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Freescale 9S12 系列單片機(jī)應(yīng)用筆記（SCI）1

作者： 時(shí)間：2016-11-20 來源：網(wǎng)絡(luò) 收藏

SCI模塊應(yīng)用筆記（1）

UART，也就是異步串行通訊接口是單片機(jī)中最常見的外設(shè)，幾乎每種類型的單片機(jī)都必備1到2個(gè)UART接口，9S12系列單片機(jī)也不例外。不過，摩托羅拉給他自己的單片機(jī)的串口起了個(gè)很有個(gè)性的縮寫名稱SCI（serialcommunicationinterface），其實(shí)就是我們常說的UART。

本文引用地址：http://m.butianyuan.cn/article/201611/318823.htm

各種單片機(jī)串口的編程都大同小異，無非就是設(shè)置波特率、起始位、停止位、校驗(yàn)位等等。下面通過給出編程例子的方式分別介紹。

設(shè)置波特率

  1. /**
  2. *SettheBaudRateoftheSCI.
  3. *@paramport,portcanbeSCI0/SCI1
  4. *@parambaudRate,thewantedbaudrate.
  5. *@parambusClk,TheSCImoduleclock.
  6. */
  7. voidSCISetBaudRate(unsignedcharport,unsignedlongbaudRate,unsignedlongbusClk)
  8. {
  9. unsignedshortbaudRateReg;
  10. baudRateReg=(unsignedshort)(busClk/baudRate/16);
  11. if(port==SCI0)
  12. {
  13. //HerewemustwriteBDHfirst!
  14. SCI0BDH=(0x1f&(baudRateReg>>8));
  15. SCI0BDL=(0xff&baudRateReg);
  16. }
  17. elseif(port==SCI1)
  18. {
  19. SCI1BDH=(0x1f&(baudRateReg>>8));
  20. SCI1BDL=(0xff&baudRateReg);
  21. }
  22. else
  23. {
  24. //Somethingmustgowrong.Donothinghere!
  25. }
  26. }

設(shè)置奇偶校驗(yàn)位

  1. /**
  2. *Enable/DisableparityfunctionandsettheParitytype
  3. *@paramportportcanbeSCI0/SCI1
  4. *@paramisEnable0fordisableparityfunction,1forenable
  5. *@paramtype0forEvenParity,1forOddParity
  6. */
  7. voidSCISetParity(unsignedcharport,unsignedcharisEnable,unsignedchartype)
  8. {
  9. if(port==SCI0)
  10. {
  11. SCI0CR1_PE=(isEnable&0x01);
  12. SCI0CR1_PT=(type&0x01);
  13. }
  14. elseif(port==SCI1)
  15. {
  16. SCI1CR1_PE=(isEnable&0x01);
  17. SCI1CR1_PT=(type&0x01);
  18. }
  19. else
  20. {
  21. //Ifcoderunhere,somethingmustgowrong.Donothinghere!
  22. }
  24. }


使能數(shù)據(jù)位的長度

  1. /**
  2. *SettheDataFormatModeBit
  3. *@paramportportcanbeSCI0/SCI1
  4. *@parambitsmustbe8or9
  5. */
  6. voidSCISetDataBit(unsignedcharport,unsignedcharbits)
  7. {
  8. if(port==SCI0)
  9. {
  10. switch(bits)
  11. {
  12. case8:
  13. SCI0CR1_M=0;/*1startbit,8databits,1stopbit*/
  14. break;
  15. case9:
  16. SCI0CR1_M=1;/*1startbit,9databits,1stopbit*/
  17. break;
  18. default:
  19. //Ifcoderunhere,somethingmustgowrong.Donothinghere!
  20. break;
  21. }
  22. }
  23. elseif(port==SCI1)
  24. {
  25. switch(bits)
  26. {
  27. case8:
  28. SCI1CR1_M=0;/*1startbit,8databits,1stopbit*/
  29. break;
  30. case9:
  31. SCI1CR1_M=1;/*1startbit,9databits,1stopbit*/
  32. break;
  33. default:
  34. //Ifcoderunhere,somethingmustgowrong.Donothinghere!
  35. break;
  36. }
  37. }
  38. else
  39. {
  40. //Ifcoderunhere,somethingmustgowrong.Donothinghere!
  41. }
  43. }


