DASH7 Webinar: Working With Open Tag For Mode 2

OpenTag Mode 2 Webinar

JP Norair
12 January 2011

jpnorair@indigresso.com

Copyright © DASH7 Alliance

Webinar Agenda

‣ Stuff you need to know
‣ Stuff you probably want to know
‣ Stuff you might not care about,
that I’m going to tell you anyway


About the Author

• JP Norair
‣ jpnorair@indigresso.com
‣ skype: jpnorair

• Chair of DASH7 Technology Working Group

• Chief architect of Mode 2 spec

• Leader of OpenTag project
(Open source DASH7 ﬁrmware stack)

• Developer of products using DASH7 and
related technologies

• Lover of all-night debug sessions


How You Can Help OpenTag

• Sponsor a port to your platform
‣ Helps fund general development
‣ Fast path to ofﬁcial platform support
‣ I will talk about your stuff all the time DASH7 Alliance Annual Meeting
31 Jan - 2 Feb 2011: San Diego, CA
• Join DASH7 Alliance and support Mode 2 (Contact pat@dash7.org)
(the spec that OpenTag implements)
I will be presenting a 3 hour demo and
• Write your own code, and submit it to the developer seminar on OpenTag
repository (I will make a branch for you)

• Get involved in the Beta Testing

• Send me energy drinks:
2025 Broderick St. #08
San Francisco, CA 94115


Webinar Agenda

‣ Stuff you need to know History & Timelines
‣ Stuff you probably want to know Feature Overview

‣ Stuff you might not care about, Architecture Overview
that I’m going to tell you anyway Getting OpenTag


OpenTag Design Philosophy

Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere.

– Colin Chapman, founder of Lotus Cars


OpenTag Has Been Revised Many Times
Development of OpenTag Mode 2 has been in parallel to the Mode 2 spec development itself

2008 2009 2010 2011
1st Half 2nd Half 1st Half 2nd Half 1st Half 2nd Half 1st Half 2nd Half

Early test OpenTag DASH7 Mode 2 OpenTag
versions Mode 1 Alphas Spec Drafted Mode 2 Betas

OpenTag
Mode 1 Betas Begin total rewrite of Mode 2 Spec FCD,
OpenTag for Mode 2 OpenTag 1.x

OpenTag for Mode 1 was abandoned, in part due to lack of any Mode 1 SoC’s,
but also because developing for Mode 1 is too painful to be practical.

DASH7 Mode 2 is a 2nd Generation WSN/IoT/RFID Technology

433 MHz band
8 channels
Optimized for
Optimized for
Low Latency
Micro Power
(Bursty Data)

Mode 2
Universal Adaptive Data Rate
Interoperability 28 - 200 kbps

Very Fast Compact Stack
Multicast typ. 16KB


Near-Term Alpha and Beta Schedule

Nightly Alpha/Beta builds will be available on the sourceforge code repository

Beta 1
Alpha
Alpha
Beta 0
Beta 1

• Alpha Milestone: The core code works • Beta 2 Milestone: Passes regulatory testing and
attains DASH7 compliance/certiﬁcation
• Beta 0 Milestone: A feature subset runs on HW
• 1.0: First Ofﬁcial Release
• Beta 1 Milestone: All 1.0 features run on HW


A Great Effort to Keep the Codebase Small & Light
Design elegance leads to reliability and low cost

Small Size Less Code Less to go wrong

Lower HW requirements Lower Cost

Comm Stack ROM/ Open Multihop Multicast File- Crypto IPv6 Scriptable Shellable Userspace
RAM KB Source Support Queries system Security Programmable

OpenTag DASH7 Mode 2 16 / 1 • optional • • • optional • • •

Contiki Proprietary 40 / 2 • • • • •

ZigBee ZigBee 115 / 4 • • •

ZigBee PRO ZigBee 136 / 4 • • •


OpenTag Can Run on Damn-Near Anything
95%+ of Code is Platform-Agnostic ANSI C

OS Support Known Memory Support Known Core Support Known Transceivers [SoC]

MSP430 (Confirmed)
FLASH CC11xx [CC430]
“Bare Metal” ARM (Confirmed)
(No OS) EEPROM ADF7023 [ADµCRF101]
x86 (Confirmed)
Most RTOS’s DRAM SX1212 [SX1282]
AVR (Likely)
POSIX Shell SRAM SX1231
(in simulation) CoolRISC (Likely)
FRAM Si442x [Si10xx]
8051 (Likely)


