[time-nuts] Do we need something like this ?

Javier javier at nebulosa.org
Sun Jun 12 16:49:59 EDT 2005


I would use a Netburner MOD-5272 or something similar with an embedded 
linux, and add a NTP server. I've ported uClinux 2.6.11 kernel to a 
MOD-5272 and it is really a nice machine, with a Coldfire 66MHz MCF5272 
CPU, 8Mb on RAM and 2Mb on flash, all the MCF5272 available outside, and 
is not very expensive compared with the Beck SC12 (112 EUR compared with 
the 89 EUR for the SC12). Of course, uClinux is not a real time OS and 
the 5272 has no MMU... but if the pll loop uses a timer interrupt,  I 
think that there is no real necessity for a real time OS.


Javier, EA1CRB

Ulrich Bangert wrote:

>4) A Beck SC12 microcontroller. Most possibly you have not heard about
>it because it is a German product. Google for "Beck" and "SC12" to learn
>more about it. Imagine a part with a DIL-32 footprint that contains a 20
>MHz clocked 80186, a lot of flash memory, a interrupt controller, 2
>UARTs, a network controller with a ethernet interface and some other
>goodies. The part comes with a DOS like real time operating system and
>Borland C or Borland Pascal 7 is used to write programs for it. As if
>this alone were not astonishing enough, the part comes with a built in
>web server (!) a built in FTP server (!) and a built in Telnet server
>(!), you name it. Due to the multitasking environment all this stuff
>runs concurrent and parallel to your own application. The gate array
>works as a memory mapped i/o device on the controller's bus. The
>application software is a 80 K byte Pascal program. Regulation is done
>by means of a digital pll. The pll's natural time constant can be set
>from seconds to days and a pre-filter for the samples having 1/6 the
>time constant of the pll's natural time constant can be switched on/off.
>If that reminds you to something you remember about the Stanford
>Research PRS10 loop: Not by chance! All (and i mean really all)
>parameters of the regulation are stored in a non-volatile ram on a
>second-by-second base. I case of power loss these values are loaded back
>at restart, so chances are, you still have a "lock condition" after
>restart if only the LO has a UPS. Regulation can even be switched off,
>giving you a open-loop system that is ideal to characterize the LO and
>to determine the integration time constant that is ideal for this
>specific LO and gps receiver combination. 

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