Proj-2014-2015-ESP8266/SRS

The document provides a template of the Software Requirements Specification (SRS). It is inspired of the IEEE/ANSI 830-1998 Standard.

Read first:

• http://www.cs.st-andrews.ac.uk/~ifs/Books/SE9/Presentations/PPTX/Ch4.pptx
• http://en.wikipedia.org/wiki/Software_requirements_specification
• IEEE Recommended Practice for Software Requirements Specifications IEEE Std 830-1998

Document History

	Version	Date	Authors	Description	Validator	Validation Date
	0.1.0	Jan 26 2015	Luc Libralesso - Olivier Soldano	TBC	TBC	TBC

1. Introduction

1.1 Purpose of the requirements document

The purpose of the project is to implement a toolchain that allows to write programs in a high level language (in this case python2.7), compile it into a low level language like C or C++ and compile it with an other toolchain for running this program on an arduino-like board.

1.2 Scope of the product

For a given arduino-like board, we want to generate C++ code from given python code that compiles in a given toolchain.

1.3 Definitions, acronyms and abbreviations

• Toolchain : set of tools that compiles a program for a given processor
• C,C++,python: Programming languages
• high level language : a language alike natural language
• low level language : a language alike assembly language
• IoT : Internet of Things

2. General description

2.1 Product perspective

This project use the python2.7 language specifications for it's inputs. It's output generate executables for Xtensa processors by means of the Xtensa toolchain.

2.2 Product functions

Functions :

• Compile Python files to C++ files
• Run executables on some processors (like ESP8266)

2.3 User characteristics

Users need to be able to :

• Use command line
• Compile Xtensa and others toolchains
• Connect their device to the USB port of their PC for UART

2.4 General constraints

• Hardware limitations : On some devices like ESP8266, memory heap is limited so, we need to have a compiler that makes small executables.
• Parallel operations : For the wifi feature, we need to have a real time system. Consequently, it's difficult to implement a garbage collector.

2.5 Assumptions and dependencies

We assume that :

• The user has a serial cable to bind his PC and his card.

3.Specific requirements, covering functional, non-functional and interface requirements

• maintenance : scaleable code
• robust : each command is correctly executed
• useable : easy to use and get started with
• ethic : free software and well crafted code (PEP8 tests for instance)
• space : the memory heap limited on ESP8266 so we need a small executable file

3.1 Requirement X.Y.Z (in Structured Natural Language)

Function: Provide a way to compile python to C++ and C++ to assembly language for a specific chip.

Description: Our project consists to use a previous work at Polytech'Grenoble to implement a python-C++ translator and use the Xtensa toolchain to compile programs on ESP8266.

Inputs: Source program in python2.7 and a given microchip (here ESP8266)

Source: a compiler python-C++ (Shedskin) with a toolchain (Xtensa)

Outputs: a program uploaded on the card compiled from the input source program.

Destination: All the people who is interested in the IoT.

Action: Compiles Python to C++ and compile C++ to assembly language for a specific chip.

Non functional requirements:

• maintenance : scaleable code
• robust : each command is correctly executed
• useable : easy to use and get started with
• ethic : free software and well crafted code (PEP8 tests for instance)
• space : the memory heap limited on ESP8266 so we need a small executable file

Pre-condition:

• the use must have the required hardware (card, cable) and software (Xtensa installed)

Post-condition:

• The user gets a compiled version of his program on his chip.

Side-effects:

4. Product evolution

With this project, we have a way to compile high level languages to C, C++.

For further applications, we can compile others languages like lua, OCaml ...

We can also port another cards and others features.