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SDC I/O Hat

Purchase an SDC I/O Hat Here

This PCB connects directly to your Pi and provides the following features:

  • A means to safely connect the 5v serial lines from the Arduino Mega
  • On board power supply
  • Ignition feed input for shutdown control (currently requires readily available separate shutdown delay board)
  • GPIO Inputs for rotary encoder support and/or momentary buttons
  • Optional Canbus support, using for a multi processor implementation or to allow other third party devices to contribute daa items to the SDC display

Pictured below is a canbus version:

Connections

Top connections (left to right):

  • Ground
  • +12v
  • Ignition +12v (when key is on)
  • ECU ground
  • ECU Tx (connect the pin labelled Tx on the Mega to this input)
  • Pi Tx (connect the pin labelled Rx on the Mega to this output)

Bottom Connections:

  • Jumper for 120ohm Canbus termination resistor
  • CAN Hi
  • CAN Lo
  • CAN Hi
  • CAN Lo

2 sets of can lines allow the bus to be easily passed on to the next device.

Left hand row of pins (top to bottom):

  • GPIO16 (CK)
  • GPIO17 (DT)
  • GPIO18 (SW)
  • 3v3
  • GND (The above 5 pins are the defaults be used for a rotary encoder if you wish to connect one)
  • GPIO19
  • GND
  • GPIO20
  • GND
  • GPIO21
  • GND
  • 5V
  • GND
  • 3V3
  • SDA
  • SDL (Above pins can be used to connect an I2C RTC)

Note the impage above is a CANBUS pre-production PCB so it may not exactly match the description above. However, the description is accurate for the released product.

Ignition Input

The SDC.ini file contains a default configuration for GPIO13 to control the shutdown of the device, using the ignition input as the shutdown trigger. In order for this to work, you must enable the configuration by removing the semicolon from the [buttons] entry (remove from the last line):

[buttons]
;13 is the default shutdown button used with the SDC IO hat.
;Enable the line below and check the help to enable controlled shutdown.
;You must have an ignition feed connected to the board otherwise the system
;will shut down as soon as it boots up.
;shutdownbutton=13,shutdown

To enable this you must satisfy the following preconditions:

  • A delayed power off board must be installed and working
  • You must have an ignition feed connected to the input on the I/O Hat

If you do not connect the ignition feed but you enable this configuration, then the system will shut down immediately because the floating input will be pulled down internally thus triggering the shutdown action immediately.