updated code for nRF Connect SDK v2.8.0

README.md

@@ -1,14 +1,9 @@
 # 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
@@ -30,25 +25,25 @@ _HCI over UART and timesync not tested._
 ### HCI over USB CDC
 
 ```sh
-west build --pristine -b nrf5340_audio_dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=usb.overlay -DOVERLAY_CONFIG=overlay-usb.conf
+west build -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 --pristine -b nrf5340_audio_dk_nrf5340_cpuapp
+west build -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 --pristine -b nrf5340_audio_dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=uart1.overlay
+west build -b nrf5340_audio_dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=uart1.overlay
 ```
 
 Debug build:
 ```sh
-west build --pristine -b nrf5340_audio_dk/nrf5340/cpuapp -- -DEXTRA_DTC_OVERLAY_FILE=uart1.overlay -DOVERLAY_CONFIG=debug.conf
+west build -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.

child_image/hci_ipc.conf

@@ -19,7 +19,6 @@ 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
 CONFIG_BT_MAX_CONN=8

src/main.c

@@ -37,9 +37,8 @@
 #define LOG_MODULE_NAME hci_uart
 LOG_MODULE_REGISTER(LOG_MODULE_NAME);
 
-static const struct device *const hci_uart_dev  = DEVICE_DT_GET(DT_CHOSEN(zephyr_bt_c2h_uart));
-static const struct device *const gmap_uart_dev = DEVICE_DT_GET(DT_NODELABEL(uart1));
-
+static const struct device *const hci_uart_dev =
+	DEVICE_DT_GET(DT_CHOSEN(zephyr_bt_c2h_uart));
 static K_THREAD_STACK_DEFINE(tx_thread_stack, CONFIG_BT_HCI_TX_STACK_SIZE);
 static struct k_thread tx_thread_data;
 static K_FIFO_DEFINE(tx_queue);
@@ -68,30 +67,6 @@ static K_FIFO_DEFINE(uart_tx_queue);
  */
 #define H4_DISCARD_LEN 33
 
-#ifdef CONFIG_AUDIO_SYNC_TIMER_USES_RTC
-#define TIMESYNC_GPIO  DT_NODELABEL(timesync)
-
-#if DT_NODE_HAS_STATUS(TIMESYNC_GPIO, okay)
-static const struct gpio_dt_spec timesync_pin = GPIO_DT_SPEC_GET(TIMESYNC_GPIO, gpios);
-#else
-#error "No timesync gpio available!"
-#endif
-
-#define ALTERNATE_TOGGLE_GPIO DT_NODELABEL(alternate_toggle)
-static const struct gpio_dt_spec alternate_toggle_pin = GPIO_DT_SPEC_GET(ALTERNATE_TOGGLE_GPIO, gpios);
-
-#endif
-
-// enable to have alternate toggle indicate time from audio in to sdu sync ref in UGT to UGG direction
-#define PERIPHERAL_TO_CENTRAL_AUDIO_IN_TO_SDU_SYNC_REF
-
-// Presentation time from Audio to SDU Sync Ref (UGT->UGG) resp. SDU Sync Ref to Audio Out (UGG->UGT)
-// HS timer on nRF5340 seems to be off: 60000 ticks = 59372 us
-#define PRESENTATION_TIME_US 60634
-
-static uint32_t last_sdu_sync_ref_us;
-static uint32_t sdu_interval_us;
-
 static int h4_read(const struct device *uart, uint8_t *buf, size_t len)
 {
 	int rx = uart_fifo_read(uart, buf, len);
@@ -284,15 +259,6 @@ static void tx_thread(void *p1, void *p2, void *p3)
 
 		/* Wait until a buffer is available */
 		buf = k_fifo_get(&tx_queue, K_FOREVER);
-
-#if DT_NODE_HAS_STATUS(TIMESYNC_GPIO, okay)
-		// toggle GPIO and send 'B' for each TX packet to be able to capture by Logic Analzyer
-		if (bt_buf_get_type(buf) == BT_BUF_ISO_OUT) {
-			gpio_pin_toggle_dt( &timesync_pin );
-			uart_poll_out(gmap_uart_dev, 'B');
-		}
-#endif
-
 		/* Pass buffer to the stack */
 		err = bt_send(buf);
         if (err!=BT_HCI_ERR_SUCCESS) {
@@ -396,6 +362,20 @@ 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 TIMESYNC_GPIO  DT_NODELABEL(timesync)
+
+#if DT_NODE_HAS_STATUS(TIMESYNC_GPIO, okay)
+static const struct gpio_dt_spec timesync_pin = GPIO_DT_SPEC_GET(TIMESYNC_GPIO, gpios);
+#else
