[time-nuts] Arduino GPSDO with 1ns res TIC

Chris Albertson albertson.chris at gmail.com
Thu Feb 13 12:15:43 EST 2014


Graham is correct too.  You can do this all with bare chips. But then you
need to build a PCB.  Lars used the most number of pre-built parts and was
able to make an entire GPSDO using two external chips and did not have to
fabricate a PCB.  I think this is what makes the project so attacive, just
two chips and no PCB and you don't need preprogrammed chips or sen a chip
programmer nor to you need to learn how to use any of this.  Notice in the
photo his circuit mates perfectly with an Arduino's headers and makes a
neat package.

If you have to ask "what chips and how do I program it" then you don't know
enough.  Just spend $29, buy from a first their US distributer and get
identical hardware.  The best reason is then you can ask a question and
"everyone" will have the exact same setup as you.  If is very hard to help
some one who has build a non-standard development system.

Also when some one here make an important, perhaps adding an LCD display
their improvement will apply to your system directly.

But if you want, later move to a cheaper and smaller system.


On Thu, Feb 13, 2014 at 8:49 AM, Graham <planophore at aei.ca> wrote:

> Actually, you don't need an Arduino board to use the Arduino IDE to
> program an Arduino nor do you you need the USB interface to the Arduino
> board to program an Arduino.
>
> For example, you can have a simple Atmega328 circuit with a six or ten pin
> in circuit programming connection (ISP) connected to a programmer, a
> USBtiny for example, the programmer in turn is plugged into your computer
> usb port. You select an appropriate board from the list in the Arduino IDE
> and select a programmer from the programmer list and  from the File menu
> select "Upload using  programmer" and your Arduino like clone will get
> programmed using the programmer. The advantage of this is that you do not
> need a bootloader and will have that bit of program space for your own use.
> You will note that many Arduino boards have a six pin ISP connector on them
> already.
>
> So, what board do you select from the drop down? Depends on how you built
> your circuit, if you used an Atmega328P with a 16MHz external crystal, you
> could select something like the Duemilanove w/Atmega328.
>
> But, the real fun begins when your circuit isn't quite the same as any of
> the listed boards because you can create your own board definition and
> include it in the boards.txt file. For example, an atmega328 using an
> external 20MHz or 10MHz crystal. But wait, it gets better, you can create
> board defintions for Arduino's using other atmel chips like the attiny85
> and attiny2313 and create your program using the same Arduino IDE and many
> of the same libraries and existing sketches and program same through that
> same IDE. What you do loose however is the serial port connection which is
> useful for debugging or whatever BUT you can include serial support in your
> sketch and still have that feature.
>
> Chris is right, the basic Arduino connected through your basic USB cable
> is the simplest why to get started.
>
> cheers, Graham ve3gtc
>
>
>
> On 14-02-13 04:11 PM, Chris Albertson wrote:
>
>> 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.
>>
>>
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-- 

Chris Albertson
Redondo Beach, California


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