[MinnowBoard] Need to disable both UART on LSE?

[Berth-Olof Bergman]

If you don’t use the BIOS and setup the pad configuration registers yourself, you should be able to use both of the pins without disable both UARTs.


> 29 apr 2015 kl. 00:27 skrev Lucas De Marchi <lucas.de.marchi at gmail.com>:
> 
> Hi,
> 
> Do I need to disable both UART1 and UART2 in UEFI in order to be able
> to use pin 12 in the LSE (GPIO_UART1_RTS)?  If I disable only UART1 I
> still can't use it:
> 
> [root at localhost ~]# echo 484 > /sys/class/gpio/export
> [   11.943332] byt_gpio INT33FC:00: pin 74 cannot be used as GPIO.
> -bash: echo: write error: Invalid argument
> 
> Pin 10 works fine though.
> 
> The only way I'm able to use pin 12 as GPIO is if I disable both UART1
> *and* UART2.
> 
> Also I'm surprised I actually have to disable any of them since pin 12
> is RTS. Wouldn't it be sufficient to disable flow control?
> 
> Here I have kernel 3.19.5 and firmware 0.77.  I also tried updating to
> 0.79 with no difference in behavior.
> 
> 
> thanks
> 
> -- 
> Lucas De Marchi
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