void *)NRFX_RTC_INST_HANDLER_GET(0), NULL, 0);
+#endif
+
+	nrfx_rtc_overflow_enable(&app_rtc_instance, true);
+	nrfx_rtc_tick_enable(&app_rtc_instance, false);
+	nrfx_rtc_enable(&app_rtc_instance);
+
+
+	/* The application core RTC is started synchronously with the controller
+	 * RTC using PPI over IPC.
+	 */
+	ret = nrfx_gppi_channel_alloc(&dppi_channel_rtc_start);
+	if (ret != NRFX_SUCCESS) {
+		printk("nrfx DPPI channel alloc error for starting RTC: %d", ret);
+		return -ENODEV;
+	}
+
+	nrf_ipc_receive_config_set(NRF_IPC, 4, NRF_IPC_CHANNEL_4);
+
+	nrfx_gppi_channel_endpoints_setup(dppi_channel_rtc_start,
+					  nrfx_rtc_task_address_get(&app_rtc_instance,
+								     NRF_RTC_TASK_CLEAR),
+					  nrf_ipc_event_address_get(NRF_IPC,
+								    NRF_IPC_EVENT_RECEIVE_4));
+
+	nrfx_gppi_channels_enable(BIT(dppi_channel_rtc_start));
+
+	return 0;
+}
+
+static int timer_config(void)
+{
+	int ret;
+	uint8_t ppi_chan_timer_clear_on_rtc_tick;
+	const nrfx_timer_config_t timer_cfg = {
+		.frequency = NRFX_MHZ_TO_HZ(1UL),
+		.mode = NRF_TIMER_MODE_TIMER,
+		.bit_width = NRF_TIMER_BIT_WIDTH_8,
+		.interrupt_priority = NRFX_TIMER_DEFAULT_CONFIG_IRQ_PRIORITY,
+		.p_context = NULL};
+
+	ret = nrfx_timer_init(&app_timer_instance, &timer_cfg, unused_timer_isr_handler);
+	if (ret != NRFX_SUCCESS) {
+		printk("Failed initializing timer (ret: %d)\n", ret - NRFX_ERROR_BASE_NUM);
+		return -ENODEV;
+	}
+
+	/* Clear the TIMER every RTC tick. */
+	if (nrfx_gppi_channel_alloc(&ppi_chan_timer_clear_on_rtc_tick) != NRFX_SUCCESS) {
+		printk("Failed allocating for clearing TIMER on RTC TICK\n");
+		return -ENOMEM;
+	}
+
+	nrfx_gppi_channel_endpoints_setup(ppi_chan_timer_clear_on_rtc_tick,
+					  nrfx_rtc_event_address_get(&app_rtc_instance,
+								     NRF_RTC_EVENT_TICK),
+					  nrfx_timer_task_address_get(&app_timer_instance,
+								      NRF_TIMER_TASK_CLEAR));
+
+	nrfx_gppi_channels_enable(BIT(ppi_chan_timer_clear_on_rtc_tick));
+
+	nrfx_timer_enable(&app_timer_instance);
+
+	return 0;
+}
+
+/** Configure the TIMER and RTC in such a way that microsecond accurate timing can be achieved.
+ *
+ * To get microsecond accurate toggling, we need to combine both the RTC and TIMER peripheral.
+ * That is, both a RTC CC value and TIMER CC value needs to be set.
+ * We should only trigger an EGU task when the TIMER CC value
+ * matches after the RTC CC value matched.
+ * This is achieved using a PPI group. The group is enabled when the RTC CC matches and disabled
+ * again then the TIMER CC matches.
+ */
+int config_egu_trigger_on_rtc_and_timer_match(void)
+{
+	uint8_t ppi_chan_on_timer_match;
+
+	if (nrfx_gppi_channel_alloc(&ppi_chan_on_rtc_match) != NRFX_SUCCESS) {
+		printk("Failed allocating for RTC match\n");
+		return -ENOMEM;
+	}
+
+	if (nrfx_gppi_channel_alloc(&ppi_chan_on_timer_match) != NRFX_SUCCESS) {
+		printk("Failed allocating for TIMER match\n");
+		return -ENOMEM;
+	}
+
+	nrfx_gppi_group_clear(NRFX_GPPI_CHANNEL_GROUP0);
+	nrfx_gppi_group_disable(NRFX_GPPI_CHANNEL_GROUP0);
+	nrfx_gppi_channels_include_in_group(
+		BIT(ppi_chan_on_timer_match) | BIT(ppi_chan_on_rtc_match),
+		NRFX_GPPI_CHANNEL_GROUP0);
+
+	nrfx_gppi_channel_endpoints_setup(ppi_chan_on_rtc_match,