+#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)
 
@@ -412,38 +392,15 @@ 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]);
 
-	uint32_t timestamp_second_us;
-
-	// Lock interrupts to avoid interrupt between time capture and gpio toggle
-	uint32_t key = arch_irq_lock();
-
-	// 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;
-	}
+	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();
 
 #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);
 	}
@@ -454,135 +411,56 @@ uint8_t hci_cmd_iso_timesync_cb(struct net_buf *buf)
 }
 #endif
 
-uint16_t little_endian_read_16(const uint8_t * buffer, int position){
-	return (uint16_t)(((uint16_t) buffer[position]) | (((uint16_t)buffer[position+1]) << 8));
-}
-
-static uint32_t little_endian_read_32(const uint8_t * buffer, int position){
-    return ((uint32_t) buffer[position]) | (((uint32_t)buffer[position+1]) << 8) | (((uint32_t)buffer[position+2]) << 16) | (((uint32_t) buffer[position+3]) << 24);
-}
-
-#if DT_NODE_HAS_STATUS(TIMESYNC_GPIO, okay)
-
-// make sure there's no IRQ between getting the time and the toggle
-// verify timestamp as it's 100% coorect
-#define LOCK_IRQS_FOR_SYNC_TOGGLE
-static uint32_t toggle_and_get_bluetooth_time_us(void) {
-	uint32_t timestamp_toggle_us;
-
-#ifdef LOCK_IRQS_FOR_SYNC_TOGGLE
-	// Lock interrupts
-	uint32_t key = arch_irq_lock();
-#endif
-
-	while (1){
-		// Get current time once
-		timestamp_toggle_us = audio_sync_timer_capture();
-
-		// Get current time again
-		uint32_t timestamp_toggle_us_verify = audio_sync_timer_capture();
-
-		// check if time didn't jump
-		int32_t timestamp_delta = (int32_t) (timestamp_toggle_us_verify - timestamp_toggle_us);
-		if ((timestamp_delta >= 0) && (timestamp_delta < 10)){
-			break;
-		}
-	}
-
-	// Toggle
-	gpio_pin_toggle_dt( &timesync_pin );
-
-#ifdef LOCK_IRQS_FOR_SYNC_TOGGLE
-	// Unlock interrupts
-	arch_irq_unlock(key);
-#endif
-
-	return timestamp_toggle_us;
-}
-
-#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 volatile enum {
-	ALTERNATE_TOGGLE_STATE_IDLE,
-	ALTERNATE_TOGGLE_STATE_W2_RISE,
-	ALTERNATE_TOGGLE_STATE_W2_FALL
-} alternate_toggle_state = ALTERNATE_TOGGLE_STATE_IDLE;
+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);
 
-static volatile uint32_t alternate_toggle_fall_us;
+#if DT_NODE_HAS_STATUS(ALTERNATE_TOGGLE_GPIO, okay)
+        gpio_pin_toggle_dt( &alternate_toggle_pin );
+#endif
 
-static uint32_t get_local_time_us(void) {
-	nrf_timer_cc_set(NRF_TIMER2, NRF_TIMER_CC_CHANNEL2, 0);
-	nrf_timer_task_trigger(NRF_TIMER2, nrf_timer_capture_task_get(NRF_TIMER_CC_CHANNEL2));
-	uint32_t current_time_us = nrf_timer_cc_get(NRF_TIMER2, NRF_TIMER_CC_CHANNEL2);
-	while (current_time_us == 0) {
-		current_time_us = nrf_timer_cc_get(NRF_TIMER2, NRF_TIMER_CC_CHANNEL2);
-	}
-	return current_time_us;
-}
-
-static void alternate_toggle_timer_isr_handler(nrf_timer_event_t event_type, void *p_context){
-	ARG_UNUSED(p_context);
-	if(event_type == NRF_TIMER_EVENT_COMPARE1){
-		switch (alternate_toggle_state) {
-			case ALTERNATE_TOGGLE_STATE_W2_RISE:
-				alternate_toggle_state = ALTERNATE_TOGGLE_STATE_W2_FALL;
-				gpio_pin_set_dt(&alternate_toggle_pin, 1);
-				nrfx_timer_compare(&sync_toggle_timer_instance, NRF_TIMER_CC_CHANNEL1, alternate_toggle_fall_us, true);
-				break;
-			case ALTERNATE_TOGGLE_STATE_W2_FALL:
-				alternate_toggle_state = ALTERNATE_TOGGLE_STATE_IDLE;
-				gpio_pin_set_dt(&alternate_toggle_pin, 0);
-				break;
-			default:
-				__ASSERT(0, "Unknown state");
-				break;
-		}
-	}
-}
-
