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???
02/13/06 09:14
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 		 #109826 - Re: SW-I2C efficiency
Responding to: ???'s previous message
Erik Malund said:
I can see many cases where "canned code", even if a bit less efficient than custom, can have a place, but bit-bang is a true processor time hog which put it in a totally different class.



On all my applications the SW-I2C cost only 1% or less of CPU time. So changing to HW-I2C will give no noticeable speed improvement.

I think, this should almost always be the case, that I2C was only a small task beside many others.


Maybe, if tons of PCF8574 are connected and you want to do SW-SPI over the PCF8574, then HW-I2C may be needed. But I have never seen such a crazy approach.


Efficiency was not an absolute value, it can only be calculated in comparison to all other used resources. Thus in typical applications all functions with 1% or less CPU time consumption are efficient enough.


Peter


List of 35 messages in thread
TopicAuthorDate
I2C bit banging            01/01/70 00:00      
   It has I2C bus            01/01/70 00:00      
      question, language and added info            01/01/70 00:00      
         SMB more reliable?            01/01/70 00:00      
            I never hung            01/01/70 00:00      
               Hanging I2C            01/01/70 00:00      
                  No LCD drivers, no hotplug            01/01/70 00:00      
                  Hanging I2C, and freeing it again            01/01/70 00:00      
                     Me too!            01/01/70 00:00      
                        which confirm            01/01/70 00:00      
                           So you've never had to            01/01/70 00:00      
                              I tend to fix hardware shortcomings with            01/01/70 00:00      
                                 Like I said, lucky.            01/01/70 00:00      
                                    doing the impossible            01/01/70 00:00      
                                       Even a nice word for it!            01/01/70 00:00      
                              Look at the philips I2C bus muxes            01/01/70 00:00      
                                 That would make sense            01/01/70 00:00      
            No            01/01/70 00:00      
               For hot plug use SMB            01/01/70 00:00      
               differences SMB IIC            01/01/70 00:00      
   I2C with hang recovery            01/01/70 00:00      
    I2C bit banging: yes !            01/01/70 00:00      
      I see nobody "fighting"            01/01/70 00:00      
         Re Erik            01/01/70 00:00      
            WHO, in his/her right mind would use pol            01/01/70 00:00      
               Really ?            01/01/70 00:00      
                  never used the 552            01/01/70 00:00      
                     HW-I2C not identical !            01/01/70 00:00      
                        where did you gtet that impression?            01/01/70 00:00      
                           Nice            01/01/70 00:00      
                           Re: SW-I2C efficiency            01/01/70 00:00      
                              then the question is "when"            01/01/70 00:00      
                                 No illnes seen until today            01/01/70 00:00      
                                    well, I can't            01/01/70 00:00      
            Good point            01/01/70 00:00      

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