SENT J2716 Protocol

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mtmotorsport
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Re: SENT J2716 Protocol

Post by mtmotorsport »

Fantastic results!

Is this direct to ECU SENT?
Matt
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AndreyB
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Re: SENT J2716 Protocol

Post by AndreyB »

mtmotorsport wrote:
Tue Nov 15, 2022 1:10 am
Fantastic results!

Is this direct to ECU SENT?
Yes, it's MRE 0.6.0 with C54 removed doing the SENT decoding. At the moment only microRusEFI has proper match of stm32 input-capture pin with a proper RC filter.

Tune https://rusefi.com/online/view.php?msq=1294&dialog=fancyHardwareDialog has magic Lua glue to have all this working
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Re: SENT J2716 Protocol

Post by AndreyB »

Shaky Ford tune just not to loose it https://rusefi.com/online/view.php?msq=1301
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Re: SENT J2716 Protocol

Post by AndreyB »

While Ford and GM units use same plug and same pinout and look extremely similar, Ford being newer is different enough - Ford has pause frame which GM did not use, also Ford has inverted decoding LOL just to make units incompatible.

Unresolved open issue where we are out of ideas for now:

GM real unit we have below 0.5% error rate - happy, very snappy control by the way https://rusefi.com/online/view.php?msq=1302

Ford trace fed into logic analyzer we have 0% error rate but real Ford unit we have close to 10% error rate :(

Which makes me want to try Ford with logic analyzer connected, be right back :)
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Re: SENT J2716 Protocol

Post by AndreyB »

Wow, yes, having logic analyzer hooked up helps with frame error ratio, so it's about extra capacitance or something like that?

Also @dron0gus has realized that encoding approach is different between units:

on GM nibble1+nibble2 is always 0xFFF, like maybe they have one sensor? cannot be that for redundancy but sure thing looks like that.

On Ford nibble2 value is much noiser than nibble1 (sig0) value which might mean that we do not know how to decode nibble2 (sig1).


2022-11-17_14_02_22_528: EngineState: Last valid fast msg Status 0x8 Sig0 0x238 Sig1 0xD89
2022-11-17_14_02_22_861: EngineState: Last valid fast msg Status 0x0 Sig0 0x238 Sig1 0xD2B
2022-11-17_14_02_22_863: EngineState: Last valid fast msg Status 0x8 Sig0 0x238 Sig1 0xDB2
2022-11-17_14_02_23_195: EngineState: Last valid fast msg Status 0x0 Sig0 0x238 Sig1 0xDA2
2022-11-17_14_02_23_197: EngineState: Last valid fast msg Status 0xC Sig0 0x238 Sig1 0xD4A
2022-11-17_14_02_23_529: EngineState: Last valid fast msg Status 0xC Sig0 0x237 Sig1 0xDD9
2022-11-17_14_02_23_647: EngineState: Last valid fast msg Status 0x8 Sig0 0x238 Sig1 0xDC2
2022-11-17_14_02_23_749: EngineState: Last valid fast msg Status 0x8 Sig0 0x237 Sig1 0xD9D
2022-11-17_14_02_24_081: EngineState: Last valid fast msg Status 0x0 Sig0 0x238 Sig1 0xDD0
2022-11-17_14_02_24_083: EngineState: Last valid fast msg Status 0x0 Sig0 0x238 Sig1 0xD67
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Re: SENT J2716 Protocol

Post by Dron_Gus »

On Ford:
nibble 0..2 - position.
nibble 3..4 - counter
nibble 5 - inverted nibble 0
Please note, that current code uses reverse order for sig1 = nibble 5, nibble 4, nibble 3

Code: Select all

{ 0x0f8, 0xf5f }, // counter 245, inverted 0xf
{ 0x0f8, 0xf6f }, // counter 246, inverted 0xf
{ 0x0f9, 0xf7f }, // counter 247, inverted 0xf
{ 0x0f8, 0xf8f }, // counter 248, inverted 0xf
{ 0x0f8, 0xf9f }, // counter 249, inverted 0xf
{ 0x0f7, 0xfdf }, // counter 253, inverted 0xf
{ 0x0f8, 0xfef }, // counter 254, inverted 0xf
{ 0x0f8, 0xfff }, // counter 255, inverted 0xf
{ 0x0f8, 0xf00 }, // counter 0, inverted 0xf
{ 0x0f7, 0xf30 }, // counter 3, inverted 0xf
{ 0x0f8, 0xf40 }, // counter 4, inverted 0xf
{ 0x0f8, 0xf50 }, // counter 5, inverted 0xf
{ 0x0f8, 0xf60 }, // counter 6, inverted 0xf
{ 0x0f8, 0xf70 }, // counter 7, inverted 0xf
{ 0x0f8, 0xf80 }, // counter 8, inverted 0xf
{ 0x0f8, 0xf90 }, // counter 9, inverted 0xf
{ 0x0f9, 0xfa0 }, // counter 10, inverted 0xf
{ 0x0f8, 0xfb0 }, // counter 11, inverted 0xf
{ 0x0f9, 0xfc0 }, // counter 12, inverted 0xf
{ 0x0f8, 0xfd0 }, // counter 13, inverted 0xf
{ 0x0f8, 0xfe0 }, // counter 14, inverted 0xf
{ 0x0f8, 0xff0 }, // counter 15, inverted 0xf
{ 0x0f8, 0xf01 }, // counter 16, inverted 0xf
{ 0x0f9, 0xf11 }, // counter 17, inverted 0xf
{ 0x0f8, 0xf21 }, // counter 18, inverted 0xf
{ 0x0f8, 0xf31 }, // counter 19, inverted 0xf
{ 0x0f8, 0xf51 }, // counter 21, inverted 0xf
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Re: SENT J2716 Protocol

Post by Dron_Gus »

Should we move sig0 and sig1 out of SEND core driver?
Looks like signal construction from nibbles is depends on device.
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