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???
12/23/10 23:37
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#180271 - Cross talk
Responding to: ???'s previous message
For many projects (doesn't matter what processor), I have been manually stepping the source and have the processor generate an interrupt when the conversion is done. But I do two conversions from each input and keeps the second conversion, just since the first conversion after switching input isn't always good.

In some situations, the data uses an external MUX and it takes too long for the data to stabilize after switching. But even with internal MUX, I tend to see a bit of a problem getting the signal to stabilize. It might be capacitances inside the chip. Or maybe the load is varying slightly on the ADC input. But anyway, throwing the first sample after a switch tends to give better results. Alas, it drops the maximum conversion speed by a factor 2. And I have to get one interrupt/conversion instead of possibly one interrupt after all inputs have been scanned.

List of 103 messages in thread
TopicAuthorDate
Migrating to AVR            01/01/70 00:00      
   8051-replacement            01/01/70 00:00      
      Yep, I agree            01/01/70 00:00      
         Toolchain            01/01/70 00:00      
            free compilers            01/01/70 00:00      
               GCC            01/01/70 00:00      
               Free ARM compilers            01/01/70 00:00      
                  "Free" vs "Free"            01/01/70 00:00      
   faster '51 derivatives in DIL/PLCC & availability            01/01/70 00:00      
      Tired of hanging around with 5 mips            01/01/70 00:00      
         Re: Tired of hanging around with 5 Mips            01/01/70 00:00      
            experiences prototyping with smd's            01/01/70 00:00      
               Prototype SMD            01/01/70 00:00      
            Nice, but where to buy and how much?            01/01/70 00:00      
               Re: where to buy and how much?            01/01/70 00:00      
                  Yeah, but....            01/01/70 00:00      
                     I agree            01/01/70 00:00      
                        re the XA            01/01/70 00:00      
                     How many 51' compilers make use of the 51's dual DPTR            01/01/70 00:00      
               You must live on a very interesting corner!            01/01/70 00:00      
                  Ha,ha, AVR are ubiquitus            01/01/70 00:00      
                     HUH??            01/01/70 00:00      
                        Lies, Damned Lies, and Statistics            01/01/70 00:00      
                           I think            01/01/70 00:00      
                        'F120            01/01/70 00:00      
                           "bunchload"            01/01/70 00:00      
                              re: bunchload            01/01/70 00:00      
                                 Youse guys in Old Blightly            01/01/70 00:00      
         Prototyping SMD's            01/01/70 00:00      
            Hand-made PCBs with hand-soldered SMDs            01/01/70 00:00      
            SMD's            01/01/70 00:00      
               Well, that's nice, but not necessary.            01/01/70 00:00      
            a very general - and accurate - comment ...            01/01/70 00:00      
               apprehension            01/01/70 00:00      
   nearby            01/01/70 00:00      
      'jumping' from the '51            01/01/70 00:00      
         AVR update            01/01/70 00:00      
            the chip does not crash            01/01/70 00:00      
               Lockup etc            01/01/70 00:00      
                  increase the clock until lockup            01/01/70 00:00      
                     undefined behaviour            01/01/70 00:00      
                     NO, they do not recommend it            01/01/70 00:00      
                        simultaneous posts            01/01/70 00:00      
                           Overclocking            01/01/70 00:00      
                     This is simply an error in judgment            01/01/70 00:00      
                        all bets are off            01/01/70 00:00      
                     overclocking            01/01/70 00:00      
                        Yeah, okay            01/01/70 00:00      
                           Neeed for speeed            01/01/70 00:00      
                              Because of this...            01/01/70 00:00      
                                 Missing the point            01/01/70 00:00      
                                    missing the point?            01/01/70 00:00      
                                       Modern derivatives            01/01/70 00:00      
                                 hogwash            01/01/70 00:00      
                                 I'm not sure you're on track here ...            01/01/70 00:00      
                                    Hi Richard            01/01/70 00:00      
                                       the problem with AVR's is that they're ATMEL only            01/01/70 00:00      
                                          That's one general and one personal problem            01/01/70 00:00      
                                             Yes, that's what it is ...            01/01/70 00:00      
                                                Second source not so important anymore            01/01/70 00:00      
                                                   It's not as convenient now as it once was            01/01/70 00:00      
                                                      Free tools only have investment in knowledge            01/01/70 00:00      
                                                         again. Per            01/01/70 00:00      
                                                            Not at all            01/01/70 00:00      
                                                         it's not just the tools            01/01/70 00:00      
                                                            "Best code"            01/01/70 00:00      
                                                               There are too many definitions of "best"            01/01/70 00:00      
                                                               Don't go for best            01/01/70 00:00      
                                                   yes and no            01/01/70 00:00      
                                                   Single-source chips vs single-source architecture            01/01/70 00:00      
                                 cross purposes            01/01/70 00:00      
                                    DSP PROCS            01/01/70 00:00      
                                       gp ahead, stay behind the curve            01/01/70 00:00      
                                          Got to disagree there,...            01/01/70 00:00      
                                             I do not consider 'luck' a design parameter            01/01/70 00:00      
                                             Flying leads            01/01/70 00:00      
                                       re: DSP PROCS            01/01/70 00:00      
                           100MHz 32-bit ARM            01/01/70 00:00      
                              The Trap...            01/01/70 00:00      
                                 talking out of both sides of the mouth            01/01/70 00:00      
                                 "on the DSP level"            01/01/70 00:00      
                                    Often hand-optimized assembler available            01/01/70 00:00      
                                    Misunderstood me            01/01/70 00:00      
                                       Cross talk            01/01/70 00:00      
                                       What kind            01/01/70 00:00      
                                       nobody has suggested            01/01/70 00:00      
                           no, you are not            01/01/70 00:00      
                           there are '51s with MACs            01/01/70 00:00      
                              and...            01/01/70 00:00      
                                 yes and            01/01/70 00:00      
                                 He wants Plastic Dips            01/01/70 00:00      
                                    very few and            01/01/70 00:00      
                                    the 33 mips DS89C450 is in DIP if you want            01/01/70 00:00      
            no such thing as "Best"            01/01/70 00:00      
               '51 weaknesses outweigh the AVR            01/01/70 00:00      
                  similiar            01/01/70 00:00      
                  Quite so            01/01/70 00:00      
                     3, 4, 5            01/01/70 00:00      
                        Horses for courses            01/01/70 00:00      
                  Have you considered using a DSP?            01/01/70 00:00      
   I'll be off too, but not to AVR            01/01/70 00:00      
      A Guess            01/01/70 00:00      
         Low volume            01/01/70 00:00      

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