--Message-Boundary-28437 Content-type: text/plain; charset=US-ASCII Content-transfer-encoding: 7BIT Content-description: Mail message body On 26 Feb 2004 at 1:43, Edward Cooper wrote: > Hi > > I'm trying to connect a 3.3v GPS device to a 5v PIC, now I need to > adapt the signals. I've looked back in the archives, and Brent Brown > suggested the bellow, but I have a few questions. > > Should I add a 3.3v Zener too the RxD line to make sure it can't go > above 3.3v ever? > > Also is there not a simpler way of configuring the TxD line? Are > there chips for handling this sort of conversion? Hi Ed, That was just a circuit I had lying around, which is admittedly more complicated than what is necessary on hte Tx side and too simple on hte Rx side. Check out the attached circuit for something simpler/better. It shows interfacing of logic levels between a 3.3V device and a 5V device, in both directions. Note that the diode drop determines the logic 0 level, so schottky diodes would be best. Best regards, Brent. -- Brent Brown, Electronic Design Solutions 16 English Street, Hamilton, New Zealand Ph/fax: +64 7 849 0069 Mobile/txt: 025 334 069 eMail: brent.brown@clear.net.nz -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! 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