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Michael Karas
05/17/12 15:58
Read: 557 times
Beaverton Or

#187404 - 'F120 Series
Responding to: Erik Malund's previous message
Erik Malund said:
Have you considered the SILabs C8051F120 running 1 clock at 100MHz?

This is actually a great idea. The 'F120 series have _two_ 12-bit D/As.

At 100MHz clocking rate it would be hard to believe that you could not achieve nice sine waves at 10-20KHz on the two channels simulteneously.

The 'F120 series D/A converters have a timer driven update mode to give accurate jitter free strobe times. When using this timer mode you can setup to get a software interrupt that occurs right after the D/A update. In the service routine the software quickly updates the D/A data registers where the data is held till the next timer update. To operate two channels set them up to update off the same timer channel. Then a single interrupt routine can be used to setup the D/A data registers for both of the channels.

The maximum sine wave frequency is limited by the frequency of the D/A update timer divided by the number of samples in the sinewave look up table. Of course the maximum frequency is also throttled by how quckly the interrupt service routine can get in, update the D/A registers. increment the look up table pointer(s) and then get out of the ISR.

Michael Karas

List of 24 messages in thread
256bit x 8 proms      Jason Arkwright      05/15/12 04:44      
   What frequency Sine wave & Clock ?      Jim Granville      05/15/12 05:37      
      Thank you      Jason Arkwright      05/15/12 08:10      
         DDS (Direct Digital Synthesis)      Jim Granville      05/15/12 17:49      
         digital sine wave      Andy Peters      05/16/12 21:24      
            uC sine generator      Jason Arkwright      05/17/12 04:36      
               DMA      Aubrey Kagan      05/17/12 06:43      
               neither do I      Erik Malund      05/17/12 07:07      
                  ARN      Michael Karas      05/17/12 15:30      
                  'F120 Series      Michael Karas      05/17/12 15:58      
               Other solutions      Jim Granville      05/17/12 20:12      
               150nS access time is so long      Justin Fontes      05/17/12 22:13      
            is that realy the case?      Richard Erlacher      05/23/12 16:21      
   Of course my solution      Jez Smith      05/19/12 09:11      
      Hmmm.., nice but...      Jason Arkwright      05/20/12 12:29      
         Those are actually PALs not CPLDs      Jez Smith      05/20/12 12:44      
         ATF750CL for PT clocks      Jim Granville      05/20/12 16:38      
            ATF750      Jason Arkwright      05/21/12 09:21      
               ATF750C ?      Jim Granville      05/22/12 23:42      
                  Yes, Jim You are exactly right.      Jason Arkwright      05/26/12 12:49      
                     Can I suggest      Jez Smith      05/26/12 14:00      
                     ATDH1150USB      Jim Granville      05/26/12 19:45      
                        Update : ATDH1150VPC      Jim Granville      05/27/12 05:57      
                        Thanks JIM      Jason Arkwright      05/31/12 15:57      

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