+					  nrfx_rtc_event_address_get(&app_rtc_instance,
+								     NRF_RTC_EVENT_COMPARE_0),
+					  nrfx_gppi_task_address_get(NRFX_GPPI_TASK_CHG0_EN));
+	nrfx_gppi_channel_endpoints_setup(ppi_chan_on_timer_match,
+					  nrfx_timer_event_address_get(&app_timer_instance,
+								       NRF_TIMER_EVENT_COMPARE0),
+					  nrfx_gppi_task_address_get(NRFX_GPPI_TASK_CHG0_DIS));
+	nrfx_gppi_fork_endpoint_setup(ppi_chan_on_timer_match,
+				      nrf_egu_task_address_get(NRF_EGU0, NRF_EGU_TASK_TRIGGER0));
+
+	return 0;
+}
+
+int controller_time_init(void)
+{
+	int ret;
+
+	ret = rtc_config();
+	if (ret) {
+		return ret;
+	}
+
+	ret = timer_config();
+	if (ret) {
+		return ret;
+	}
+
+	return config_egu_trigger_on_rtc_and_timer_match();
+}
+
+static uint64_t rtc_ticks_to_us(uint32_t rtc_ticks)
+{
+	const uint64_t rtc_ticks_in_femto_units = 30517578125UL;
+
+	return (rtc_ticks * rtc_ticks_in_femto_units) / 1000000000UL;
+}
+
+static uint32_t us_to_rtc_ticks(uint32_t timestamp_us)
+{
+	const uint64_t rtc_ticks_in_femto_units = 30517578125UL;
+
+	return ((uint64_t)(timestamp_us) * 1000000000UL) / rtc_ticks_in_femto_units;
+}
+
+uint64_t controller_time_us_get(void)
+{
+	/* Simply use the RTC time here.
+	 * It is possible to combine RTC and TIMER information here to get a more accurate
+	 * timestamp. That requires setting up a PPI channel to capture both values simultaneously.
+	 */
+
+	const uint64_t rtc_overflow_time_us = 512000000UL;
+
+	uint32_t captured_rtc_overflows;
+	uint32_t captured_rtc_ticks;
+
+	while (true) {
+		captured_rtc_overflows = num_rtc_overflows;
+
+		/* Read out RTC ticks after reading number of overflows. */
+		barrier_isync_fence_full();
+
+		captured_rtc_ticks = nrf_rtc_counter_get(app_rtc_instance.p_reg);
+
+		/* Read out number of overflows after reading number of RTC ticks  */
+		barrier_isync_fence_full();
+
+		if (captured_rtc_overflows == num_rtc_overflows) {
+			/* There were no new overflows after reading ticks.
+			 * That is, we can use the captured value.
+			 */
+			break;
+		}
+	}
+
+	return rtc_ticks_to_us(captured_rtc_ticks) +
+	       (captured_rtc_overflows * rtc_overflow_time_us);
+}
+
+void controller_time_trigger_set(uint64_t timestamp_us)
+{
+	uint32_t num_overflows = timestamp_us / 512000000UL;
+	uint64_t overflow_time_us = num_overflows * 512000000UL;
+
+	uint32_t remainder_time_us = timestamp_us - overflow_time_us;
+	uint32_t rtc_val = us_to_rtc_ticks(remainder_time_us);
+	uint8_t timer_val = timestamp_us - rtc_ticks_to_us(rtc_val);
+
+	/* Ensure the timer value lies between 1 and 30 so that it will
+	 * always be between two RTC ticks.
+	 */
+	timer_val = MAX(timer_val, 1);
+	timer_val = MIN(timer_val, 30);
+
+	if (nrfx_rtc_cc_set(&app_rtc_instance, 0, rtc_val, false) != NRFX_SUCCESS) {
+		printk("Failed setting trigger\n");
+	}
+
+	nrfx_timer_compare(&app_timer_instance, 0, timer_val, false);
+	nrfx_gppi_channels_enable(BIT(ppi_chan_on_rtc_match));
+}
+
+uint32_t controller_time_trigger_event_addr_get(void)
+{
+	return nrf_egu_event_address_get(NRF_EGU0, NRF_EGU_EVENT_TRIGGERED0);
+}
+
+/* The controller time initialization must happen before
+ * starting the network core.
+ */
+SYS_INIT(controller_time_init, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);

