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???
10/25/10 08:38
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#179320 - Use correct capacitor values.
Responding to: ???'s previous message
Tejas H S said:
circuit:
http://ubuntuone.com/p/Lzy/

(Is there an free software using which such circuits can be drawn, as drawing these things using paint like programs is very laborious.)


Your schematic shows 22nF (22000pF) capacitors in the XTAL circuit. Even if you have not got schematic software, it is essential that you add a note to describe the error.

I have never used a P89V51xxx chip. From my FLASHMAGIC docs, it seems to just use RST to enter bootloader. It is your job to read your data sheets.

I have used a P89C51RD2. This uses /PSEN and RST to enter the bootloader.

Quite honestly, you should download the data sheet, app notes, etc.
Then implement any schematics precisely. Using components that are 1000X the recommended values is unwise.

By all means ask about how to calculate values. You will probably be given 'Rule of Thumb' methods. e.g. use 22pF for XTAL, 10nF for decoupling, 100uF for reservoir ...
Do not be proud. Copy working designs. Ask...

In electronics, these 'Rule of Thumb' values will probably still work at 10X or even 1/10. You can always calculate them properly with the help of a cigarette packet.

Incidentally, your original AT89S52 chip can be programmed by many different pieces of software. However you MUST construct the RS232 i/f or LPT i/f exactly to the recommendations. Cutting corners is guaranteed to give you unreliability and often failure.

David.


List of 40 messages in thread
TopicAuthorDate
need help getting started with AT89S52            01/01/70 00:00      
   Buy programming "cable" from Atmel            01/01/70 00:00      
      Is it Parallel Port given in there            01/01/70 00:00      
         Wrong path            01/01/70 00:00      
            path suggestions            01/01/70 00:00      
               using P89V51RD2            01/01/70 00:00      
                  FlashMagic            01/01/70 00:00      
         Make it happen...            01/01/70 00:00      
            have a look at this one            01/01/70 00:00      
         COM1 will do            01/01/70 00:00      
            ISP circuit for P89v51rd2            01/01/70 00:00      
               not informative            01/01/70 00:00      
                  how about this one            01/01/70 00:00      
                     how about where are the capacitors            01/01/70 00:00      
                        about deviation from topic            01/01/70 00:00      
                           not useable            01/01/70 00:00      
                              wiht names for pins of caps            01/01/70 00:00      
                                 Chat forum            01/01/70 00:00      
                                 Use correct capacitor values.            01/01/70 00:00      
                                    more wrong caps            01/01/70 00:00      
                                       capacitor values            01/01/70 00:00      
                                          what about the plug??            01/01/70 00:00      
                                             i dont get you            01/01/70 00:00      
                                                no - maybe            01/01/70 00:00      
                                       What is worse?            01/01/70 00:00      
                                          The main objective of communications            01/01/70 00:00      
                                             reasons for not using max 233            01/01/70 00:00      
                                                Cost?            01/01/70 00:00      
                                                Well, I search for you and I found...            01/01/70 00:00      
                                          this            01/01/70 00:00      
                                             errors from over-filtering?            01/01/70 00:00      
                                             it's a linear error?            01/01/70 00:00      
                                                Don't introduce "linear" in the equation            01/01/70 00:00      
                                                   The original question was not answered            01/01/70 00:00      
                                                      'worse' is not an absolute word            01/01/70 00:00      
                                                         It's not ridiculous            01/01/70 00:00      
                                                            Don't try to redefine the purposes of old posts.            01/01/70 00:00      
                                                      Still no linearity claimed. Just "more out of spec bader"            01/01/70 00:00      
                                                         Not obvious            01/01/70 00:00      
                                                            I agree            01/01/70 00:00      

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