ComputerVoltageSources

Dave,

Take a look at this:
http://www.sparkfun.com/commerce/product_info.php?products_id=99#

Yes, you could build one pretty cheap but this is plug 'n play and 
pretty cheap already (no building required).

Besides adding an I2C realtime clock w/ battery backup to the AtomPRO 
that should stay accurate to within 1 minute per month (~20ppm 
accuracy), it has a 1Hz output pin (square wave) that could be used 
as a timing pulse to syncronize multiple AtomPROs.

Also, if you really want to go nuts... one could remove the 
oscillator, the two caps, and one resistor from the AtomPro and use 
an external clock source (such as a frequency generator synced with a 
cesium frequency standard) to the OSC1 pin on the H8/3664.  See page 
69 in the H8/3664 datasheet for details on using an External Clock 
Input.  

One thing I did notice was that the datasheet shows when not using a 
Subclock, X1 connected to VCL or VSS yet on the AtomPRO schematic is 
shows them both as not connected to anything.  I wonder if this could 
cause some drift issues.  Thoughts?

Best regards,
Brice


--- In ComputerVoltageSources@yahoogroups.com, "djbrow54" 
<davebr@...> wrote:
>
> Tell me more about the timing requiremetns.  In looking at 
> metronomes, "highly accurate" is described as +/- 1%.  The PSIM is 
> better than that.  In a 5 minute musical piece, 1% accuracy would 
be 
> 3 seconds.  0.1% would be 300 mS.  I don't know the exact accuracy 
> of the PSIM since I don't know the resonator used but it is 
probably 
> well less than the 1%.
> 
> Is this something that MIDI timing clocks could be used for?  If 
> MIDI could be used as a master clock, it would be easy to build a 
> reference timebase.  My first MIDI code implemented an interrupt 
> routine for input.  I later adopted to the HSERIN command which 
> buffers the data.  Going back to my original code, I could use real 
> time nature of the interrupt to implement a real time clock.  I 
have 
> no relevant experience with MIDI clock and synchronization. It 
would 
> be simple to add and implement, though.  Multiple PSIMs would be 
> synchronized to the same MIDI reference.  In fact, an AVR2313 with 
a 
> crystal and two resistors could be used to generate such a 
> reference.  Might be a nifty accessory.
> 
> Dave
> 
> --- In ComputerVoltageSources@yahoogroups.com, "Gary Chang" > The 
> length of Psim Madness is not long in terms of music duration -
> > any typical piece of music is much longer than that.  Honestly, a 
> high
> > school music student has a better sense of time than the PSIM.  
> > 
> > INHO, ability to slave the PSIM is essential.
> > 
> > If these devices can't play 16 bars together with something else, 
> it's
> > pretty much useless as a sequential pitch source....  except for a
> > phasing minimalist piece (such as PSIM madness).
> > 
> > 
> > gary
>