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project:journal [2007/04/27 00:21]
127.0.0.1 external edit
project:journal [2009/09/01 10:04] (current)
robm Correcting instruction duration calculations
Line 96: Line 96:
   * PIC datasheets says every (assembly) instruction takes a single cycle (except program branches which are 2)   * PIC datasheets says every (assembly) instruction takes a single cycle (except program branches which are 2)
   * Running at 4MHz = 4,000,000Hz   * Running at 4MHz = 4,000,000Hz
-  * Each single instruction takes 1/4,000,000 seconds, which is 250ns+  * Each oscillator cycle takes 1/4,000,000 seconds, which is 250ns 
 +  * Each instruction takes 4 cycles (except branches, which are 8), which is 1us or 2us respectively. 
 +    * (Thanks to Christoph for pointing this out by email)
   * Hence even if I was doing this in assembly, speed would still not be an issue   * Hence even if I was doing this in assembly, speed would still not be an issue
  
project/journal.txt · Last modified: 2009/09/01 10:04 by robm