Thanks, Graham. You are correct. I have already used these pins before, but 
for output purposes, so, I had no issues with that. But, since using as 
inputs, the switches are driving the pins and changing the SYSBOOT (aka 
LCDDATA) bus, which I had no idea that existed for my unfortunate surprise. 
I guess I'll have to redesign my boards including a tristate buffer.

Paulo Sherring.

Em quarta-feira, 15 de novembro de 2017 16:59:03 UTC-3, Graham escreveu:
>
> You have apparently used two pins that conflict with the boot 
> configuration pins on the BBB, or the eMMC.
>
> Read the "BeagleBone Black System Reference Manual" (Version C.1), pages 
> 62, 63, 68, 82, 106, 107.
>
> --- Graham
>
> ==
>
> On Wednesday, November 15, 2017 at 1:48:34 PM UTC-6, Paulo Sherring wrote:
>>
>> Hi, all. I have a beaglebone green connected to a custom cape. I am 
>> running the latest machinekit image.
>> I have it all configured and runs mostly OK. I am having an issue with 
>> end switch circuitry.
>> The switched are connected to P8_41 and P8_42 and are connected through 
>> the circuit in the attachment (BJT with open collector, connected through 
>> load resistor and internal pullup). If the end switch is opened, the board 
>> wont boot at all. If the end switch is closed, the board boots without any 
>> further issue. 
>> My question is: is there any blocking mechanism that prevents CPU from 
>> booting if, for example, any input is driver high?
>>
>> Thanks in advance!
>> Paulo Sherring.
>>
>

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