[time-nuts] Simple open source microcontroller solution to tune DDS needed

[Bob Bownes]

The digispark and digispark pro are also some nice <$15 development boards
that are USB programmable, use the Arduino IDE or AVR compiler, and have
just enough pins to be useful.

On Wed, Dec 13, 2017 at 4:34 PM, jimlux <jimlux at earthlink.net> wrote:

> On 12/13/17 1:28 PM, Jerry Hancock wrote:
>
>> Well, if you haven’t selected a DDS and you need I/Q, I would go with the
>> tried and true 9854 as it has I/Q outputs and I thought a 12bit DAC so the
>> resulting spurs and sfdr are lower than other chips, or were, as I think
>> they have 14bit DACs on other chips now.  It also depends on the highest
>> frequency range needed and power requirements as they all seem to run hot.
>> There is a new DDS, a 9910 I think, that uses a 14bit DAC but it is a
>> single output and would need to sync clocks if you need I/Q.  I have used
>> the 9854 with PIC, Arduino and STM32 and assuming the frequency range is
>> ok, I found it to be the better of the chips.  I don’t think they have a
>> replacement for it (I/Q with 14bit DAC would be great) but I haven’t looked
>> lately.
>>
>> The language is C but I think it has C++ and C# compilers out there.
>> Also, once you have the code tested on the Arduino you can just run it on
>> the equivalent AVR chip and build your own board.  I don’t think there is a
>> license or runtime compiler issue and if there is, I remember seeing a GNU
>> compiler for the AVRs and Arduino.  My only point is that for prototyping
>> and testing, the Arduino seems to be the easiest with tons of support and
>> many, many adapters and I/O,  The STM32 boards are faster but the learning
>> curve is just unbelievable.  It took me months to master those boards
>> compared to minutes for the Arduino.
>>
>>
>
> I agree - $20 for a Teensy, some jumper wires from solder holes on the
> Teensy to your breadboard, load up the Teensyduino libraries into the
> Arduino IDE and your SPI/I2C/serial interface is done.  I did this to write
> arduino code to drive a Silabs part.
>
> If it takes an hour, I'd be surprised (or you have an incredibly slow
> download connection, like doing it on an airplane in the back rows where
> the WiFi is clunky - which I have done).  The hard part when going to a
> standalone design is picking the right pins on the microcontroller (since
> so many have multiple functions, you want to be careful about accidentally
> using something that has another useful function).
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/m
> ailman/listinfo/time-nuts
> and follow the instructions there.
>