Chris BAYLEY / Mbed 2 deprecated SPI-2-USB

Dump SPI from input to pc.serial

Dependencies:   mbed

tinyQ.h@0:1ca47c273d0f, 2012-01-30 (annotated)

Committer:
cbayley
Date:
Mon Jan 30 23:08:52 2012 +0000
Revision:
0:1ca47c273d0f

        

        
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cbayley

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/** \defgroup tinyQ Tiny Queue





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 * Tiny Queues implements a 4 byte queue for iPhone events with just 1 byte of management overhead.





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 * Head and Tail pointers both inherently wrap at the end of the buffer and no bounds checking is 





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 * necesary IFF the buffer size is set as a power of 2 equal to the width of the pointers !!





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 * i.e head is 2 bits wide so the buffer must be 2^2 = 4 bytes deep.





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 * @{





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 */





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/** NOTE: Q_SIZE MUST be == 2 ^ widthof( tinyQ_t.head ) */





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#define Q_SIZE 256





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/** a tinyQ tracks a 4 byte queue with just 1 byte overhead */





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typedef struct





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{





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    unsigned int head:8;  ///< the bit depth MUST be that power of 2 that is the Q_SIZE





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    unsigned int tail:8;  ///< the bit depth MUST be that power of 2 that is the Q_SIZE





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    unsigned int fill:9;  ///< Must be 1 bit bigger than the head and tail pointers





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    char data[Q_SIZE];     ///< NOTE: Q_SIZE MUST be == 2 ^ widthof( tinyQ_t.head )





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}tinyQ_t;





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/**





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 * \brief Push an Accessibility Event onto our queue for sending to the iphone





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 * \param q pointer to our tinyQ_t





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 * \param c the Event to send to the iphone





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 * \return null if Q full,  1 on success





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 * \sa Qpop(), Qjump()





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 * \ingroup tinyQ





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 */





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int Qpush( tinyQ_t* q, char c );





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/**





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 * \brief Pop an Accessibility Event off our queue for sending to the iphone





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 * \param q pointer to our tinyQ_t





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 * \param c pointer to receive the Event





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 * \return null if Q empty, 1 on success





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 * \sa Qpop(), Qjump()





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 * \ingroup tinyQ





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 */





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int Qpop( tinyQ_t* q, char * c);





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int Qfree( tinyQ_t* q );





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void Qinit( tinyQ_t* q );