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Per Westermark
10/31/11 16:05
Read: 426 times

#184494 - There _may_ be a solution - but maybe not acceptable
Responding to: Konstantinos L. Angelis's previous message
Konstantinos L. Angelis said:
Since all this analysis is made, the solution is just before your eyes.

Sounds like you are still missing that the solution implies a low transfer speed (which may not be compatible with the OP:s needs) or a master that has a significant pause between slave select and data transfer, and a slave that will not do anything else while the slave-select is activated (which may also not be compatible with the OP:s needs).

So no, while there may be a solution to the problem, there may not be a solution available that can be used by the OP.

Only a hw implementation can do high speed and let the processor perform other tasks concurrently. Any program that requires concurrent operation must give up transfer speed, or concurrent operation (and have a master with manual drive of slave select). That is why there can not be any general solution to the SPI slave problem, using any software implementation. There must be compromises made, and not all projects can accept such compromises.

List of 20 messages in thread
SPI Slave in 89S52      Alexandre Marques      10/30/11 13:35      
   Get real processor      Per Westermark      10/30/11 14:29      
      Topic Author Date      Alexandre Marques      10/30/11 14:46      
         Big problem      Per Westermark      10/30/11 16:01      
         Look for a different model      David Prentice      10/30/11 18:31      
         Try 8051 BASCOM      KONSTANTINOS L. ANGELIS      10/31/11 05:37      
            at what speed      Erik Malund      10/31/11 07:06      
               Interpreters have an easier life.      Per Westermark      10/31/11 08:54      
               Soft SPI speed      KONSTANTINOS L. ANGELIS      10/31/11 09:31      
                  But how to combine that loop with a real program?      Per Westermark      10/31/11 09:44      
                     and more      Erik Malund      10/31/11 09:51      
                        Software master trivial - slave is not      Per Westermark      10/31/11 10:52      
                           SPI analysis is made, results?      KONSTANTINOS L. ANGELIS      10/31/11 14:43      
                              There _may_ be a solution - but maybe not acceptable      Per Westermark      10/31/11 16:05      
                  sure, and so what?      Erik Malund      10/31/11 09:47      
                     SPI at 100Kbps      KONSTANTINOS L. ANGELIS      10/31/11 16:51      
                        Still gives puny transfer rate with significant limitations      Per Westermark      11/01/11 01:05      
                           the answer is      Erik Malund      11/01/11 06:37      
   Fully Interlocked Handshaking.      Michael Karas      11/01/11 08:01      
      Quite common      Per Westermark      11/01/11 08:52      

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