-static void alternate_toggle_setup(uint32_t rise_us, uint32_t fall_us) {
-	alternate_toggle_fall_us = fall_us;
-	alternate_toggle_state = ALTERNATE_TOGGLE_STATE_W2_RISE;
-	nrfx_timer_compare(&sync_toggle_timer_instance, NRF_TIMER_CC_CHANNEL1, rise_us, true);
+        LOG_INF("%d\n", remainder_us );
+        printf("Timer finished. Context passed to the handler: >%s<", p_msg);
+    }
 }
 
 int main(void)
 {
-	// toggle timer setup
-	nrfx_err_t ret;
-	ret = nrfx_timer_init(&sync_toggle_timer_instance, &cfg, alternate_toggle_timer_isr_handler);
-	if (ret - NRFX_ERROR_BASE_NUM) {
-		LOG_ERR("nrfx timer init error: %d", ret);
-		return -ENODEV;
-	}
-	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);
-	alternate_toggle_state = ALTERNATE_TOGGLE_STATE_IDLE;
+    // 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;
 
 	LOG_DBG("Start");
-	__ASSERT(hci_uart_dev, "HCI UART device is NULL");
-
-	if (!device_is_ready(gmap_uart_dev)) {
-		printk("GMAP UART device is not ready\n");
-		return -1;
-	}
+	__ASSERT(hci_uart_dev, "UART device is NULL");
 
 	/* Enable the raw interface, this will in turn open the HCI driver */
 	bt_enable_raw(&rx_queue);
@@ -613,6 +491,10 @@ 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
 	/* Register iso_timesync command */
 	static struct bt_hci_raw_cmd_ext cmd_list = {
@@ -625,10 +507,6 @@ int main(void)
 	gpio_pin_configure_dt(&timesync_pin, GPIO_OUTPUT_INACTIVE);
 #endif
 
-#if DT_NODE_HAS_STATUS(TIMESYNC_GPIO, okay)
-	gpio_pin_configure_dt(&alternate_toggle_pin, GPIO_OUTPUT_INACTIVE);
-#endif
-
 	bt_hci_raw_cmd_ext_register(&cmd_list, 1);
 #endif
 
@@ -640,125 +518,20 @@ int main(void)
 			NULL, NULL, NULL, K_PRIO_COOP(7), 0, K_NO_WAIT);
 	k_thread_name_set(&tx_thread_data, "HCI uart TX");
 
-	while (1) {
+#if 0
+    while (1) {
+		uint8_t c = 'A';
+		uart_fifo_fill(hci_uart_dev, &c, 1);
+		uart_irq_tx_enable(hci_uart_dev);
+		k_sleep( K_MSEC(100) );
+	}
+    return 0;
+#endif
+
+    while (1) {
 		struct net_buf *buf;
 
-		buf = net_buf_get(&rx_queue, K_FOREVER);
-
-#if DT_NODE_HAS_STATUS(TIMESYNC_GPIO, okay)
-		// ISO RX Measurement Code
-		const uint8_t * packet = buf->data;
-		if (packet[0] == H4_ISO){
-
-			// TODO: check if packets contains timestamp. all Controller -> Host packets have it so far
-
-			// get rx timestamp = sdu sync reference: Packet Type (1) | ISO Header (4) | Timestamp (if TS flag is set)
-			const uint32_t timestamp_sdu_sync_reference_us = little_endian_read_32(packet, 5);
-
-			// ignore empty ISO packets
-			const uint16_t data_total_length = little_endian_read_16(packet, 3);
-			if (data_total_length > 8) {
-
-				// get current Bluetooth time + toggle GPIO
-				const uint32_t bluetooth_time_us = toggle_and_get_bluetooth_time_us();
-
-				// calculate time of toggle relative to sdu sync reference usually
-				// - negative for UGT->UGG and
-				// - positive in UGT->UGG direction)
-				const int32_t delta_us = (int32_t)(bluetooth_time_us - timestamp_sdu_sync_reference_us);
-
-				// convert to string and send over UART and RTT
-				char delta_string[15];
-				const uint8_t first_payload_byte = packet[13];
-				snprintf(delta_string, sizeof(delta_string), "R%+06d@%02X!", delta_us,first_payload_byte);
-				for (size_t i = 0; delta_string[i] != '\0'; i++) {
-					uart_poll_out(gmap_uart_dev, delta_string[i]);
-				}
-
-				LOG_INF("Toggle %8u - SDU Sync Reference %8u -> delta %s", bluetooth_time_us, timestamp_sdu_sync_reference_us, delta_string);
-			}
-		}
-
-    	if (packet[0] == H4_EVT) {
-    		if (packet[1] == 0x0e) {
