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Introduction

The SDC I/O hat is used to provide power to your Raspberry Pi, normally in conjunction with a delayed shutdown module. It contains an on-board voltage regulator which is set to 5v, together with an ignition sense input to provide a signal to the Raspberry Pi that shutdown is required.

Connections

  • Connect a permanent battery ground to the “BAT GND” input

If you are using a delayed shutdown module:

  • Connect the power output of the delayed shutdown module (see the module’s instructions) to the “BAT 12V” input.
  • Connect a switched +12v to the “IGN” input. This should be direct from the ignition key circuit, not from the output of the delayed power module (but you can take a link wire from the power module’s SVCC input).

If you are not using a delayed shutdown module:

  • Connect a switched +12v to the “BAT 12V” input (i.e. switched via the ignition key).
  • Leave the IGN input disconnected
  • Do not enable data logging in SDC.
  • Make sure the [button] setting for button 13 has not been enabled (this is the default state, so if you have never enabled it then you’re fine).

And in both cases you must also:

  • Connect a ground from the microcontroller to the “ECUGND” input.
  • Connect the microcontroller’s secondary serial TX pin to the input labelled ECU TX.
  • Connect the microcontroller’s secondary serial RX pin to the output labelled PI TX.
  • Set the JP1 link to either STM/Teensy or Mega according to which microcontroller you have. If you are not sure what you have, then please check with your supplier.

Make sure you have moved the jumper on JP1 to the correct place, as this controls the voltage that the Pi will see on its serial connection. For Mega, put the jumper so that it joins the middle pin to the pin labelled ‘Mega’. For STM32 or Teensy, or any other device that has 3.3v electronics, set the jumper so it joins the middle pin to the pin labelled ‘STM/Tnsy’. Do not guess this setting; you may damage the Pi.

Make sure you have fuses in the +12v circuit somewhere. Location is dependent upon whether you have a delayed shutdown module in the circuit or not.