Monthly Archives: April 2013

RasPiComm+

Here is a quick update on the RasPiComm+ status. We are currently working hard on the Raspberry Pi drivers and hope to get the RasPiComm+ out there in Q3.

RasPiComm Plus

RasPiComm Plus mounted on Raspberry Pi with GSM and 16 isolated I/O extensions

The board itself is a 56x74mm 4-layer board, most components are mounted on the bottom. The top-side only features 4 edge-board connectors for the modules, power LEDs and two JTAG debugging/programming headers for the Cortex M3/M4F and the Altera MAX V CLPD.

We currently have 6 RasPiComm+ modules which we are testing:

RasPiComm+Extensions

CAN bus, RS-485, 8 inputs and 8 outputs RasPiComm+ extension boards

  • 8 Input (with adjustable reference voltage, can be jumpered to 5V or 24V or fed from outside)
  • 8 Outputs (5V or 24V or fed from outside)
  • GSM module
  • RS-485 (two RS-485 on one board)
  • CAN (two CAN bus ports on one board, you’ll need the ARM Cortex-M4 option to use both simultaneously)
  • 16 isolated I/O (using th iC Haus iC-JX)

The firmware of the Cortex M3/M4F (both can be populated) will provide a bridge from the extension boards to the Raspberry Pi and interface with the drivers. The ARM microcontroller can be programmed from the Raspberry Pi for power users. It will come with a fully functional firmware and does not need to be changed though. If you want do do realtime or high relieability stuff you can do this by programming the ARM microcontroller.

The CPLD is also programmable via the Raspberry Pi, so changing configurations for different extension modules is easy.

RasPiComm+ bottom side

RasPiComm+ bottom side

The big metal box on the bottom side is an isolated DC/DC converter. This will be optional and powers both the RasPiComm+ and the Raspberry Pi from a 24V power supply. The battery holder is for the real-time clock backup battery for which we will also add driver support, so that the Raspberry Pi can get the current date and time.

The driver is very elegant I think. You can dynamically load and unload driver modules and they create an interface (for example /dev/ttyRPC0) to the specified module in case the module is a serial module (this applies to the GSM, RS-485 and the CAN module). This is already working quite well, we successfully sent SMS messages from the Raspberry Pi.

For the I/O modules we are looking into a driver interface similar to the Raspberry Pi GPIOs, but this is still work in progress, if you have suggestions what the best way is to implement I/Os leave a message 🙂

I will post separate articles about the RPCP extension boards to explain them in detail.

And if you have any other ideas how to make the RasPiComm+ even better let me know!

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