On 06/20/2017 04:41 PM, andy pugh wrote: >> What chip are you using? I did not notice any pull-ups, so I guess it >> must be an active translator chip you have. > I am pretty sure it was a GTL2000 > http://www.nxp.com/documents/data_sheet/GTL2000.pdf
It should work, but it is not "nice". There are several problems, especially wrt. the RPi outputs. How did the design perform in the real world? The application note (http://cache.nxp.com/documents/application_note/AN10145.pdf) states that the high-side must have pull-ups or they will never reach the high-side voltage. The second problem is that you load the RPi with the capacitance of the cable since the level shifter does not buffer for you. That will severely impact the rise time (and therefore propagation delay). The RPi GPIOs are not designed to take any significant load (max 3mA nominally). There will also be a significant timing skew in directions, depending the type of drivers used on the other side. -- Greetings Bertho (disclaimers are disclaimed) ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
