From 7387259f763d8f1436114c15b51a35522148e3f5 Mon Sep 17 00:00:00 2001 From: Emilio Perez Date: Fri, 16 Feb 2024 10:44:55 +0000 Subject: [PATCH] Add documentation about PCAP start timestamp --- config_d/registers | 2 ++ docs/capture.rst | 25 +++++++++++++++++-------- 2 files changed, 19 insertions(+), 8 deletions(-) diff --git a/config_d/registers b/config_d/registers index 25d51ae8..82534e7c 100755 --- a/config_d/registers +++ b/config_d/registers @@ -41,7 +41,9 @@ BLOCKS_COMPAT_VERSION = 0 PCAP_WRITE 9 # Hardware timestamps + # This starts at unix epoch (UTC) PCAP_TS_SEC 10 + # Ticks since PCAP_TS_SEC was updated PCAP_TS_TICKS 11 # Position capture control diff --git a/docs/capture.rst b/docs/capture.rst index 2f148cdd..fe9dfdf3 100644 --- a/docs/capture.rst +++ b/docs/capture.rst @@ -136,14 +136,23 @@ Data Header At the beginning of each experiment the following information is sent: -=============== ================================================================ -arm_time UTC Timestamp sampled in correspondence of the ARM command -missed Number of samples missed by late data port connection. -process Data processing option: Scaled, Unscaled, or Raw. -format Data delivery formatting: ASCII, Base64, Framed, or Unframed. -sample_bytes Number of bytes in one sample unless ``format`` is ``ASCII``. -fields Information about each captured field. -=============== ================================================================ +================= ============================================================== +arm_time System timestamp when ARM command was sent +start_time Timestamp of when PCAP became both armed and enabled +hw_time_offset_ns Offset in ns from hardware timestamp to captured system time, + only present when hardware time source is used. +missed Number of samples missed by late data port connection. +process Data processing option: Scaled, Unscaled, or Raw. +format Data delivery formatting: ASCII, Base64, Framed, or Unframed. +sample_bytes Number of bytes in one sample unless ``format`` is ``ASCII``. +fields Information about each captured field. +================= ============================================================== + +All timestamps are unix time. + +``start_time`` will be a hardware timestamp if a hardware time source which +produces non-zero timestamps is selected, otherwise, it will be a system +timestamp saved by the driver. For each field the following information is sent: