Own Technology

HStack

A KNX protocol stack we wrote ourselves, from the bit on the twisted pair up to the application layer.

System B TP-1 twisted pair KNX Data Secure C source licence
Download the datasheet Talk to engineering

Written in house, registered in its own right

Every layer of HStack is Horizentis code, from the 104 microsecond bit timing on the twisted pair up to the application layer. KNX Association registered it as a stack of its own, under manufacturer ID 867.

Architecture

Every layer, all the way down

You write the application on top and adapt the porting layer at the bottom. Everything between them is HStack.

Your device application Written by you, on the stack API
Licensed as C source
Application layer / AIL Group objects, interface objects, function properties, KNX Data Secure
Transport layer Multicast and connection oriented communication
Network layer Individual and group addressing, hop count control
Data link layer Framing, parity, acknowledge, repetition, collision
Physical layer TP-1 bit timing in the microcontroller timers, 104 microsecond bit
Target porting layer Flash, timer and RTOS hooks, adapt to your board
onsemi NCN5110 transceiver Bit level line driver
KNX TP-1 bus
On the wire

The bottom layer, measured

A logic analyser on a live KNX line while HStack is running. Every burst is one telegram, read off the twisted pair and decoded field by field.

Logic analyser capture of KNX TP-1 traffic, taken while the stack was running.
At a glance

What the stack is

Device descriptor 07B0h System B, the profile ETS expects from a modern end device
Medium TP1-256 Twisted pair, standard and extended frames
Maximum APDU 69 octets, so long transfers finish in one telegram
Footprint 53 kB flash on the reference target, with security enabled
Target Cortex-M0+ STM32G0, certified on an STM32G0B0CET6
Security Data Secure Tool key, group keys and point to point keys
Delivery

Licensed as source code, not as a black box

You receive the code, not a compiled library. The KNX layer of your product stays readable, debuggable and maintainable by your own team for the whole life of the product.

The whole stack in C

Every KNX layer from the physical layer to the application interface layer, with the headers that form the application API.

The porting layer

Timers, flash, reset and the programming button and LED for the STM32G0, ready to move onto your own board.

A project that builds

The Keil MDK project used for the certification build, an example application and an example ETS product database.

Working together

How a project runs

  1. 1

    Hardware

    Build your board around the STM32G0 and the NCN5110, or start from our reference design.

  2. 2

    Port

    Adapt the target layer to your board. Keep the reference pin assignment and there is nothing to change.

  3. 3

    Declare

    Describe your group objects, parameters and interface objects once, and build the matching ETS product database.

  4. 4

    Apply

    Write your application against the stack API. The stack calls you when a group object is updated, and you call it when a value changes.

  5. 5

    Certify

    The stack is already registered, so your device certification covers your application and your hardware, not the protocol implementation.

Documentation

Datasheet and conformance statement

Both documents are published in English. The signed PICS and PIXIT forms filed with KNX Association are supplied with the licence.

Product datasheet PDF, 4 pages, English KNX conformance statement PDF, 3 pages, English

Registration 867/23232/26 covers the HStack protocol stack. A device built on HStack still needs its own KNX product certification, which covers its application program, its hardware and its ETS product database.

Building a KNX device?

Tell us what you are building and we will tell you what porting it would take. Licence terms are quoted per project.

Talk to us about licensing