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Jim Granville
05/17/12 20:12
Read: 557 times

#187405 - Other solutions
Responding to: Jason Arkwright's previous message
Jason Arkwright said:
..implemented in a ATmega48 running overclocked at 32MHz, works great but for 8 bits resolution I can get up to 2KHz sine.

If you are already in AVR, did you look at the XMEGAs ?
Only a small jump from Mega48 in SW terms, and they have 12b DACS and plenty of RAM.

Or, if you _really_ want high performance Sine saves, try something like this

That has 108dB precision Audio DACS, and a DSP all in one package.

One way to get higher precision, (smaller steps) in a Fixed Frequency generate, is to vary the samples per cycle.
(that does need new table calculates for each frequency)

If you assume a 1KHz sine from a 1000 sample scan, that same 1MHz rate can generate 999Hz with a 1001-baseline scan, and 1001 Hz with 999-baseline scan
Give the scan more memory, for 10 whole cycles in 10k samples, and now you can resolve to 0.1Hz, with no jitter.

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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