Difference between revisions of "Tiny-BCU"

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(Created page with "= Idea = * BCU without ready-to-use KNX Transceiver like OnSemi, Siemens or Elmos * Small µC that reads/writes the bits to KNX bus and * "emulates" a reduced KNX TPUART BCU...")
 
 
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* Small µC that reads/writes the bits to KNX bus and
 
* Small µC that reads/writes the bits to KNX bus and
 
* "emulates" a reduced KNX TPUART BCU protocol
 
* "emulates" a reduced KNX TPUART BCU protocol
 +
 +
= Benefits =
 +
 +
* No dependency to onsemi & co: OnSemi had several times delivery difficulties; Elmos can not be ordered when you're private person, Siemens is not cheap
 +
* better handling wrt. bus powered supply
 +
* easier to build, due to no QFN package
 +
* Parts typically all available at german distributeros/electronic shops
 +
* possibly different and thus easier communication protocol (I2C?)
 +
* possibly more cpu cycles for the sketch due to caching on TinyBCU controller?!
 +
 +
= Cons =
 +
 +
* not that tiny as MicroBCU due to more parts on PCB
 +
* possibly not significant cheaper than traditional BCU
  
 
= Requirements =
 
= Requirements =
  
* Transceiver-Part: something to read/write the bits physically from/to KNX bus  
+
* Transceiver-Part: something to read/write the bits physically from/to KNX bus; simple analog circuit for extracting/inserting the bits from/to bus.
* Controller-Part: something that can interpret the bits from transceiver and make it BCU-style readable + write the bits of a telegram to the transceiver
+
* Controller-Part: something that can interpret the bits from transceiver-part and make it BCU-style readable + write the bits of a telegram to the transceiver-part
 
* Supply-Part: voltage and current from bus: at least 3.3V and 5V with about >=50mA, without creating interferrences on the BUS
 
* Supply-Part: voltage and current from bus: at least 3.3V and 5V with about >=50mA, without creating interferrences on the BUS
  

Latest revision as of 14:51, 16 March 2018

Idea

  • BCU without ready-to-use KNX Transceiver like OnSemi, Siemens or Elmos
  • Small µC that reads/writes the bits to KNX bus and
  • "emulates" a reduced KNX TPUART BCU protocol

Benefits

  • No dependency to onsemi & co: OnSemi had several times delivery difficulties; Elmos can not be ordered when you're private person, Siemens is not cheap
  • better handling wrt. bus powered supply
  • easier to build, due to no QFN package
  • Parts typically all available at german distributeros/electronic shops
  • possibly different and thus easier communication protocol (I2C?)
  • possibly more cpu cycles for the sketch due to caching on TinyBCU controller?!

Cons

  • not that tiny as MicroBCU due to more parts on PCB
  • possibly not significant cheaper than traditional BCU

Requirements

  • Transceiver-Part: something to read/write the bits physically from/to KNX bus; simple analog circuit for extracting/inserting the bits from/to bus.
  • Controller-Part: something that can interpret the bits from transceiver-part and make it BCU-style readable + write the bits of a telegram to the transceiver-part
  • Supply-Part: voltage and current from bus: at least 3.3V and 5V with about >=50mA, without creating interferrences on the BUS

Transceiver-Part

See: https://github.com/selfbus/hardware-incubation/tree/master/module/UPModule

Supply-Part

See: https://github.com/selfbus/hardware-incubation/tree/master/module/UPModule For instance one can also use the "Polulu" step-down modules to create 3.3V and 5V from up to 40V input. The are multiple candidates available, f.i. from TI

Controller-Part

Something like the Attiny85.

Features:

Open questions: How to debug? Maybe develop with Arduino UNO and then port to attiny?

SW: See: https://github.com/selfbus/software-arm-lib/tree/master/sblib/inc/sblib/eib