[MinnowBoard] Problem booting with activity on I2S_FRM

Darren Hart dvhart at linux.intel.com
Fri Mar 27 23:45:29 UTC 2015



On 3/27/15 2:24 PM, Lucas De Marchi wrote:
> Hey,
> 
> I'm using the pin GPIO_I2S_FRM for gpio in my application. However
> when I boot the board, if there's any activity on this pin already,
> the board doens't boot. I get nothing on serial, not even the messages
> from the bios. As far as I tested this is the only pin that exhibits
> this behavior.
> 
> Firmware version is 0.78.  Is there anything that can be done to boot
> the board even with activity on this pin?

Thank you for reporting this Lucas. I've looked into the design
documents and that pin is also a strapping line which happens to select
the BIOS boot:

0=LPC
1=SPI

While there is a buffer/voltage-shifter between the LSE connector and
the SoC, it is possible that a low signal to the LSE connector is
causing the SoC side of the signal to be pulled low, overpowering the
10k strap pull-up, effectively telling the SoC to boot via LPC instead
of SPI, causing the issue you describe.

Can you describe exactly what activity you have applied to this pin at boot?

-- 
Darren Hart
Intel Open Source Technology Center


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