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ddworken / the-bus-pirate

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Protocol: CAN #11

Open GoogleCodeExporter opened 9 years ago

GoogleCodeExporter commented 9 years ago 
Controller area network protocol.

What type of physical layer transceiver is needed?

Original issue reported on code.google.com by ianles...@gmail.com on 31 Mar 2009 at 2:34

GoogleCodeExporter commented 9 years ago 
A transceiver is needed.  From my research, microchip can provide everything 
needed.
 Looking at the datasheet for the pic being used, it does not support CAN.  My
suggestion would be to change to a PIC that does have CAN support or use an 
external
SPI controlled CAN module.  The microchip can module that would be the best 
would be
MCP2515.  If you want to make coding simpler, you might be able to change to a
PIC24HJ128GP502 controller.  It should be pin for pin compatible and have 
almost the
same features.

The physical layer also needs a transceiver.  Microchip again provides a 
transceiver
option.  Their transceiver is the MCP2551.

These are just my thoughts.  I would be rather interested if CAN were to be an 
option.

Original comment by Dr.Bob.B...@gmail.com on 10 Apr 2009 at 2:08

GoogleCodeExporter commented 9 years ago 
CAN, LIN, MIDI, etc require a breakout transceiver (and controller in the case 
of
CAN). We're got a few MCP2515s already on breakout boards. We still need to get 
a few
transceivers. The MCP2551 is good for both 12- and 24volt systems.

MCP2515: http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en010406
MCP2551: http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en010405

Original comment by ianles...@gmail.com on 10 Apr 2009 at 6:33

GoogleCodeExporter commented 9 years ago 
CAN doesn't necessarily require a dedicated controller though the software will 
be
very timing dependent and basically be a timer based bitbang mode.  It will 
need a
transceiver (costs about $1 on digikey in 1's) to translate from the 
differential
mode to SE signals the PIC can use.

Original comment by ads...@gmail.com on 7 Apr 2010 at 4:46