List of Main OpenTag Features
Or: “What you get for your hard-earned kilobyte”

Module Feature Availability Status Approx. KB*
C-based API Beta 0 Compile-time option 1
API
Serial Console API-shell Beta 0 Compile-time option 0.1
Event-Based MAC Task Engine Beta 0 Mandatory 2
Wake-on Radio Sequencing Beta 0 Runtime option 0.06
MAC
Automatic Beacon Sequencing Beta 0 Runtime option 0.03
Real-Time Event Scheduling Beta 1 Compile/Runtime option 0.2
Base Mode 2 Protocol Beta 0 Mandatory 2
Protocol
Extended Mode 2 Protocol(s) Beta 1 Compile-time option 2+
Radio Full Mode 2 PHY/MAC Support Beta 0 Mandatory 1
Streaming CRC Engine Beta 0 Mandatory 0.1
CRC
SW-based CRC Calculator Beta 0 Compile-time option 0.5**
Streaming Codec Framework Beta 0 Mandatory 0.1
SW-based FEC Codec Beta 0 Compile-time option 1
Encoder
SW-based PN9 Codec Beta 0 Compile-time option 0.1**
HW-based Codec pass through Beta 0 Compile-time option 0.1
POSIX-like Virtual Filesystem Beta 0 Mandatory 1
FLASH Wear Leveling Beta 0/1 Compile-time option 2
Veelite
Data Storage Encryption Beta 1 Runtime option 0.05
File Heap Beta 0 Compile-time option 4+†

*Compiled on CC430 with mixed speed/size optimization **Not required for CC430 build †User ﬁle storage allocation Total: 16.8 KB

How to Download Nightly OpenTag Builds
If you are a developer, you probably already know this routine

1.Go to the OpenTag sourceforge page
http://sourceforge.net/projects/opentag

2.Browse Code repository http://sourceforge.net/projects/opentag

— OR —

1.Download any Git client
“git” is the original (POSIX command line)

2.Go to (or create) an empty directory

3.Clone my repository to your directory. For classic git, see below.
$ git clone git://opentag.git.sourceforge.net/gitroot/opentag/OpenTag_M2


Webinar Agenda

‣ Stuff you probably want to know The world’s easiest tag code
‣ Stuff you might not care about, Exploring the API
that I’m going to tell you anyway Conﬁguring the Build


The World’s Easiest Tag Code

• Yes: this is simpliﬁed pseudocode, but the concept is
accurate and even workable for simple “Tag” devices.

• One extra layer of complexity is to determine the longest
runtime of my_program():
‣ Let’s say it is 5 ms
‣ Add a condition to skip my_program() if ot_run()
returns 5 ms or less

• If you use an RTOS with a “system tick” period of 5 ms,
then integration with the RTOS follows the same idea.

• As we will see later, my_program()can actually feed
information back to OpenTag in a variety of ways.


OpenTag API: Shock & Awe
OpenTag is like a shell and possibly an OS, too.

OpenTag can be controlled directly,
with C, or indirectly, over a message
pipe. Any kind of data interface will do MAC
(often it is a serial wire). Control
Veelite:
(Virtual EEPROM Lite)
C API User
LLDP: Data
Message Pipe (Low Level Directive POSIX-like ﬁlesystem
(optional)
Protocol) for Mode 2 Data.

Short messaging directives that
Script User
can be used in combination
Engine Program
to do large tasks Protocol
(optional) (optional)
Layer


OpenTag API: Shock & Awe
Running stored programs is the same as running API directives

This is the feedback loop that allows users to script and store
MAC
custom routines. This can be dangerous! By default it is disabled.
Control
On the plus side, it allows for users to load complex “stored
procedures” or other sorts of programs, such as a PPP daemon.
Veelite:
Programs are stored in Veelite, they run in userspace, and they Lite)
(Virtual EEPROM
C API require authentication to LLDP:
run. They cannot affect data that is not
User
accessible to the(Low (i.e. root-only data)
user Level Directive Data
Message Pipe POSIX-like ﬁlesystem
(optional)
Protocol) for Mode 2 Data.

