Teensy 4.0

Question

Teensy 4.0

brandonros opened this issue 5 years ago · comments

Is Teensy 4.0 supported?

Nathan Fain · Answer 1 · Sun Dec 15 2019 20:22:48 GMT+0800 (China Standard Time)

Yes, I think so. If Teensy 4.0 has support in Teensyduino then it will work without or with very little modification to JTAGenum. I see on the Teensy 4 release page that they say Teensyduino can be used to program Teensy 4.0 ("Teensy 4.0 can be programmed using the Arduino IDE with Teensyduino add-on."). I have not had a chance to test it yet.

Brandon Ros · Answer 2 · Mon Dec 16 2019 10:49:51 GMT+0800 (China Standard Time)

Can you recommend what pins I would need to connect? I have a 2x5 (10-pin) JTAG header I am trying to reverse engineer with a Teensy 4 and could use a bit of direction if you don't mind.

Nathan Fain · Answer 3 · Sun Dec 22 2019 15:52:51 GMT+0800 (China Standard Time)

This board looks very welcoming to RE. Have you checked if you can find a footprint for the MCU. Because there are so many traces you may be able to map the JTAG pins, or at least map one to confirm it is connected. (which is likely). Next we would want to check if the MCU has any security features to disable JTAG through fuses, which we may or may not find in the general datasheet.

Brandon Ros · Answer 4 · Sun Dec 22 2019 22:39:25 GMT+0800 (China Standard Time)

https://www.continental.com/en/press/press-releases/2017-03-28-control-unit-e-class-64576

Next we would want to check if the MCU has any security features to disable JTAG through fuses, which we may or may not find in the general datasheet.

I believe JTAG is disabled since this is a "production" device but I thought at least IDCODE would work.

I'm not sure if I need some kind of fuse/resistor to enable it. Any thoughts/ideas?

https://www.infineon.com/dgdl/Infineon-TC27xDC-DS-v01_00-EN.pdf?fileId=5546d462694c98b4016953972c57046a

I am under the impression that I can't trace because a) the board is multiple layers and b) the chip is in a special FBGA packaging that hides the pins?

I'd love to pair with you on this. Any advice? I think one mistake I am making is I am putting GND in the pin array, but taking it out yields no difference.

Brandon Ros · Answer 5 · Sun Dec 22 2019 22:48:44 GMT+0800 (China Standard Time)

Brandon Ros commented 5 years ago

Brandon Ros · Answer 6 · Sun Dec 22 2019 22:59:02 GMT+0800 (China Standard Time)

Brandon Ros commented 5 years ago

Brandon Ros · Answer 7 · Mon Dec 23 2019 02:00:04 GMT+0800 (China Standard Time)

I am told there is no external MCU. All of the other chips on the board are auxilliary chips for converting voltage levels from TTL to CAN-H/L etc.

Gerhard Klostermeier · Answer 8 · Wed Apr 29 2020 20:30:18 GMT+0800 (China Standard Time)

First time JTAGenum user here:
I'm using a Teensy 4.0 at a know JTAG port (dev board). The method IDCODE scan works, but not very reliable. I've noticed that I get better results when downclocking the Teensy to 150MHz instead of 600MHz. Is this normal? Is it more reliable on an Arduino?

OT:
The output is very verbose for cases where it needn't to be. With IDCODE scan TDI can not be identified. Why printing different pin layouts where only TDI changes?