Vida CEM swapping

Quattrodag · Post by **Quattrodag** » 16 Apr 2021, 03:30

I collected the board but I can not read the pin code, tell me what is wrong, I collected it according to this scheme

T5Luke · Post by **T5Luke** » 16 Apr 2021, 03:40

Is pin 10 of teensy connected to CAN?

Post by **RickHaleParker** » 16 Apr 2021, 04:13

Quattrodag wrote: 16 Apr 2021, 03:30 I collected the board but I can not read the pin code, tell me what is wrong, I collected it according to this scheme

That schematic is missing a jumper from Pin #4 to Pin #30 per the schematic, Pins 2 & 23 per the markings on the Teensy board.
The string of all zeros in the output indicates the jumper is what you are missing. It is the Latency detector, the beating heart of the whole cracking system.

Impedance mismatch from CAN transceivers to OBD connector. Get some twisted pair CAN Bus out of a junk car. The size and twist rate is part of the circuit balance.

I do not see the any 120Ω terminating resistors on the CAN transceivers. Unless they are installed backwards.

What is that in the corner of the picture where I placed an arrow?

: QuattrodagPCB.jpeg (163.92 KiB) Viewed 954 times

T5Luke · Post by **T5Luke** » 16 Apr 2021, 04:37

When you try it on bench you should need 2 120 Ohm CAN resistors per line.
When you try in car you should need no resistor.

This resistors are to terminate. They kill the signal on the line. If you have less resistance the message stays longer on the line. If you have much resistance the message gets very fast "converted to heat" and is not long measureable on line. The specification writes about 2 ends with 120 Ohm, so when you measure can by multimeter you should measure 60 Ohm in total. Also verified with VTL useing just one 120 Ohm resistor has some effect on timing. If you have wrong resistor setup, this can cause background noise you won't need.

Post by **vtl** » 16 Apr 2021, 05:19

RickHaleParker wrote: 16 Apr 2021, 04:13 That schematic is missing a jumper from Pin #4 to Pin #30 per the schematic

This was fixed long ago. People get the source code once and never update it

bosse · Post by **bosse** » 16 Apr 2021, 09:54

Ground is missing.

Post by **RickHaleParker** » 16 Apr 2021, 09:57

vtl wrote: 16 Apr 2021, 05:19 This was fixed long ago. People get the source code once and never update it

I'm still trying to figure out how to use Github. It is slow going because the documentation is a joke.

Post by **vtl** » 16 Apr 2021, 11:04

RickHaleParker wrote: 16 Apr 2021, 09:57 I'm still trying to figure out how to use Github. It is slow going because the documentation is a joke.

https://git-scm.com/book/en/v2

Post by **RickHaleParker** » 16 Apr 2021, 11:13

vtl wrote: 16 Apr 2021, 11:04 https://git-scm.com/book/en/v2

I'll add the 522 pages on Git to the 262 pages on Arduino C.

Post by **vtl** » 16 Apr 2021, 11:24

RickHaleParker wrote: 16 Apr 2021, 11:13
vtl wrote: 16 Apr 2021, 11:04 https://git-scm.com/book/en/v2
I'll add the 522 pages on Git to the 262 pages on Arduino C.

Ha-ha

Git basic workflow is very simple. clone, checkout, pull, log, diff and that's about it for the occasional observer.