just to verify some things before I order design of my capes: according to http://elinux.org/Beagleboard:BeagleBoneBlack#Expansion_Header_Usage it is not allowed to have an input signal on any of the GPIO-pins during power-up or during boot. Resulting from that I think about using SYS_RESETn as signal to enable my capes. So my question:
which current can be pulled out ot SYS_RESETn / how much GPIO-inputs can I drive with this signal?
when SYS_RESETn is HIGH the GPIOs may not be programmed as input (because firmware is not fully started at this point) but the Cape-hardware possibly sets an input signal to them (because SYS_RESETn already enabled it). Is this a problem? Can I use SYS_RESETn to enable input signals too or should I use an additional GPIO as output which enables such signals much later than SYS_RESETn would do that?
Thanks for clarification!