src/controller_time_nrf54.c

@@ -0,0 +1,68 @@
+/*
+ * Copyright (c) 2024 Nordic Semiconductor ASA
+ *
+ * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+ */
+
+/** This file implements controller time management for 54 Series devices
+ */
+
+// BK: taken from ncs/nrf/samples/bluetooth/conn_time_sync/src/controller_time_nrf54.c
+
+#include <zephyr/kernel.h>
+#include <nrfx_grtc.h>
+#include "controller_time.h"
+
+static uint8_t grtc_channel;
+
+int controller_time_init(void)
+{
+	int ret;
+
+	ret = nrfx_grtc_channel_alloc(&grtc_channel);
+	if (ret != NRFX_SUCCESS) {
+		printk("Failed allocating GRTC channel (ret: %d)\n",
+		       ret - NRFX_ERROR_BASE_NUM);
+		return -ENODEV;
+	}
+
+	nrf_grtc_sys_counter_compare_event_enable(NRF_GRTC, grtc_channel);
+
+	return 0;
+}
+
+uint64_t controller_time_us_get(void)
+{
+	int ret;
+	uint64_t current_time_us;
+
+	ret = nrfx_grtc_syscounter_get(&current_time_us);
+	if (ret != NRFX_SUCCESS) {
+		printk("Failed obtaining system time (ret: %d)\n", ret - NRFX_ERROR_BASE_NUM);
+		return 0;
+	}
+
+	return current_time_us;
+}
+
+void controller_time_trigger_set(uint64_t timestamp_us)
+{
+	int ret;
+
+	nrfx_grtc_channel_t chan_data = {
+		.channel = grtc_channel,
+	};
+
+	ret = nrfx_grtc_syscounter_cc_absolute_set(&chan_data, timestamp_us, false);
+	if (ret != NRFX_SUCCESS) {
+		printk("Failed setting CC (ret: %d)\n", ret - NRFX_ERROR_BASE_NUM);
+	}
+}
+
+uint32_t controller_time_trigger_event_addr_get(void)
+{
+	return nrf_grtc_event_address_get(NRF_GRTC,
+					  nrf_grtc_sys_counter_compare_event_get(grtc_channel));
+}
+
+SYS_INIT(controller_time_init, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);

src/main.c

@@ -31,9 +31,12 @@
 #include <zephyr/bluetooth/buf.h>
 #include <zephyr/bluetooth/hci_raw.h>
 
-#include <nrfx_timer.h>
+// nRF5340 - from ncs/nrf/nrf5340_audio example
 #include "audio_sync_timer.h"
 
+// nRF54L15 - from ncs/nrf/samples/bluetooth/conn_time_sync
+#include "controller_time.h"
+
 #define LOG_MODULE_NAME hci_uart
 LOG_MODULE_REGISTER(LOG_MODULE_NAME);
 
@@ -361,7 +364,10 @@ static int hci_uart_init(void)
 
 SYS_INIT(hci_uart_init, APPLICATION, CONFIG_KERNEL_INIT_PRIORITY_DEVICE);
 
-#ifdef CONFIG_AUDIO_SYNC_TIMER_USES_RTC
+#define ENABLE_ISO_TIMESYNC
+
+#ifdef ENABLE_ISO_TIMESYNC
+
 #define TIMESYNC_GPIO  DT_NODELABEL(timesync)
 
 #if DT_NODE_HAS_STATUS(TIMESYNC_GPIO, okay)
@@ -370,13 +376,6 @@ static const struct gpio_dt_spec timesync_pin = GPIO_DT_SPEC_GET(TIMESYNC_GPIO,
 #error "No timesync gpio available!"
 #endif
 