-    			uint16_t opcode = little_endian_read_16(packet, 4);
-    			const uint16_t hci_opcode_reset = 0x0c03;;
-    			if (opcode == hci_opcode_reset) {
-    				LOG_INF("HCI Reset");
-    				last_sdu_sync_ref_us = 0;
-    				sdu_interval_us = 0;
-    			}
-    			const uint16_t hci_opcode_le_read_tx_iso_sync = 0x2061;
-    			if (opcode == hci_opcode_le_read_tx_iso_sync) {
-    				const uint8_t * return_params = &packet[6];
-
-    				// get current Bluetooth time + toggle GPIO
-    				const uint32_t bluetooth_time_us = toggle_and_get_bluetooth_time_us();
-
-    				// get current local time
-    				const uint32_t local_time_us = get_local_time_us();
-
-    				// status: 0
-    				uint16_t handle = little_endian_read_16(return_params, 1);
-    				ARG_UNUSED(handle);
-
-    				// get packet sequence number (assuming counter == packet_sequence_number & 0xff)
-    				const uint16_t packet_sequence_number = little_endian_read_16(return_params, 3);
-
-    				// get tx timestamp = sdu sync reference: Packet Type (1) | ISO Header (4) | Timestamp (if TS flag is set)
-    				const uint32_t iso_tx_us = little_endian_read_32(return_params, 5);
-
-    				// get SDU interval based on sdu sync ref interval (round to the next 100 us)
-    				if (last_sdu_sync_ref_us > 0) {
-    					const uint32_t sdu_interval_reported_us = iso_tx_us - last_sdu_sync_ref_us;
-    					sdu_interval_us = ((sdu_interval_reported_us + 50) / 100 ) * 100;
-    				}
-    				last_sdu_sync_ref_us = iso_tx_us;
-
-    				// calculate time of toggle relative to sdu sync reference (usually negative as the packet is received before it should be played)
-    				const int32_t delta_us = (int32_t)(bluetooth_time_us - iso_tx_us);
-
-    				// convert to string and send over UART and RTT
-    				char delta_string[15];
-    				snprintf(delta_string, sizeof(delta_string), "T%+06d@%02X!", delta_us,packet_sequence_number & 0xff);
-    				for (size_t i = 0; delta_string[i] != '\0'; i++) {
-    					uart_poll_out(gmap_uart_dev, delta_string[i]);
-    				}
-    				// LOG_INF("Toggle %8u - TX  %8u - %02X-> delta %s", bluetooth_time_us, iso_tx_us, packet_sequence_number, delta_string);
-
-#ifdef PERIPHERAL_TO_CENTRAL_AUDIO_IN_TO_SDU_SYNC_REF
-    				// schedule Audio In to Sync Ref for Peripheral to Central direction
-    				if (sdu_interval_us > 0) {
-    					if (alternate_toggle_state == ALTERNATE_TOGGLE_STATE_IDLE) {
-
-    						// note: for Peripheral to Central, the SDU Sync Ref matches the ISO TX Timestamp
-
-    						// calculate next audio in time such that:
-    						// - it's in the future
-    						// - audio_in_us + presentatioon time = sdu_sync_ref
-    						uint32_t audio_in_us = iso_tx_us - PRESENTATION_TIME_US;
-    						while (audio_in_us < (bluetooth_time_us + 10000)) {
-    							audio_in_us += sdu_interval_us;
-    						}
-
-    						// convert into local time reference
-    						const uint32_t rise_us = local_time_us + (audio_in_us - bluetooth_time_us);
-    						const uint32_t fall_us = rise_us + PRESENTATION_TIME_US;
-
-    						//	LOG_INF("bt %u, tx %u, audio in %u // sdu %u // now %u, rise %u",
-							//		bluetooth_time_us, iso_tx_us, audio_in_us,
-							//		sdu_interval_us,
-							//		local_time_us, rise_us);
-
-    						alternate_toggle_setup(rise_us, fall_us);
-    					}
-    				}
-#endif
-    			}
-    		}
-     	}
-#endif
-
+		buf = k_fifo_get(&rx_queue, K_FOREVER);
 		err = h4_send(buf);
 		if (err) {
 			LOG_ERR("Failed to send");