sdc_hci_cmd_vs_iso_read_tx_timestamp()

uint8_t sdc_hci_cmd_vs_iso_read_tx_timestamp	(	const sdc_hci_cmd_vs_iso_read_tx_timestamp_t *	p_params,
		sdc_hci_cmd_vs_iso_read_tx_timestamp_return_t *	p_return )

#include <softdevice_controller/include/sdc_hci_vs.h>

Iso Read Tx Timestamp.

The controller operates on a timeline that determines when an SDU provided by the host is scheduled for transmission. This command is used to return the tx_time_stamp and packet_sequence_number that determines where on this timeline the previously provided SDU was scheduled. The packet_sequence_number is a quantization of the tx_time_stamp. The SDU is provided for transmission on a CIS or BIS as identified by the conn_handle parameter on the Central or Peripheral.

This command is made to simplify sending SDUs on different ISO streams in the same ISO event.

The returned timestamp is set to start of the CIG or BIG event in which the first PDU containing the SDU is scheduled for transmission. The returned timestamp may be set to a value in the past or into the future depending on how the application has previously provided SDUs to the controller.

If the application provided the previous SDU with a timestamp in the past, the returned timestamp still represents the scheduled transmission time. That is, the timestamp cannot be used to know when the SDU was actually sent.

The returned timestamp can be used to make the application provide SDUs to the controller right before they are sent on air. The returned value can also be used to synchronize the transmitter and receiver.

The following equations can be used to find the relation between timestamps on the transmitter and receiver: CIS_reference_anchor_point = tx_time_stamp + CIG_Sync_Delay - CIS_Sync_Delay BIG_reference_anchor_point = tx_time_stamp + PTO * ISO_Interval See also Core Specification, Vol 6, Part G, Section 3.

If the Host issues this command with a connection handle that does not exist, or the connection handle is not associated with a CIS or BIS, the Controller shall return the error code Unknown Connection Identifier (0x02).

If the Host issues this command on an existing connection handle for a CIS or BIS where a ISO data path is not enabled, the Controller shall return the error code Command Disallowed (0x0C).

Event(s) generated (unless masked away):

When the HCI_LE_Read_ISO_TX_Sync command has completed, an HCI_Command_Complete event shall be generated.

Parameters

[in]	p_params	Input parameters.
[out]	p_return	Extra return parameters.

Return values

0	if success.

Returns

Returns value between 0x01-0xFF in case of error. See Vol 2, Part D, Error for a list of error codes and descriptions.