I think this is kinda what it's always done with Ioniq5, but this is with the timing patch applied.. if I go from State=0 .. so no polling which means NOTHING received on the CAN bus, to State=1 (Vehicle on - lotsa polling including every second) where it starts polling, I get:

E (36101885) can: can1: intr=18642 rxpkt=11924 txpkt=6700 errflags=0x8000d9 rxerr=0 txerr=8 rxinval=0 rxovr=0 txovr=0 txdelay=0 txfail=1 wdgreset=0 errreset=1
E (36101885) can: can1: intr=18646 rxpkt=11924 txpkt=6700 errflags=0x8000d9 rxerr=0 txerr=40 rxinval=0 rxovr=0 txovr=0 txdelay=0 txfail=1 wdgreset=0 errreset=1
E (36101885) can: can1: intr=18648 rxpkt=11924 txpkt=6700 errflags=0x8000d9 rxerr=0 txerr=56 rxinval=0 rxovr=0 txovr=0 txdelay=0 txfail=1 wdgreset=0 errreset=1
E (36101885) can: can1: intr=18650 rxpkt=11924 txpkt=6700 errflags=0x8000d9 rxerr=0 txerr=72 rxinval=0 rxovr=0 txovr=0 txdelay=0 txfail=1 wdgreset=0 errreset=1
E (36101885) can: can1: intr=18652 rxpkt=11924 txpkt=6700 errflags=0x8000d9 rxerr=0 txerr=88 rxinval=0 rxovr=0 txovr=0 txdelay=0 txfail=1 wdgreset=0 errreset=1
E (36101885) can: can1: intr=18654 rxpkt=11924 txpkt=6700 errflags=0x8040d9 rxerr=0 txerr=104 rxinval=0 rxovr=0 txovr=0 txdelay=0 txfail=1 wdgreset=0 errreset=1
E (36101885) can: can1: intr=18655 rxpkt=11924 txpkt=6700 errflags=0x8040d9 rxerr=0 txerr=112 rxinval=0 rxovr=0 txovr=0 txdelay=0 txfail=1 wdgreset=0 errreset=1
E (36101885) can: can1: intr=18659 rxpkt=11924 txpkt=6700 errflags=0x204800 rxerr=0 txerr=128 rxinval=0 rxovr=0 txovr=0 txdelay=0 txfail=1 wdgreset=0 errreset=1

.... followed by

E (36145665) esp32can: can1 stuck bus-off error state (errflags=0x00040c00) detected - resetting bus

And then things seem to be good from there. I have bus 1 registered as active 500kbps

RegisterCanBus(1, CAN_MODE_ACTIVE, CAN_SPEED_500KBPS);

//.ichael

On Sat, 25 Jan 2025 at 09:58, Mark Webb-Johnson via OvmsDev <ovmsdev@lists.openvehicles.com> wrote:

Nice work. Thanks.

Mark

> On Jan 25, 2025, at 2:52 AM, Michael Balzer via OvmsDev <ovmsdev@lists.openvehicles.com> wrote:
>
> I was too quick on this conclusion:
>
>> Am 19.01.25 um 12:48 schrieb Michael Balzer via OvmsDev:
>> Regarding CAN timing, our ESP32CAN/SJA1000 configuration is mostly according to the SAE/CiA recommendations, with one exception: we generally enable multi (triple) sampling, regardless of the bus speed
>
> I trusted this CAN timing tool: https://www.esacademy.com/en/library/calculators/sja1000-timing-calculator.html
> …because it claims it applies the CiA recommendation. That turns out to either be not true or to be different from the SAE recommendation.
>
> I've had another look at the SAE J2284-3 spec.
>
> TL;DR: our sampling point is too late and our tolerance for timing variances of other devices on the bus is too low, at least for the usual 500 kbit/s bus speed.
>
> For 500 kbit/s, SAE J2284-3 defines SJW=3 and TSEG2=3 at tq=125ns, or SJW=3 and TSEG2=3…5 at tq=100ns, resulting in the sampling point being in the range 75-85%.
>
> Our driver currently uses tq=125ns with SJW=2 and TSEG2=2, sampling at 87.5%, so clearly outside the recommendation.
>
> The ESP-IDF driver configuration uses the tq=100ns setup, and places TSEG2 at 4:
> #define CAN_TIMING_CONFIG_500KBITS() {.brp = 8, .tseg_1 = 15, .tseg_2 = 4, .sjw = 3, .triple_sampling = false}
> → bus clock = .brp / 80 MHz → tq=100ns, with sampling at tq 16 of 20 = 80% -- this is exactly as recommended by SAE.
>
> I now test this configuration in my Mii, so far without issues.
>
> To test this timing, apply the attached patch, this also includes the SAE 500 kbit/s timing for can2/3.
>
> Regards,
> Michael
>
> --
> Michael Balzer * Am Rahmen 5 * D-58313 Herdecke
> Fon 02330 9104094 * Handy 0176 20698926
>
> <can1-sae.diff>
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