What details would you like to know? Serial port 3 and 4 are provided via the GPIO pins connected to an NCT5104D I/O controller which is 5V tolerant. http://datasheet.octopart.com/NCT5104D-Nuvoton-datasheet-38893851.pdf I believe that's why it was suggested to avoid the 3V-5V conversion.
-----Original Message----- From: time-nuts [mailto:[email protected]] On Behalf Of Chris Albertson Sent: Sunday, August 14, 2016 12:01 PM To: Discussion of precise time and frequency measurement <[email protected]> Subject: Re: [time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd It looks like you would have to level-convert the 3 volt PPS to connect to one of the GPIO pins. It is easy to make a level converter with a FET or you can buy one for $3 from Adafruit or spark fun. As for the serial data, that will be easy as there seems to be a 3 volt serial port. The direct connection that was suggested might work or might not it depends on some details we don't know. Seems like a good low power embedded PC. Very much over kill for just running NTP but I assume this will do other things too. On Sat, Aug 13, 2016 at 7:32 PM, STR . <[email protected]> wrote: > Hi, > > > > I recently bought 2 ublox PCI-5S mini-PCI GPS modules and have ordered > a PCengines APU2C4 board I hope to install it in. > > Others have found it can provide PPS output http://emerythacks.blogspot. > in/2013/01/u-blox-pci-5s-cheap-gps-module-for-your.html > > > > This is the x-64 AMD SoC by PCengines - > http://www.pcengines.ch/apu2c4.htm > > Schematics - http://www.pcengines.ch/schema/apu2c.pdf > > User manual (Page 8 has a nice overview of the board) - > http://www.pcengines.ch/pdf/apu2.pdf > > > > I would like to install and power the GPS from the mini-PCI slot and > output PPS directly on to one of the serial ports on the SoC board for ntpd. > > Since mini-PCI uses 3.3V and serial uses 5V I guess, I'm not sure how > to achieve this and am concerned I might fry the board. > > > > Do I need a MAX 232 voltage converter? > > Can this be done using the mini-PCI slot for power? > > > > I have posted my issue on the PCengines forum and got 1 response so > far that suggested I connect to COM3 on the GPIO header - > > http://www.pcengines.info/forums/?page=post&id=B4D54F22- > 8224-4A67-9F9E-85F988A1F888&fid=DF5ACB70-99C4-4C61-AFA6-4C0E0DB05B2A > > I'm not sure where exactly, these are the GPIO pins on the board > http://imgur.com/a/bAZLb > > > > When someone says "LPC serial IRQ and system interrupt latency will > add up to noticeable jitter" does that mean the jitter would be > equally bad from any serial port on the board or just from the 3rd serial off > the GPIO pins? > > Here, someone else claims the PPS should have less jitter in a similar > setup - http://pcengines.info/forums/?page=post&id=CD275C4D-8050- > 408A-BD16-6F50468C74C2 > > > > I'm hoping someone here could help me out with this as I'm well in > over my head by now. > > > > > > > > Cheers, > > S > > _______________________________________________ > time-nuts mailing list -- [email protected] To unsubscribe, go to > https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow > the instructions there. > -- Chris Albertson Redondo Beach, California _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