-#define ALTERNATE_TOGGLE_GPIO DT_NODELABEL(alternate_toggle)
-#if DT_NODE_HAS_STATUS(ALTERNATE_TOGGLE_GPIO, okay)
-static const struct gpio_dt_spec alternate_toggle_pin = GPIO_DT_SPEC_GET(ALTERNATE_TOGGLE_GPIO, gpios);
-#else
-#warning "No alternate toggle gpio availabe!"
-#endif
-
 #define  HCI_CMD_ISO_TIMESYNC	(0x200)
 
 struct hci_cmd_iso_timestamp_response {
@@ -392,15 +391,44 @@ uint8_t hci_cmd_iso_timesync_cb(struct net_buf *buf)
 	LOG_INF("buf %p type %u len %u", buf, bt_buf_get_type(buf), buf->len);
 	LOG_INF("buf[0] = 0x%02x", buf->data[0]);
 
-	rsp = bt_hci_cmd_complete_create(BT_OP(BT_OGF_VS, HCI_CMD_ISO_TIMESYNC), sizeof(*response));
-	response = net_buf_add(rsp, sizeof(*response));
-	response->cc.status = BT_HCI_ERR_SUCCESS;
-    response->timestamp = audio_sync_timer_capture();
+	uint32_t timestamp_second_us = 0;
+
+	// Lock interrupts to avoid interrupt between time capture and gpio toggle
+	uint32_t key = arch_irq_lock();
+
+#ifdef CONFIG_SOC_NRF5340_CPUAPP
+	// Get current time
+	uint32_t timestamp_first_us = audio_sync_timer_capture();
+
+	while (1){
+		// get time again and verify that time didn't jump. Work around:
+		// https://devzone.nordicsemi.com/f/nordic-q-a/116907/bluetooth-netcore-time-capture-not-working-100-for-le-audio
+		timestamp_second_us = audio_sync_timer_capture();
+		int32_t timestamp_delta = (int32_t) (timestamp_second_us - timestamp_first_us);
+		if (timestamp_delta < 10){
+			break;
+		}
+		timestamp_first_us = timestamp_second_us;
+	}
+#endif
+
+#if defined(CONFIG_SOC_NRF54L15_CPUAPP) || defined(CONFIG_SOC_NRF52833)
+	timestamp_second_us = (uint32_t) controller_time_us_get();
+#endif
 
 #if DT_NODE_HAS_STATUS(TIMESYNC_GPIO, okay)
 	gpio_pin_toggle_dt( &timesync_pin );
 #endif
 
+	// Unlock interrupts
+	arch_irq_unlock(key);
+
+	// emit event
+	rsp = bt_hci_cmd_complete_create(BT_OP(BT_OGF_VS, HCI_CMD_ISO_TIMESYNC), sizeof(*response));
+	response = net_buf_add(rsp, sizeof(*response));
+	response->cc.status = BT_HCI_ERR_SUCCESS;
+	response->timestamp = timestamp_second_us;
+
 	if (IS_ENABLED(CONFIG_BT_HCI_RAW_H4)) {
 		net_buf_push_u8(rsp, H4_EVT);
 	}
@@ -411,50 +439,8 @@ uint8_t hci_cmd_iso_timesync_cb(struct net_buf *buf)
 }
 #endif
 
