[Arm-netbook] help needed with a ttl logic circuit

Dominique Dumont domi.dumont at free.fr
Sun Aug 23 18:37:32 BST 2015

On Sunday 23 August 2015 15:52:27 Luke Kenneth Casson Leighton wrote:
> http://hands.com/~lkcl/ttl_logic_circuit2.png
> still don't feel completely happy (esp. with the schottky diode), i
> feel another transistor might be needed especially because VREFTTL
> (for the EOMA68_BOOT0 TTL level) could be *lower* than 3.3v.

There's no resistor to limit the current when ext_boot0 is up (from ext_boot0 
to gnd).

But the schottky diode will prevent any current to go there... I don't see how 
the first transistor can be switched on...

 https://github.com/dod38fr/   -o- http://search.cpan.org/~ddumont/
http://ddumont.wordpress.com/  -o-   irc: dod at irc.debian.org

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