Just an idea, if you really don't have space for an extra resistor, the port B has internal pull-ups that can be enabled and might do the trick for you. You won't be able to use the I2C peripheral of the PIC in that situation as it is on port C and cannot be re-located on the 18F2520, but with a bit of bit banging, this is not a problem.
Michel On Apr 16, 3:37 am, Quixotic Nixotic <[email protected]> wrote: > People seem to find my Clock-It website and there's been a lot of interest > in my one and two tube clocks. I've got a reasonable set of fades and > display modes and I have also got a routine so the cathodes for each tube > can be swapped around by the user > > People keep asking me if I can supply a kit so I thought it was about time > I put something together for other people. So I am working on a small set > of modular boards, very much with the home constructor in mind, who tend to > not like soldering surface mount parts, so I am trying to avoid their use > completely, while designing a compact layout. The DS2321 will be the only > surface mount part, which I am going to have space for on the board, but > with the option to piggy-back a separate pre-soldered plug-in part which I > can supply if people don't feel up to soldering it themselves. > > The 18F2520 PIC ports I am using for the I2C bus say they are TTL, so > presumably they are not open collector, thus my question whether I need any > additional pullups. > > > > > > > > On Sunday, 15 April 2012 17:50:43 UTC+1, Quixotic Nixotic wrote: > > > I am driving a DS3231 I2C clock from a PIC's pins. If the logic state of > > the pins is always high or low, do I really need pullups on the bus? The > > only reason I ask is that space is at a premium. -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
