Custom Teensy 3.2 with empty processor works?

[thomas7]

Hello,

i want to try to build a custom teensy 3.2 board.

For that i will of course buy the Bootloader Chip from pjrc.

But does the Processor need anything? Can i just buy an empty processor and it will work "out of the box" to upload a program?

Thanks,
Thomas

 

[GremlinWrangler]

Empty processors work since the bootloader chip is fully capable of taking it over and staging it up to be a functional Teensy. Doing a google search of the forum for custom teensy would be a good idea since there are a lot of previous lessons learned by others around.

 

[WMXZ]

Only thing is, for an empty processor, that is, not running a usb capable program, you need to press the program button for the first upload to tell the bootloader chip to take over.

 

[thomas7]

Thanks a lot.
OK so i need this button, i thought i could get rid of it.

 

[GremlinWrangler]

If the plan is to only ever program these once you can get creative with the button and just have solder pads or similar. Or if really confident in your code make the bootloader a production line programing tool and put a matched programing header on your board and save the space and parts. This can leave you like this though

https://www.sparkfun.com/news/1575

Unless you are really confident of your PCB design and faultfinding skills would be better to move towards a solution like that in small steps.

 

[thomas7]

Thanks,

the plan is to upload every update (maybe 2 per month). But i never need to press the button on my teensy 3.2
But if this is just because the program has USB activated i can upload every custom board one time with a program like the original blink and everything will be ok.

My custom pcb is allready done and protoyp works, but it used a processor and bootloader chip from original teensy 3.2
thats why it worked directly and i was not sure about a new fresh processor.

But now i know that an empty processor will not work without this button, i will do something like a "wire bridge" for the first update and then all the uploaded programs will have usb activated and work without it.

Thanks a lot.