swv

Nodejs library that can parse SWV trace output.

How to install SWV

Prerequisite is nodejs.

$ git clone https://github.com/phryniszak/swv.git
$ cd swv
$ npm install

It installs only one additional library minimist, needed to parse app arguments.

Parse file

Create trace file using openocd:

tpiu config internal itm.fifo uart off 170000000

and trace output:

$ node index.js --path itm.fifo

Connect to pipe

Reading via a named pipe works well on POSIX machines; e.g. Linux or macOS, but not Windows.

$ mkfifo /tmp/itm.fifo
$ node index.js --path /tmp/itm.fifo --type pipe

This will create a named pipe: /tmp/itm.fifo. Then start openocd directing output to pipe:

tpiu config internal /tmp/itm.fifo uart off 170000000

Connect to socket

Start openocd with redirecting trace output to TCP server

tpiu config internal :3344 uart off 170000000

And start app passing port number:

node index.js --port 3344 --type socket

Connect to serial port

TODO:

Merging traces

Library attempts to merge trace packet in logical chunks, but in some cases, like trace without timestamp this functionality may fail. Passing --nomerge forces library to disable merging.

Example app output

{
  _: [],
  port: 3344,
  type: 'socket',
  path: 'itm.fifo',
  host: 'localhost'
}
connected
TraceITMEvent {
  _desc: 'itm',
  _timestamp: 1480586,
  _port: 1,
  _data: 15,
  _width: 1
}
TraceITMEvent {
  _desc: 'itm',
  _timestamp: 1480638,
  _port: 2,
  _data: 15,
  _width: 1
}

ACKNOWLEDGMENTS

ITM decoder is taken from pyocd and converted from python to js with few modification. Some inspiration also from Cortex Debug