[time-nuts] How to get PPS from ublox mini-PCI GPS to APU2 SoC serial port for ntpd

STR . strykar at hotmail.com
Fri Nov 11 10:05:02 EST 2016

>The normal RS-232 level shifter chip includes an inverter.  (No good reason, just historical, but with a long history.)

>I can't understand the schematic on the part Gary suggested.  I'd use something like this:
>  https://www.sparkfun.com/products/11189


Thanks, this had me look closer at the outputs and not all RS232 chip breakout boards shift all signals, it seems to be 4-6 lines at most.
I've seen some MAX3232 (RS232 to TTL) converters, but the better ones only shift Rx, Tx, CTS, RTS, VCC and GND.

If I read what was suggested here earlier correctly, I need DCD for the PPS signal and Rx, Tx for NMEA.
I plan to use this with pfsense/gpsd which lets you choose between rising and falling edge for PPS signal processing.

I'll go ahead and order https://www.sparkfun.com/products/11189 as it appears to do all RS232 signals and can handle voltages > 5V.

Thank you all again!

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