Update README; add link to energytrace paper

# msp430-etv – MSP430 EnergyTrace Visualizer

msp430-etv is a wrapper around

[energytrace-util](https://github.com/derf/energytrace-util) to

simplify aggregation, visualization and basic analysis of EnergyTrace

measurements.

msp430-etv performs, visualizes and analyzes energy measurements performed

on TI MSP430 Launchpads using the on-board EnergyTrace circuit.

Measumerents can be taken directly or loaded from energytrace-util output.

Data belonging to startup code whose power consumption is not of interest can

be skipped.

It uses [energytrace-util](https://github.com/derf/energytrace-util) to start

and stop measurements using the proprietary TI MSP430 library. Measurements can

be analyzed directly or saved to a file for later analysis as well as

processing by other tools.

msp430-etv supports plotting the power consumption (calculated from voltage and

current data) and writing mean voltage, current, and power as well as total

energy for a given measurement to stdout.

Analysis options include

* plots showing voltage, current, or power over time,

* data partitioning and statistics using a power threshold, and

* changepoint detectiong using the PELT algorithm.

See `bin/msp430-etv --help` for usage details. See [Automatic Energy Model

Generation with MSP430

EnergyTrace](https://ess.cs.uos.de/static/papers/Friesel-2021-CPSIoTBench.pdf)

for accuracy figures and some odds and ends.

## File Format

EnergyTrace performs measurements in intervals of about 270 µs. Each line

contains data for one measurement interval. Measurement data consists of for

readings:

* Timestamps (µs) since start of the measurement,

* Mean current (nA) over the last ten to thousand intervals,

* Mean voltage (mV) with details unknown, and

* Cumulative energy (nJ) since start of the measurement.

Note that the EnergyTrace hardware and firmware only measures time, voltage,

and energy. Current readings are calculated by the MSP430 client library. Power

readings are calculated from timestamps and energy readings by msp430-etv.

## Dependencies

* [energytrace-util](https://github.com/derf/energytrace-util)

  and libmsp430.so

* Python 3 with matplotlib and numpy

* Python 3, numpy

* Taking measurements: [energytrace-util](https://github.com/derf/energytrace-util) and libmsp430.so

* Plots: python3-matplotlib

* Changepoint detection: python3-ruptures