Timestamp Inserter (`timestamp_inserter`)

Inserts timestamps before sample opcode messages. Can be configured to insert a timestamp before every sample opcode, or only when requested.

Design

Passes all opcode messages received on the input port to the output port. When a Sample opcode message is received, a timestamp is optionally output via a Time opcode message before the Sample opcode message is passed onto the output.

On reception of a Sample opcode, if the property continuous_mode is true, a timestamp is generated and inserted as a Time opcode before the Sample opcode message. If continuous_mode is false, the timestamp is only generated and inserted if the property timestamp_pending is true.

When the worker inserts a Time opcode, it clears the timestamp_pending property to false. This also indicates that a timestamp insertion action has been been completed.

Thus if both continuous_mode and timestamp_pending are false, no timestamp insertion action shall occur, and the component just passes data through unchanged.

A block diagram of the component is as follows:-

Interface

<?xml version="1.0"?>
<componentspec>
  <property name="continuous_mode" type="bool" writable="true" default="true"
    description="Enables the insertion of a timestamp before each data message."/>
  <property name="timestamp_pending" type="bool" writable="true" volatile="true" default="true"
    description="Signals that a timestamp is to be inserted before a data message."/>
  <property name="leap_seconds" type="uchar" writable="true" default="0"
    description="Current number of leap seconds between UTC and GPS time."/>
  <property name="port_width" type="uchar" initial="true" writable="false" default="16"
    description="Defines the input data width in bits."/>
  <port name="input" producer="false" numberofopcodes="6" defaultbuffersize="16384"/>
  <port name="output" producer="true" numberofopcodes="6" defaultbuffersize="16384"/>
</componentspec>

Properties

continuous_mode: Enables the insertion of a timestamp before each data message. When true, timestamps are inserted before every sample opcode in the data stream. When false, single timestamps are inserted as governed by the timestamp_pending property.
- Type: bool
- Access:
  - Parameter: False
  - Writable: True
  - Initial: False
  - Volatile: False
- Default value: true
timestamp_pending: Signals that a timestamp is to be inserted before a data message. When continuous_mode is false, setting timestamp_pending to true triggers a timestamp to be sent before the next sample opcode. The worker will set timestamp_pending to false when it has completed the insertion of the timestamp. When continuous_mode is true, the timestamp_pending value is ignored and the worker will set it to false.
- Type: bool
- Access:
  - Parameter: False
  - Writable: True
  - Initial: False
  - Volatile: True
- Default value: true
leap_seconds: Current number of leap seconds between UTC and GPS time.
- Type: uchar
- Access:
  - Parameter: False
  - Writable: True
  - Initial: False
  - Volatile: False
- Default value: 0
port_width: Defines the input data width in bits.
- Type: uchar
- Access:
  - Parameter: False
  - Writable: False
  - Initial: True
  - Volatile: False
- Default value: 16

Ports

Inputs:

input: Primary input samples port.
- Protocol: None
- Optional: False

Outputs:

output: Primary output samples port.
- Protocol: None
- Optional: False

Implementations

timestamp_inserter (HDL)
timestamp_inserter (RCC)

Example Application

<?xml version="1.0"?>
<application done="file_write">
  <instance component="ocpi.core.file_read" connect="timestamp_inserter">
    <property name="filename" value="input.bin"/>
  </instance>
  <instance component="ocpi.comp.sdr.interface.timestamp_inserter" connect="file_write">
    <property name="port_width" value="16"/>
    <property name="continuous_mode" value="true"/>
    <property name="timestamp_pending" value="true"/>
  </instance>
  <instance component="ocpi.core.file_write">
    <property name="filename" value="output.bin"/>
  </instance>
</application>

Dependencies

The dependencies to other elements in OpenCPI are:

HDL OpenCPI dependencies:

Time-server.

Time-client.

SDR Utilities Library

RCC OpenCPI dependencies:

components/util/common/opcodes.hh

There is also a dependency on:

HDL specific dependencies:

ieee.std_logic_1164

ieee.numeric_std

ieee.math_real

RCC specific dependencies:

<chrono>

Limitations

The limitations of timestamp_inserter are:

Multiple triggering of the timestamp_pending property will result in only one timestamp being inserted before an input message.

Whilst the component is “protocol-less”, it is assumed it will be used with one of the the timed sample protocols.

Testing

Tested platforms: None

Component testing not completed.

Timestamp Inserter (timestamp_inserter)