Thanks for the quick feedback, guys. I'll probably breadboard up a transistor for now, and a little converter like that can permanently go inline in my connecting cable even though I only need a single channel. It would be cool if someone made a breakout board for the pi that had an optional level converter on every (or even several) gpio output, that would be really useful for prototyping.
On Wed, Dec 30, 2015 at 5:29 PM, David Forbes <[email protected]> wrote: > Andy, > > You can use an NPN transistor (2N3904 or 2N222A or whatever) and a couple > resistors to boost the Pi signal to 5V. Pi output through a 10K resistor to > Base, Emitter to Gnd, counter fed from Collector, Collector also tied to 5V > through a 1K resistor. Should work up to about 1 MHz. > > > On 12/30/15 2:54 PM, Andy Tefft wrote: > >> >> Initial quick tests are good with one exception - I had just connected an >> AVR output to one of the pins on the reset button on the counter and the >> AVR was able to toggle that output and reset the counter (pretty sure I >> was >> powering the AVR with 5V). This same trick does not work with the pi, >> presumably due to its puny little 3.3v-level outputs. Anyone have a >> standard, simple go-to for interfacing between old TTL circuitry and a pi >> or something like it? >> >> > > -- > David Forbes, Tucson AZ > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send an email to [email protected]. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/56845AE1.5070000%40dakotacom.net > . > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/CAM1F4kQzz%3DgMV0qcO26Je3DwkMbbGjxtC%2BD7Kwfpr04eX7tPsA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
