[Ovmsdev] OVMS Poller module/singleton

[Chris Box]

I'm happy to try some new code on my Leaf. Which code should I use? The 
current master, or a different branch? It wasn't clear to me from the 
thread below.

Chris

On 2025-01-19 19:47, Derek Caudwell via OvmsDev wrote:

> I can't recall testing a later version but I think Chris can confirm he 
> was on a later version when his Leaf had a similar problem.
> 
> The Leaf is now my wife's daily drive so I won't be able to take a look 
> at making the suggested changes for a couple of weeks at least.
> 
> On Mon, 20 Jan 2025, 8:31 am Michael Balzer via OvmsDev, 
> <ovmsdev at lists.openvehicles.com> wrote: Derek,
> 
> Am 03.05.24 um 12:53 schrieb Derek Caudwell via OvmsDev: When running 
> firmware  3.3.004-74-gbd4e7196 on my Nissan Leaf I suspect (but can't 
> be 100% sure as it's only been 24h without fault) the new poller caused 
> the car to throw the attached faults from overloading the can bus 
> whilst driving. The fault was sufficient to send the car into limp mode 
> and could not be driven until cleared with LeafSpy.
> Build 3.3.004-74 (released 2024-04-30) did not yet include the poller 
> tracing control, i.e. it did lots of logging for frames, significantly 
> affecting overall performance.
> 
> Poller tracing control was introduced in 
> https://github.com/openvehicles/Open-Vehicle-Monitoring-System-3/commit/7e4046042a99339d0212aac8f874cc8f780e634e 
> on May 12.
> 
> That commit was first included in build 3.3.004-103-g11fddbf6 released 
> 2024-05-25. Do you remember testing that build or a later one?
> 
> But as I still don't understand how a software queue overflow could 
> cause a bus crash, I've also checked the 500 kbit timing for the 
> MCP2515 and found that may have the same issue as the 125 kbit timing:
> 
> Our timing is:
> case CAN_SPEED_500KBPS:
> cnf1=0x00; cnf2=0xf0; cnf3=0x86;
> = PROP=1, PS1=7, PS2=7, SJW=1, Sample 3x @56.3%
> 
> Remember, the SAE/CiA recommendation is SJW=2, Sample 1x @87.5%. That 
> would translate to:
> PROP=5, PS1=8, PS2=2, SJW=2, Sample 1x @87.5% =
> cnf1=0x40; cnf2=0xbc; cnf3=0x81;
> 
> I also checked the Arduino MCP_CAN lib, and that uses:
> cnf1=0x40; cnf2=0xe5; cnf3=0x83;
> = PROP=6, PS1=5, PS2=4, SJW=2, Sample 3x @75%
> 
> So our timing for 500 kbit/s on the MCP buses also isn't as 
> recommended.
> 
> Derek, could you test the SAE/CiA recommendation and the MCP_CAN config 
> as shown? Or anyone else with a live can2/can3 bus at 500 kbit?
> 
> If these work, the question is which is the more general setup we 
> should adopt. Apparently the MCP_CAN lib also does not follow the CiA 
> recommendation, I wonder if the MCP_CAN config is a compromise for 
> compatibility.
> 
> Regards,
> Michael
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