OVMS# can can1 start active 1000000

Can bus can1 started in mode active at speed 1000000bps

OVMS# can can2 start active 1000000

Can bus can2 started in mode active at speed 1000000bps

OVMS# test cantx can1 25000

Testing 25000 frames on can1

Transmitted 25000 frames in 6.466209s = 258us/frame

OVMS# can can1 status

CAN: can1

Mode: Active

Speed: 1000000

Interrupts: 24771

Rx pkt: 0

Rx err: 0

Rx ovrflw: 0

Tx pkt: 24880

Tx delays: 24703

Tx err: 0

Tx ovrflw: 109

Err flags: 0

OVMS# can can2 status

CAN: can2

Mode: Active

Speed: 1000000

Interrupts: 19084

Rx pkt: 24770

Rx err: 0

Rx ovrflw: 1

Tx pkt: 0

Tx delays: 0

Tx err: 0

Tx ovrflw: 0

Err flags: 0x2040

Note the err flags 0x2040 on CAN2, but the bus remains up and working fine.

Repeating the test gives us:

OVMS# test cantx can1 25000

Testing 25000 frames on can1

Transmitted 25000 frames in 6.479670s = 259us/frame

OVMS# can can1 status

CAN: can1

Mode: Active

Speed: 1000000

Interrupts: 49546

Rx pkt: 0

Rx err: 0

Rx ovrflw: 0

Tx pkt: 49771

Tx delays: 49417

Tx err: 0

Tx ovrflw: 207

Err flags: 0

OVMS# can can2 status

CAN: can2

Mode: Active

Speed: 1000000

Interrupts: 38288

Rx pkt: 49545

Rx err: 0

Rx ovrflw: 3

Tx pkt: 0

Tx delays: 0

Tx err: 0

Tx ovrflw: 0

Err flags: 0x2040

Looking at the mcp2515 code, it seems that Err flags are only stored "if (intstat & 0b10100000)”. That is "ERRF 0x80 = message tx/rx error” or "ERRIF 0x20 = overflow / error state change”. It is also set to "(intstat & 0b10100000) << 8 | errflag”, so doesn’t show all the error statuses. It is hard to rely on that for other errors/status on lock-up. Given that error_flags is a uint32_t, I think we can store more in it to allow for better diagnosis.

I changed the mcp2515 driver to always set error_flags, on each interrupt handled (except spurious interrupts with no flags found), as follows:

SSSSSSSSFFFFFFFF***EB01TLLLLLLLL

SSSSSSSS = intstat
FFFFFFFF = errflag
B = RXB0 or RXB1 overflow flags cleared
0 = RXB0 overflowed
1 = RXB1 overflowed
T = TX buffer has become available
E = Error/WakeUp flags were cleared
LLLLLLLL = intflag

I did find a problem on line 300: if (intstat & 0b10100000). It think that should be 0b11100000 (to also pickup the RXB0 overflow), and removed the m_status.rxbuf_overflow++ from RXB0 overflow (as it is not really an overflow - as RXB1 got the data).

With those changes made, I get:

OVMS# test cantx can1 25000
Testing 25000 frames on can1
Transmitted 25000 frames in 6.389849s = 255us/frame

OVMS# can can1 status
CAN: can1
Mode: Active
Speed: 1000000
Interrupts: 24777
Rx pkt: 0
Rx err: 0
Rx ovrflw: 0
Tx pkt: 24884
Tx delays: 24739
Tx err: 0
Tx ovrflw: 116
Err flags: 0x00000000

OVMS# can can2 status
CAN: can2
Mode: Active
Speed: 1000000
Interrupts: 18935
Rx pkt: 24777
Rx err: 0
Rx ovrflw: 0
Tx pkt: 0
Tx delays: 0
Tx err: 0
Tx ovrflw: 0
Err flags: 0x01000001

I don’t think I’ve fixed anything (apart from that minor issue with RXB0 overflow diagnostics), but hopefully the new error_flags display should help finding out what is causing this lockup. Hopefully I haven’t broken anything.

Regards, Mark.

On 7 Jul 2018, at 10:42 AM, Tom Parker <tom@carrott.org> wrote:

On 07/07/18 00:05, Mark Webb-Johnson wrote:
Err flags 0x2040. The 0x20 part is the error interrupt. The 0x40 part is "RX0OVR: Receive Buffer 0 Overflow Flag bit”.

Where the number on ‘can can2 status’ moving at all? Or completely stuck?

None of the can can2 status numbers change when the can bus is broken. After power cycling it they move.

Seems different than the fault Greg and I are seeing. This one likely to be interrupt flag, or buffer overflow, not being cleared correctly. I’m guessing the overflow because that just doesn’t seem correct in mcp2515::RxCallback(). I’ll focus on that and have a look.

I just checked the car again and it stopped with Rx ovrflw number only 1281, half what it got to last time.

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