-#define TIME_TO_WAIT_MS 1000
-#define SYNC_TOGGLE_TIMER_INSTANCE_NUMBER 2
-static const nrfx_timer_t sync_toggle_timer_instance =
-	NRFX_TIMER_INSTANCE(SYNC_TOGGLE_TIMER_INSTANCE_NUMBER);
-
-static nrfx_timer_config_t cfg = {.frequency = NRFX_MHZ_TO_HZ(1UL),
-				  .mode = NRF_TIMER_MODE_TIMER,
-				  .bit_width = NRF_TIMER_BIT_WIDTH_32,
-				  .interrupt_priority = NRFX_TIMER_DEFAULT_CONFIG_IRQ_PRIORITY,
-				  .p_context = NULL};
-
-static void sync_toggle_timer_isr_handler(nrf_timer_event_t event_type, void *p_context)
-{
-    ARG_UNUSED(p_context);
-    if(event_type == NRF_TIMER_EVENT_COMPARE1)
-    {
-        char * p_msg = p_context;
-        uint32_t remainder_us = nrf_timer_cc_get(NRF_TIMER2,
-						 NRF_TIMER_CC_CHANNEL1);
-
-#if DT_NODE_HAS_STATUS(ALTERNATE_TOGGLE_GPIO, okay)
-        gpio_pin_toggle_dt( &alternate_toggle_pin );
-#endif
-
-        LOG_INF("%d\n", remainder_us );
-        printf("Timer finished. Context passed to the handler: >%s<", p_msg);
-    }
-}
-
 int main(void)
 {
-    // timer setup
-    nrfx_err_t ret;
-    ret = nrfx_timer_init(&sync_toggle_timer_instance, &cfg, sync_toggle_timer_isr_handler);
-    if (ret - NRFX_ERROR_BASE_NUM) {
-        LOG_ERR("nrfx timer init error: %d", ret);
-        return -ENODEV;
-    }
-    uint32_t desired_ticks = nrfx_timer_ms_to_ticks(&sync_toggle_timer_instance, TIME_TO_WAIT_MS);
-    nrfx_timer_compare(&sync_toggle_timer_instance, NRF_TIMER_CC_CHANNEL1, desired_ticks, true);
-    IRQ_CONNECT(NRFX_IRQ_NUMBER_GET(NRF_TIMER_INST_GET(SYNC_TOGGLE_TIMER_INSTANCE_NUMBER)), IRQ_PRIO_LOWEST,
-            NRFX_TIMER_INST_HANDLER_GET(SYNC_TOGGLE_TIMER_INSTANCE_NUMBER), 0, 0);
-    nrfx_timer_enable(&sync_toggle_timer_instance);
-
 	/* incoming events and data from the controller */
 	static K_FIFO_DEFINE(rx_queue);
 	int err;
@@ -491,11 +477,7 @@ int main(void)
 		}
 	}
 
-#if DT_NODE_HAS_STATUS(ALTERNATE_TOGGLE_GPIO, okay)
-    gpio_pin_configure_dt(&alternate_toggle_pin, GPIO_OUTPUT_INACTIVE);
-#endif
-
-#ifdef CONFIG_AUDIO_SYNC_TIMER_USES_RTC
+#ifdef ENABLE_ISO_TIMESYNC
 	/* Register iso_timesync command */
 	static struct bt_hci_raw_cmd_ext cmd_list = {
 	    .op = BT_OP(BT_OGF_VS, HCI_CMD_ISO_TIMESYNC),

sysbuild/ipc_radio/prj.conf

@@ -0,0 +1,58 @@
+#
+# Copyright (c) 2023 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+# Addedby me
+CONFIG_BT_EXT_ADV_MAX_ADV_SET=2
+
+##
+
+
+CONFIG_HEAP_MEM_POOL_SIZE=8192
+CONFIG_MAIN_STACK_SIZE=2048
+CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
+
+CONFIG_MBOX=y
+CONFIG_IPC_SERVICE=y
+
+CONFIG_BT=y
+CONFIG_BT_HCI_RAW=y
+CONFIG_BT_CTLR_ASSERT_HANDLER=y
+
+CONFIG_BT_ISO_PERIPHERAL=y
+CONFIG_BT_ISO_CENTRAL=y
+CONFIG_BT_ISO_BROADCASTER=y
+CONFIG_BT_ISO_SYNC_RECEIVER=y
+CONFIG_BT_EXT_ADV=y
+CONFIG_BT_PER_ADV_SYNC_TRANSFER_RECEIVER=y
+CONFIG_BT_PER_ADV_SYNC_TRANSFER_SENDER=y
+
+CONFIG_BT_CTLR_ADV_ISO_SET=2
+CONFIG_BT_CTLR_ADV_SET=2
+CONFIG_BT_CTLR_ADV_ISO_STREAM_COUNT=2
+CONFIG_BT_CTLR_CONN_ISO_GROUPS=1
+CONFIG_BT_CTLR_CONN_ISO_STREAMS=2
+CONFIG_BT_CTLR_SYNC_ISO_STREAM_COUNT=3
+CONFIG_BT_CTLR_SYNC_PERIODIC_ADV_LIST_SIZE=1
+
+
+# Support six links as a central, or one link as a peripheral
+CONFIG_BT_MAX_CONN=8
+CONFIG_BT_CTLR_SDC_PERIPHERAL_COUNT=2
+
+# Allow using more than default advertising event length
+CONFIG_BT_CTLR_ADV_DATA_LEN_MAX=251
+
+# To present the audio at the right point in time, we need the controller and
+# audio clock to be synchronized
+CONFIG_MPSL_TRIGGER_IPC_TASK_ON_RTC_START=y
+CONFIG_MPSL_TRIGGER_IPC_TASK_ON_RTC_START_CHANNEL=4
+
+# Needed for builds with nrf21540
+# Can also be set to 20, but check local restrictions first
+#CONFIG_BT_CTLR_TX_PWR_ANTENNA=10
+#CONFIG_MPSL_FEM_NRF21540_TX_GAIN_DB=10
+
+CONFIG_IPC_RADIO_BT=y
+CONFIG_IPC_RADIO_BT_HCI_IPC=y

