Custom AT91SAM9N12 SBC

Discussion around AT91RM9200 and SAM9 Series Products.

Moderator: nferre

Posts: 1
Joined: Wed Aug 03, 2016 8:44 pm

Custom AT91SAM9N12 SBC

Wed Aug 03, 2016 11:16 pm


I am currently working on a project to bring up a custom SBC based on the AT91SAM9N12 ATMEL MPU. I have based my project on Hak8or and Henrik's designs for the same processor. I have designed the board and gotten it manufactured and then populated. Once it was put together I fixed a few power issues, but now I am having problems getting the processor to boot up.

BMS is currently pulled high so that the processor will go into Debug mode on startup, however I am never getting to startup. The processor is keeping SHDN pin high and NRST pulled low, meaning that the Reset Controller is working, however it never goes into the boot up stage.

I am not sure where to go from here, the NRST net is working as intended, however the processor will not go out of reset mode. Is there something I am missing? Maybe something I forgot to account for? If someone can help me get another set of eyes on the issue I would greatly appreciate it.

My hope is for the processor to boot up and output something on the Debug UART, or be recognized by Windows or Linux as a USB CDC device.

Unfortunately I did not add JTAG to the board.

The Schematics along with the reference projects can be found at my github:

Hak8or's project: ... t91sam9n12
Henrik's project:

If you would like for me to send you a board to help test then just let me know and we can figure something out. (they're pretty cheap).
Location: USA
Posts: 2016
Joined: Thu Apr 19, 2007 10:15 pm

Re: Custom AT91SAM9N12 SBC

Thu Aug 04, 2016 12:37 am

How well have you addressed "the three most typical bring-up pitfalls: power, clocks, and reset"?
See discussions/viewtopic.php/p,38693.html#p38693 for a link to a guide, esp chapter 6.


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