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Topic: Haltech elite canbus reader (Read 418 times) previous topic - next topic

Klaus_K

#15
Sep 22, 2020, 02:37 am Last Edit: Sep 22, 2020, 10:51 pm by Klaus_K
What about this module? Feel free to link any usa Amazon links.
That is just a transceiver. It converts the digital pins of the CAN module into differential signals on the bus.

Look for something like this

Amazon.com Comidox-MCP2515-Receiver-Controller-Development

The module should have

- a MCP2515 CAN controller (needs a 8MHz crystal next to it to generate all standard CAN bitrates)
- a CAN transceiver (see above) there are different ones
- SPI connection pins
- CAN LOW and HIGH connection
- 120 Ohm termination resistor with jumper is a nice to have

That's all on the board above and it say $8.99 for three of them.

Edit: For 1MBit/s a 16MHz crystal is needed. 8MHz allows standard bits rates up to 500kBits/s

supertoast4939

I can't remember where or what it was I was reading but it said something about 8mhz crystals not working well with car canbus. Would a 16mhz crystal be better? I might be miss remembering....

mikb55

I can't remember where or what it was I was reading but it said something about 8mhz crystals not working well with car canbus. Would a 16mhz crystal be better? I might be miss remembering....
Usually not a problem as most libraries allow you to set the clock to 8 or 16MHz.

Klaus_K

I can't remember where or what it was I was reading but it said something about 8mhz crystals not working well with car canbus. Would a 16mhz crystal be better? I might be miss remembering....
You are right. I mixed up the internal clock from the external one. There is a fixed 2x clock divide.

The MCP2510/2515 can create most of the standard CAN bitrates (5,10,20,50,100,125,250,500kbit/s) from a 8MHz crystal, but not 1MBit/s. For 1MBits/s you need at least a 16MHz crystal. There are non-standard bit rates that cannot be created from 8/16MHz. It comes down to the dividers inside the CAN controller.

supertoast4939

I read on another post that the haltech elite ecu does 1MBit canbit rate. In other interesting news I did get some output from my 2009 bmw 328i . Though it was only the same code and only the RX light on the can board was flashing. I'll find a new 16mhz canbus board without a extra mirco controller.

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