sysbuild/ipc_radio/prj_release.conf

@@ -0,0 +1,58 @@
+#
+# Copyright (c) 2023 Nordic Semiconductor ASA
+#
+# SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
+#
+
+CONFIG_HEAP_MEM_POOL_SIZE=8192
+CONFIG_MAIN_STACK_SIZE=2048
+CONFIG_SYSTEM_WORKQUEUE_STACK_SIZE=2048
+
+CONFIG_MBOX=y
+CONFIG_IPC_SERVICE=y
+
+CONFIG_BT=y
+CONFIG_BT_HCI_RAW=y
+CONFIG_BT_CTLR_ASSERT_HANDLER=y
+
+CONFIG_BT_ISO_PERIPHERAL=y
+CONFIG_BT_ISO_CENTRAL=y
+CONFIG_BT_ISO_BROADCASTER=y
+CONFIG_BT_ISO_SYNC_RECEIVER=y
+CONFIG_BT_EXT_ADV=y
+CONFIG_BT_PER_ADV_SYNC_TRANSFER_RECEIVER=y
+CONFIG_BT_PER_ADV_SYNC_TRANSFER_SENDER=y
+
+CONFIG_BT_CTLR_ADV_ISO_SET=2
+CONFIG_BT_CTLR_ADV_SET=2
+CONFIG_BT_CTLR_ADV_ISO_STREAM_COUNT=2
+CONFIG_BT_CTLR_CONN_ISO_GROUPS=1
+CONFIG_BT_CTLR_CONN_ISO_STREAMS=2
+CONFIG_BT_CTLR_SYNC_ISO_STREAM_COUNT=3
+CONFIG_BT_CTLR_SYNC_PERIODIC_ADV_LIST_SIZE=1
+
+# Support six links as a central, or one link as a peripheral
+CONFIG_BT_MAX_CONN=8
+CONFIG_BT_CTLR_SDC_PERIPHERAL_COUNT=2
+
+# Allow using more than default advertising event length
+CONFIG_BT_CTLR_ADV_DATA_LEN_MAX=251
+
+# To present the audio at the right point in time, we need the controller and
+# audio clock to be synchronized
+CONFIG_MPSL_TRIGGER_IPC_TASK_ON_RTC_START=y
+CONFIG_MPSL_TRIGGER_IPC_TASK_ON_RTC_START_CHANNEL=4
+
+CONFIG_IPC_RADIO_BT=y
+CONFIG_IPC_RADIO_BT_HCI_IPC=y
+
+# General
+CONFIG_DEBUG=n
+CONFIG_ASSERT=n
+CONFIG_STACK_USAGE=n
+CONFIG_THREAD_MONITOR=n
+CONFIG_SERIAL=n
+CONFIG_CONSOLE=n
+CONFIG_PRINTK=n
+CONFIG_UART_CONSOLE=n
+CONFIG_BOOT_BANNER=n

usb.overlay

@@ -15,3 +15,15 @@
 		compatible = "zephyr,cdc-acm-uart";
 	};
 };
+
+
+/ {
+	host_interface {
+		compatible = "gpio-outputs";
+		status = "okay";
+		timesync: pin_0 {
+			gpios = <&gpio1 01 GPIO_ACTIVE_HIGH>;
+			label = "Controller to host timesync pin";
+		};
+	};
+};