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Freescale 9S12 系列单片机应用笔记（SCI）3

时间：11-20 来源：互联网 点击：

  2. pbuf->RingBufTxInPtr=&pbuf->pbuf->RingBufTxInPtr=&pbuf->RingBufTx[0];/*WrapINpointer*/
  3. }
  4. if(pbuf->RingBufTxCtr==1)/*Seeifthisisthefirstcharacter*/
  5. {
  6. SCIEnableTxInt(port);/*Yes,EnableTxinterrupts*/
  7. }
  8. OS_EXIT_CRITICAL();
  9. return(SCI_NO_ERR);
  10. }

    /**

  11. *Toinitializethecommunicationsmodule.
  12. *Youmustcallthisfunctionbeforecallinganyotherfunctions.
  13. */
  14. voidSCIBufferInit(void)
  15. {
  16. SCI_RING_BUF*pbuf;

    pbuf=&SCI0Buf;/*InitializetheringbufferforSCI0*/

  17. pbuf->RingBufRxCtr=0;
  18. pbuf->RingBufRxInPtr=&pbuf->RingBufRx[0];
  19. pbuf->RingBufRxOutPtr=&pbuf->RingBufRx[0];
  20. pbuf->RingBufRxSem=OSSemCreate(0);
  21. pbuf->RingBufTxCtr=0;
  22. pbuf->RingBufTxInPtr=&pbuf->RingBufTx[0];
  23. pbuf->RingBufTxOutPtr=&pbuf->RingBufTx[0];
  24. pbuf->RingBufTxSem=OSSemCreate(SCI_TX_BUF_SIZE);

    pbuf=&SCI1Buf;/*InitializetheringbufferforSCI1*/

  25. pbuf->RingBufRxCtr=0;
  26. pbuf->RingBufRxInPtr=&pbuf->RingBufRx[0];
  27. pbuf->RingBufRxOutPtr=&pbuf->RingBufRx[0];
  28. pbuf->RingBufRxSem=OSSemCreate(0);
  29. pbuf->RingBufTxCtr=0;
  30. pbuf->RingBufTxInPtr=&pbuf->RingBufTx[0];
  31. pbuf->RingBufTxOutPtr=&pbuf->RingBufTx[0];
  32. pbuf->RingBufTxSem=OSSemCreate(SCI_TX_BUF_SIZE);
  33. }

    /**

  34. *Toseeifanycharacterisavailablefromthecommunicationschannel.
  35. *
  36. *@paramport,portcanbeSCI0/SCI1
  37. *@returnIfatleastonecharacterisavailable,thefunctionreturns
  38. *FALSE(0)otherwise,thefunctionreturnsTRUE(1).
  39. */
  40. unsignedcharSCIBufferIsEmpty(unsignedcharport)
  41. {

    #ifOS_CRITICAL_METHOD==3u/*AllocatestorageforCPUstatusregister*/

  42. OS_CPU_SRcpu_sr=0u;
  43. #endif
  44. unsignedcharempty;
  45. SCI_RING_BUF*pbuf;
  46. switch(port)
  47. {/*Obtainpointertocommunicationschannel*/
  48. caseSCI0:
  49. pbuf=&SCI0Buf;
  50. break;

    caseSCI1:

  51. pbuf=&SCI1Buf;
  52. break;
  53. default:
  54. return(0xff);
  55. break;
  56. }
  57. OS_ENTER_CRITICAL();
  58. if(pbuf->RingBufRxCtr>0)
  59. {/*Seeifbufferisempty*/
  60. empty=0;/*BufferisNOTempty*/
  61. }
  62. else
  63. {
  64. empty=1;/*Bufferisempty*/
  65. }
  66. OS_EXIT_CRITICAL();
  67. return(empty);

    }

    /**

  68. *ToseeifanymorecharacterscanbeplacedintheTxbuffer.
  69. *Inotherwords,thisfunctionchecktoseeiftheTxbufferisfull.
  70. *
  71. *@paramport,portcanbeSCI0/SCI1
  72. *@returnIfthebufferisfull,thefunctionreturnsTRUE
  73. *otherwise,thefunctionreturnsFALSE.
  74. */
  75. unsignedcharSCIBufferIsFull(unsignedcharport)
  76. {
  77. #ifOS_CRITICAL_METHOD==3u/*AllocatestorageforCPUstatusregister*/
  78. OS_CPU_SRcpu_sr=0u;
  79. #endif
  80. charfull;
  81. SCI_RING_BUF*pbuf;
  82. switch(port)
  83. {/*Obtainpointertocommunicationschannel*/
  84. caseSCI0:
  85. pbuf=&SCI0Buf;
  86. break;

    caseSCI1:

  87. pbuf=&SCI1Buf;
  88. break;

    default:

  89. return(255);
  90. }
  91. OS_ENTER_CRITICAL();
  92. if(pbuf->RingBufTxCtr
  93. full=0;/*BufferisNOTfull*/
  94. }else{
  95. full=1;/*Bufferisfull*/
  96. }
  97. OS_EXIT_CRITICAL();
  98. return(full);
  99. }

  100. //ThisfunctioniscalledbytheRxISRtoinsertacharacterintothereceiveringbuffer.
  101. staticvoidSCIPutRxChar(unsignedcharport,unsignedcharc)
  102. {

    SCI_RING_BUF*pbuf;

    switch(port)

  103. {/*Obtainpointertocommunicationschannel*/
  104. caseSCI0:
  105. pbuf=&SCI0Buf;
  106. break;

    caseSCI1:

  107. pbuf=&SCI1Buf;
  108. break;

    default:

  109. return;
  110. }
  111. if(pbuf->RingBufRxCtr
  112. pbuf->RingBufRxCtr++;/*No,incrementcharactercount*/
  113. *pbuf->RingBufRxInPtr++=c;/*Putcharacterintobuffer*/
  114. if(pbuf->RingBufRxInPtr==&pbuf->RingBufRx[SCI_RX_BUF_SIZE]){/*WrapINpointer*/
  115. pbuf->RingBufRxInPtr=&pbuf->RingBufRx[0];
  116. }
  117. (void)OSSemPost(pbuf->RingBufRxSem);/*Indicatethatcharacterwasreceived*/
  118. }
  119. }

  120. //ThisfunctioniscalledbytheTxISRtoextractthenextcharacterfromtheTxbuffer.
  121. //ThefunctionreturnsFALSEifthebufferisemptyafterthecharacterisextractedfrom
  122. //thebuffer.ThisisdonetosignaltheTxISRtodisableinterruptsbecausethisisthe
  123. //lastcharactertosend.
  124. staticunsignedcharSCIGetTxChar(unsignedcharport,unsignedchar*err)
  125. {
  126. unsignedcharc;
  127. SCI_RING_BUF*pbuf;

    switch(port)

  128. {/*Obtainpointertocommunicationschannel*/
  129. caseSCI0:
  130. pbuf=&SCI0Buf;
  131. break;

    caseSCI1:

  132. pbuf=&SCI1Buf;
  133. break;

    default:

  134. *err=SCI_BAD_CH;
  135. return(0);
  136. }
  137. if(pbuf->RingBufTxCtr>0){/*Seeifbufferisempty*/
  138. pbuf->RingBufTxCtr--;/*No,decrementcharactercount*/
  139. c=*pbuf->RingBufTxOutPtr++;/*Getcharacterfrombuffer*/
  140. if(pbuf->RingBufTxOutPtr==&pbuf->if(pbuf->RingBufTxOutPtr==&p

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