Hello. I connected the mcp2515 with the arduino uno in my car, to the obd socket and it worked fine. The next day I went to connect it again to the car and when connecting to the OBD socket, even with the MCP2515 turned off, the car shows an error in the ABS module and the CAN network error. I noticed that this occurs when I put the jumper to 8mhz. When it is at 16mhz it does not present any failures. I know this isn't about redecan, but does anyone have any idea what it could be? It only gives an error at 8mhz. If you can give me some light I would appreciate it
You are causing contention on the bus. Without seeing your setup I can only take a SWAG and say your module is putting garbage on the buss causing the system to error out. Also when you change the crystal did you change the MCP2515 setup to accommodate the change?
Yes, I changed it in the setup to 8 mhz. I bought another mcp 2515 module and it also gave an error on the can bus network. Is there a possibility that there was a defect in the 8 mhz can bus network? I don't really understand... I can copy the script I used too... Is there a way to clean this garbage on the can bus network?
If you are getting a mix of bad data and good data, process (display, use) only the good data.
Can you tell me how I can clean this rubbish?
When I connect the MCP 2515 to the car's OBD port and turn on the car key, the car already shows an error on the dashboard. No time to send or receive data
This is beyond my canbus knowledge. Sorry. Borrow a OBDII from a garage?
I have an obdll when I connect a diagbox scanner I can clear the faults in the modules with this scanner. but when connecting the mcp2515 again the errors return... if I connect at 16mhz it doesn't generate any error and if I connect at 8 mhz it generates an error... that's what I don't understand...
I am not sure about canbus termination, but two-wire data buses usually need termination resistors at the end of the two-wire to avoid signal reflection. Without the termination resistor, a signal hits the end of the two wire, inverts, and returns down the wire. A reflected signal can be seen as bad data or bad packets.
What can bus are you using, I do not know of any 16mhz can bus on an OBDII connector. Read this for starters then follow some tutorials on CAN bus and CAB bus controllers. After that do a few tutorials on CAN protocol. I am recommending these because they do not appear in your resource kit.
The MCP2515 does not work by itself it needs a controler of some type, what are you using. Since you have two MCP2515s get two arduino nano or UNO and download Corry Flowers library and connect as shown, the software does work.
Here's the link I found...
(fyi on the search: cory - one r, fowler - no s, canbus - not 2515)
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I will paste a YouTube link. I recorded it for you to see and better understand what happens.
the jumper on the mcp makes it work at 8mhz and without the jumper at 16mhz.
If you see in the video the panel has an error when it has the jumper generating faults in the CAN network, and without the jumper there are no faults. If you can see the video, I'm sorry because it is difficult to record and work at the same time.
The jumper adds a termination resistor. You don't need this when connecting to an existing CAN bus in your car.
Do you have a link to a web page that says it changes the frequency?
I don't know if I understood your question correctly... but it would be this link
I don't see anything that talks about a jumper changing the frequency.
Sorry, I misunderstood... the 8mhz is changed by the code... and the jumper is to activate the resistor... I made a mistake in my words. my car only works with the resistor... that's why it gives an error when I connect the jumper... regardless of whether it is at 8 or 16 mhz...
Do you have any idea what could be causing the can bus network to fail when I activate the resistor?
Every CAN bus in your car already has two termination resistors, one at either end. Adding another resistor lowers the impedance of the bus making it impossible for the transceivers to drive the data lines properly, and possibly causing them to overheat and shutdown.
One question... if I invert the wires of can h and can l on the obd2 connector, could this cause any problems on my can bus network?
example.. I'm connecting the mcp can h output to the obd2 can h and the car is failing. If I invert the fois, connect the mcp can h output to the obd2 can l, could this generate a short in the car's can network?
What confuses me is that even though the mcp board is turned off, it generates an error on the can bus network. If the board is turned off, it shouldn't interfere with the resistance, right?