You can buy the chip already on the PCB with supporting circuitry for less then the price of the chip alone. No need to go with a bare chip. I think the reason is that the tiny SMT package chips sell in the millions and only a hob best would use the larger DIP through hole package. Look at eBay #221326355393 as an example. The 3>71 price includes shipping. The advantage is __Programming__. When you are working on something like this you tend to want to re-program the chips ten times an hour and it s VERY convenient to be able to leave it plugged into the USB port on your computer. Also for debugger a continuous stream of data on your computer screen, maybe captured to a file, gives yo insight to the internals.
That is the advantage of development with the Arduino vs. a bare chip, you don't have to pull the chip to re-program it. Yousimply change a line of code using a text editor and click the "load" icon and a few seconds later you are running again. It is a very fast development cycle. You don't save either cost or space by using a large DIP chip the SMD chip soldered to a PCB is about the same cost and size but also comes with the pull up resisters, voltage regulater, standard 6-pin FTDI interface and so on. On Thu, Feb 13, 2014 at 6:36 AM, paul swed <[email protected]> wrote: > Lars has done a very good job here and good to see the comments and > excitement. > Have to agree with HAL that holdover is far more than a second and I am in > a good location with the GPS antenna at 90'. I see my 3801 go into holdover > occasionally and its not seconds. > > Cheapest tinker 10 Mhz is a Xtal with a varicap diode in circuit to adjust > frequency. > Sub $ 5 I would guess. > > I was intrigued by the Arduino also and then went looking for information. > Just about drowned in whats out there and pricing for the chip is from 99 > cents to $5. > What bootloader X Y or Z. I like the pure chip 28 pin approach and do > appreciate that this won't be H maser accurate. > > Looked at the schematic and would appreciate a more complete picture. > Lars thats a bit more painful to do because everything has to be explicit > in the schematic when other may build what you have shared. > Though I have shared some ugly schematics on time-nuts. Guilty as charged. > Regards > Paul. > WB8TSL > > > On Thu, Feb 13, 2014 at 3:59 AM, Hal Murray <[email protected]> wrote: > >> >> [Context is cheap VCXO] >> >> > When used inside a GPSDO it only has to "hold over" for one second until >> the >> > next correction. >> >> Only if you have a good antenna and/or antenna location. >> >> I have several low cost GPS units located in far-from-ideal locations. >> They >> work most of the time but often fade out for minutes at a time. >> >> [This is a poor setup for using the output of a GPSDO to feed other >> measuring >> setups, but it's great for finding corner cases in things like ntpd.] >> >> >> -- >> These are my opinions. I hate spam. >> >> >> >> _______________________________________________ >> 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. -- 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.
