Re: CAN message with DLC > 8 and PIC18

Am Mittwoch, 1. Juni 2016, 10:59:49 schrieb Alberto Alvarez:
> Hello list,
> 
> I am reading that reception buffers in Microchip PIC18 devices have a max
> length of 8bytes, so I can not receive any message with longer DLC.
> 
> I am investigating if using a overflow bit I can reach the second part of
> the longer message but without progress so far.
> Does anyone have experience with such devices? Do you know if it's even
> possible?
> 
> 
> Kind regards
> 
> 
> Alberto Álvarez


According to the classic CAN standard ISO11898 the maximum number of payload data bytes a CAN message has is eight. And that's the way all available implementations work. They buffer only 8 bytes. You can send a message with a DLC=15 but the transceiver only has a transmit buffer of eight bytes. And you can receive the DLC 15 but receive only the max number of eight bytes.

You can look for newer CAN controllers implementing CAN FD. CAN FD allows a payload up to 64 bytes. 

Regards
  Heinz
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