[ntp:questions] Trying to use Dimension 4 time keeper

unruh unruh at invalid.ca
Wed Sep 25 15:40:47 UTC 2013


On 2013-09-25, John Hasler <jhasler at newsguy.com> wrote:
> I wrote:
>> The Pi GPIO pins have pullups.  Just use an open-collector driver.
>
> unruh writes:
>> That of course assumes that you, not the designer of the gps card say,
>> have designed the output.
>
> I'm suggesting adding an open-collector driver rather than adding a
> network of resistors and diodes.  Fewer parts and better results.

Probably. I'm a bit worried if the base voltage is higher than the
collector. 



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