Short messaging directives that
Script User
can be used in combination
Engine Program
to do large tasks Protocol
(optional) (optional)
Layer


OpenTag API: A Practical Perspective
Writing Data to a Mode 2 Data Element via the Messaging API (LLDP)

• Does this make any sense to you?
(Probably not)

• This code changes the value of the Mode 2 Sleep
Scan Sequence UDB, which in turn changes the
way the device monitors channels for activity.

• The otapi_set...() and get functions are
accessing a message pipe.

• This kind of code would generally never run on a
tiny embedded device. It is meant to run on the
thing that is connected to your tiny device.
‣ If you are a developer, this means the PC that is
connected to your dev kit with a wire.
‣ If you are a system integrator, this means the piece
of edgeware that is driving your stuff.


OpenTag API: A Practical Perspective
Writing Data to a Mode 2 Data Element via the C API

• Does this make any sense to you?
(It probably does, if you’ve seen stdio.h)

• This code does the same job as the last code

• The UDB_open_su() opens the UDB as the
root user, which guarantees write access.

• This kind of code is used all over the place
inside OpenTag. You could use it in
my_program() just as easily.
‣ The UDB contains all sorts of conﬁguration
registers that control OpenTag behavior.
‣ The UDB contains data elements, like location Still confused? Don’t worry too much:
lists and sensor data lists. It won’t be long before there are
libraries of cookbook-type OpenTag
functions on SourceForge.


Conﬁguring a Build
The secret to OpenTag’s portability This is an OpenTag Feature.
It only compiles if you want
to use streaming CRC
• You don’t need to understand this code, it is just
an example of Compile-Time options

• Without touching any of the code (apart from
the conﬁg headers), you can dramatically
change the scope of features available to your
build of OpenTag. It is even address size and
endian agnostic at the C code level.

This is a Platform Feature.
It only compiles if your HW
cannot encode PN9 per the
Mode 2 Spec


Configuring a Build
Configuration File Examples (CC430 in this example)

/OTlib/OT_config.h /Platforms/CC430/platform_config_CC430.h
Software Features for Any Platform Features (or Limitations) of the Hardware

Some of these lists go on for
hundreds of lines and allow
deep-drilling optimization

Wakeup!
(The code example part is over)


Webinar Agenda

‣ Stuff you probably want to know
‣ Stuff you might not care about, Porting OpenTag to New HW
that I’m going to tell you anyway Running in Simulation
Pending Releases


Porting OpenTag to New HW
Stuff you don’t really need to touch

• The OTlib directory is all ANSI C, and has hooks
that allow it to be as close to 100% platform
agnostic as a C program can be.

• You will need to add your Platform Name to
platform_support.h (pretty easy)

• You will need to add your Platform header to
platform_conﬁg.h (pretty easy)


Porting OpenTag to New HW
Stuff you need to create

• You WILL need to write some drivers and
headers for anything that interacts directly
with the platform.

• Create a new directory in /Platforms/

• A lot of platforms are similar. Most of the
time I am able to copy the ﬁles from one
port to another, and modify them only
slightly.


Using the Simulator

• Since the code is portable and doesn’t hook
into hardware at the library level, it is pretty
easy to test compared to the traditional
embedded build-load-debug cycle.

• I have written a handful of test programs
- as simple as make & run

• On a modern PC I can go take a nap, and
when I come back, 100 billion test vectors
have run.
‣ This is orders of magnitude more
transactions than all WSN & active RFID
devices have been put through, combined,
to date.
I use a pleasant sea anemone
motif for my shell


What Each Release Entails

Alpha Beta 0 Beta 1 Beta 2

Beta 0 OTlib featureset Platform layer tested Beta 0/1 OTlib featureset Regulatory Testing
tested to exhaustion via thoroughly on CC430 tested to exhaustion via
Simulator Simulator, and HW
Work with DASH7 Alliance
to define Mode 2
Get Platform layer to run Port to ADµCRF101
Full-scale interoperability Certification process
just once on CC430 tests between CC430 and
ADµCRF101

By most accounts, Beta 2 will be a
deployable version.
Changes between Beta 2 and v1.0 should
just be configuration settings.

When this is all over, I will treat
myself to some ﬁne wine.


Questions & Comments


DASH7 Webinar: Working With Open Tag For Mode 2

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