[MinnowBoard] Problem booting with activity on I2S_FRM
david.anders at intel.com
Sat Mar 28 00:04:22 UTC 2015
Darren is correct that this is a boot strap pin, and I'd recommend using a different one if you are using it directly as a GPIO on startup, or else take care that it is not pulled low on reset...
From: elinux-MinnowBoard [mailto:elinux-minnowboard-bounces at lists.elinux.org] On Behalf Of Darren Hart
Sent: Friday, March 27, 2015 6:45 PM
To: MinnowBoard Development and Community Discussion
Subject: Re: [MinnowBoard] Problem booting with activity on I2S_FRM
On 3/27/15 2:24 PM, Lucas De Marchi wrote:
> 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:
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?
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