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???
02/14/05 00:54
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 		 #87302 - 15 seconds? !!!
Responding to: ???'s previous message
If you are processing a single bar scan wherein you are adding one new graphic pixel column and moving the scanning cursor over one column to the right on a 240x128 display I compute:

((15 sec)/(240 col))/(128 pix/col) = 488 usec / pixel

You must have something significantly wrong someplace. Even with a read/modify/write approach to operating the display each pixel takes a SET_MEM_ADDR command (make sure auto increment is off), READ_DATA command, merge in new pixel (AND & OR), followd by WRITE_DATA command.

Your SiLabs part at 22.1184 MHz operates with machine cycles of 45.2 ns !! Somehow you are managing to burn up 488 us / 42.5 ns = 11482 machine cycles per pixel. Something is clearly not meshing like a new set of gears here.

Michael Karas


List of 42 messages in thread
TopicAuthorDate
GLCD Project (low frequency scope)            01/01/70 00:00      
   GLCD Scrolling            01/01/70 00:00      
      Lesson learned            01/01/70 00:00      
         did you check            01/01/70 00:00      
   hi Speed GLCD displays?            01/01/70 00:00      
      Probably            01/01/70 00:00      
      Hardware scroll            01/01/70 00:00      
         PaceSetter            01/01/70 00:00      
      Best Display >> None is perfect            01/01/70 00:00      
         Sweep mode            01/01/70 00:00      
            Scope Squares            01/01/70 00:00      
            8 Bits Update            01/01/70 00:00      
               like rotate it 90°?            01/01/70 00:00      
                  90° Rotation Indeed            01/01/70 00:00      
   One step further            01/01/70 00:00      
      Animation            01/01/70 00:00      
         scan too slow!!            01/01/70 00:00      
            15 seconds? !!!            01/01/70 00:00      
               or....            01/01/70 00:00      
               slightly more            01/01/70 00:00      
               Optimization            01/01/70 00:00      
                  calculation            01/01/70 00:00      
                     Will have a look            01/01/70 00:00      
                        assembler speedup            01/01/70 00:00      
                  if it is really slow            01/01/70 00:00      
                     too smart Man            01/01/70 00:00      
                        another way            01/01/70 00:00      
                  When do you wait?            01/01/70 00:00      
                     first choice            01/01/70 00:00      
               should I use Serial RAM for buffer?            01/01/70 00:00      
                  serial RAM and time            01/01/70 00:00      
                     lcd_not_busy();            01/01/70 00:00      
                        a much faster approach            01/01/70 00:00      
                           I don't have enough XRAM            01/01/70 00:00      
                              magic            01/01/70 00:00      
                              more tweaking            01/01/70 00:00      
                                 Good thinking Jan            01/01/70 00:00      
                                    tweaking II.            01/01/70 00:00      
                                       Magic Tweeking            01/01/70 00:00      
                  Serial RAM is useless            01/01/70 00:00      
   maybe this technique will work here            01/01/70 00:00      
      Multi-microcontrollers            01/01/70 00:00      

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