No Atmel Start USB examples work

Go To Last Post
3 posts / 0 new
Author
Message
#1
  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I've got a SAMS70N19 board. SAM-BA running from ROM works just fine, but I've tried to make multiple Atmel Start USB device projects, and none of them work.

 

One thing that seems odd to me is that I've provisioned the board with a 16 MHz crystal - which is supposed to work (indeed, SAM-BA seems happy), but I don't see anything in the config where you tell the UPLL what the frequency is. Does it just "know" whether it's 12 or 16 MHz?

 

Has anyone gotten an Atmel Start USB device example to work on any x70 ?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 0

I scrounged around and found ONE 12 MHz crystal. With that, the device gets much, much further.

 

From what I can tell, they really, REALLY want you to use a 12 MHz crystal - the CPU clock winds up being 300 MHz instead of 288, among other things.

 

But it kinda remains a question - A 16 MHz crystal is *supposed* to work, isn't it? How?

  • 1
  • 2
  • 3
  • 4
  • 5
Total votes: 1

Microchip support got back to me. There's a UTMI_CKTRIM register that has a bit you have to flip for 16 MHz. There's seemingly no knob in Start to do this - you have to do it yourself.