[DSP-10] ver380

[Bob Larkin]

Hi Luis,

The 9600 serial baud rate is locked in tightly to the architecture.  The 
AD21xx handles a single interrupt very well.  But, it is awkward with 
multiple interrupts, in part because there are only two sets of registers 
that can be switched simply.  So to keep things manageable, the 9600 is 
derived by dividing the 48K rate for the CODEC by 5.  Then the same clock 
runs the UART and everything else.

I believe the higher baud rates would require running the ADI style of UART 
which runs off a timer. This then needs two interrupts.  All possible, but 
not simple.  The DSPx would probably have the added power to support a 
faster rate, but the EZKit is running out of "real time."

Another, again not trivial approach, would be to connect up a UART as a 
piece of hardware.  That might make sense.

I have certainly had times when the 9600 seem restrictive.  On the other 
hand, it is also easy to grow in all directions, like bandwidth and dynamic 
range, in which case it becomes a different radio ;-)

Good things to think about, though.

73, Bob  W7PUA


At 03:00 AM 1/12/2009 +0000, Luis Cupido wrote:
>Bob,
>
>How difficult it is to put the DSP working at
>38400b/s or 96800b/s on the serial port ?
>
>Would you think the mumber of packets could
>be increased to 5 to 10 spectral updates per second ?
>Or is there another impediment?
>
>Just dreaming out loud ;-)
>
>Luis Cupido.
>ct1dmk.
>
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