Kristil – Smart House – Technical Notes

This page is just a place to put random technical notes relating to the system originally installed by Smart House and later re-branded as Kristil. Most of this information relates to the system as installed between 1998 and about 2005. Much of this information is still valid.

Smart Switch

Early version switches used a OTP (one time programmable) MC68HC11E9CFN2 micro. This required a new chip installed to update the firmware. Later versions used the MC68HC11F1 with external FLASH and RAM memory; allowing firmware upgrades of

The switch configuration is stored in EEPROM memory within the HC11. Active status and control variables are in RAM.

  • Hold all 4 buttons and apply power to restore EEPROM default settings.


This example network message ( 00-07-10-C4-02-6C-0E-57-00 ) is smart-switch #10 sending a 7 byte broadcast message to all on the network, that writes data 0E to address 6C0E (or 0E6C). This is the current outside light level being sent to all switches on the network and repeats about every minute.

  • Packets must have the following format: T B F D . . . . . D C C
  • T = to address (00 = broadcast, FF = master #1, FE = none yet)
  • B = byte count (inc. T, B, F & D, but not C C)
  • F = from address
  • D = data bytes (12 bytes maximum)
  • C = 16 bit Check Sum (calculated as packets are transmitted and received)

Messages – Commands

Command – Address – Rx/Tx – Data bytes – Action/Comments


  • B0    NODE    RX    3    request send data block
  • C1    NODE    RX    ??    accept data block (inc address etc)
  • C2    NODE    RX    3    bit set, address, mask
  • C3    NODE    RX    3    bit clear, address, mask
  • C4    NODE    RX    3    byte save, address, mask
  • C5    NODE    RX    2    run code from address ??
  • C6    NODE    RX    3    turn circuit on
  • C7    NODE    RX    3    turn circuit off


  • D0    NODE    RX    0    request status
  • D2    NODE    TX    4    accept data (reply to D0)
  • D3    NODE    TX    8    accept data (reply to D1)


  • E0    NODE    RX    8    accept this full address ??
  • E1    NODE    RX    1    accept this node address ??


  • F0    00/NODE    RX    2    go quiet for ???? cycles
  • F1    NODE    RX    0    take possession of network token
  • F2    NODE    RX    0    surrender token

Sample messages recorded

00-07-10-C4-02-6C-35-7E-00 : light level ??