All details of this project can be found on www.dutchtronix.com.

Additional Notes for the Adafruit Ultimate GPS:Remove the 1PPS connector header on the Dutchtronix oscilloscope clock PCBA and connect the Ultimate GPS 1PPS output to the 1PPS input on the 1PPS connector pad. Commands must be entered into the Ultimate GPS, before connection of RX input and TX output, respectively, to the Dutchtronix TXROUTE and RXROUTE serial interface connections and the Dutchtronix oscilloscope clock must be set up to communitate with the GPS and the "M" command needs to be sent to the Dutchtronix Oscilloscope Clock, before the physical connection is made. To preserve the settings for the Ultimate GPS, connect the backup battery connection (connect directly to the battery + pad on the PCB and GND pin) to the backup battery pads on the Ducthtronix clock PCBA. Connect the Ultimate GPS Vin pin to the +5V supply on the Dutchtronix clock PCBA. Set the Ultimate GPS to communicate at 4800 baud and to ouput $GPRMC data only, once every 5 seconds. Set the Dutchtronix oscillioscope clock GPS setting and the baud to 4800 (should change to 4800 baud when the GPS setting is completed). Then connect the serial port of the ultimate GPS to the TXROUTE and RXROUTE pins on the Dutchtronix oscilloscope clock PCBA.

Ultimate GPS Command for 4800 baud: 

$PMTK251,4800*14<CR><LF>

Ultimate GPS Command for 9600 baud (default):

$PMTK251,9600*17<CR><LF>

Ultimte GPS Command for 19200 baud:

$PMTK251,19200*22<CR><LF>

Ultimate GPS Command to set the Ultimate GPS to output $GPRMC data only, once every 5 seconds: $PMTK314,0,5,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*2D<CR><LF>

Note:as shown in the figure above，traces to the RS232 3-pin header have been modified to accommodate the Adafruit Ultimate GPS connection to TXROUTE and RXROUTE on the Dutchtronix oscilloscope clock PCBA for TTL level serial port operation. The Adafruit Ultimate GPS board was mounted using 1/16 inch thick 3M 110 double sided foam tape stuck to the top of the PCF8563P RTC clock chip and top edge of the ATMEGA328P. To program the Ultimate GPS, an adapter was made to connect the USB 5V TTL level serial port to the 3-pin connector attached to the Ultimate GPS. The Realterm serial port software was used for communication to program the Ultimate GPS.