On Thu, 15 Mar 2012 22:27:53 +0000
"Poul-Henning Kamp" <p...@phk.freebsd.dk> wrote:

> If I, based on my design, were to design a gadget for doing VLF
> time-nuts stuff, it would be:
> Floating Input trafo with center-tap for powering antenna
> 16 bit 1MSPS ADC
> ARM chip 
> 10MHz clock input
> 1PPS sync input
> 1PPS sync output
> (DAC output for {Rb|Ocxo}DO use ?)

How good would that DAC need to be?

> 1-4MB RAM

over a 256kB RAM it's get pretty thin if you want to stay in the uC
busines. Unless you want to use an ARM9 or better with external SDRAM
and Flash. But those are mostly BGA (very few QFP chips out there) and
they are assumed to run Linux or Windows CE on them... Support for bare
metal stuff is pretty thin.

On the other hand, if you dont have to support an OS and work on the
bare metal, you can get away with very little RAM. 128k is a damn lot
if you have to fill it with usefull data structures ;-)

> USB2 interface 

Which would mean you need a pretty recent chip as HighSpeed USB has not
been introduced into the uC world for more than 2 years or so.

                        Attila Kinali

Why does it take years to find the answers to
the questions one should have asked long ago?

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