設(shè)置串口的工作模式

NORMAL_MODE是我們通常用的模式

LOOP_MODE是自發(fā)自收模式

SING_WIRE_MODE就是收發(fā)公用一條數(shù)據(jù)線的模式

  1. /**
  2. *Settheworkmodeofoperation
  3. *@paramportportcanbeSCI0/SCI1
  4. *@parammodemodecanbeNORMAL_MODE/LOOP_MODE/SING_WIRE_MODE
  5. */
  6. voidSCISetWorkMode(unsignedcharport,unsignedcharmode)
  7. {
  8. if(port==SCI0)
  9. {
  10. switch(mode)
  11. {
  12. caseNORMAL_MODE:
  13. SCI0CR1_LOOPS=0;
  14. SCI0CR1_RSRC=0;
  15. break;
  16. caseLOOP_MODE:
  17. SCI0CR1_LOOPS=1;
  18. SCI0CR1_RSRC=0;
  19. break;
  20. caseSING_WIRE_MODE:
  21. SCI0CR1_LOOPS=1;
  22. SCI0CR1_RSRC=1;
  23. break;
  24. default:
  25. //Ifcoderunhere,somethingmustgowrong.Donothinghere!
  26. break;
  27. }
  28. }
  29. elseif(port==SCI1)
  30. {
  31. switch(mode)
  32. {
  33. caseNORMAL_MODE:
  34. SCI1CR1_LOOPS=0;
  35. SCI1CR1_RSRC=0;
  36. break;
  37. caseLOOP_MODE:
  38. SCI1CR1_LOOPS=1;
  39. SCI1CR1_RSRC=0;
  40. break;
  41. caseSING_WIRE_MODE:
  42. SCI1CR1_LOOPS=1;
  43. SCI1CR1_RSRC=1;
  44. break;
  45. default:
  46. //Ifcoderunhere,somethingmustgowrong.Donothinghere!
  47. break;
  48. }
  49. }
  50. else
  51. {
  52. //Ifcoderunhere,somethingmustgowrong.Donothinghere!
  53. }
  54. }

設(shè)置SCI模塊是否在Wait模式下工作

  1. /**
  2. *Enable/DisabletheSCIinwaitmode
  3. *@paramportportcanbeSCI0/SCI1
  4. *@parammodemodecanbeRUN_MODE/WAIT_MODE
  5. */
  6. voidSCISetPowerMode(unsignedcharport,unsignedcharmode)
  7. {
  8. if(port==SCI0)
  9. {
  10. switch(mode)
  11. {
  12. caseRUN_MODE:
  13. SCI0CR1_SCISWAI=0;
  14. break;
  15. caseWAIT_MODE:
  16. SCI0CR1_SCISWAI=1;
  17. break;
  18. default:
  19. //Ifcoderunhere,somethingmustgowrong.Donothinghere!
  20. break;
  21. }
  22. }
  23. elseif(port==SCI1)
  24. {
  25. switch(mode)
  26. {
  27. caseRUN_MODE:
  28. SCI1CR1_SCISWAI=0;
  29. break;
  30. caseWAIT_MODE:
  31. SCI1CR1_SCISWAI=1;
  32. break;
  33. default:
  34. //Ifcoderunhere,somethingmustgowrong.Donothinghere!
  35. break;
  36. }
  37. }
  38. else
  39. {
  40. //Ifcoderunhere,somethingmustgowrong.Donothinghere!
  41. }
  42. }

使能SCI模塊的接收功能

  1. /**
  2. *Enable/DisableSCIReceiver
  3. *@paramportportcanbeSCI0/SCI1
  4. *@paramisEnable0disable1enable
  5. */
  6. voidSCIEnableRecv(unsignedcharport,unsignedcharisEnable)
  7. {
  8. if(port==SCI0)
  9. {
  10. SCI0CR2_RE=(isEnable&0x01);
  11. }
  12. elseif(port==SCI1)
  13. {
  14. SCI1CR2_RE=(isEnable&0x01);
  15. }
  16. else
  17. {
  18. //Ifcoderunhere,somethingmustgowrong.Donothinghere!
  19. }
  20. }

使能SCI模塊的發(fā)送功能

  1. /**
  2. *Enable/DisableSCITransmitter
  3. *@paramportportcanbeSCI0/SCI1
  4. *@paramisEnable0disable1enable
  5. */
  6. voidSCIEnableTrans(unsignedcharport,unsignedcharisEnable)
  7. {
  8. if(port==SCI0)
  9. {
  10. SCI0CR2_TE=(isEnable&0x01);
  11. }
  12. elseif(port==SCI1)
  13. {
  14. SCI1CR2_TE=(isEnable&0x01);
  15. }
  16. else
  17. {
  18. //Ifcoderunhere,somethingmustgowrong.Donothinghere!
  19. }
  20. }

發(fā)送數(shù)據(jù)

  1. /**
  2. *SendacharthrounghSCImodule.
  3. *@paramportportcanbeSCI0/SCI1
  4. *@paramsthedatatobesent
  5. */
  6. voidSCIPutChar(unsignedcharport,unsignedchars)
  7. {
  8. if(port==SCI0)
  9. {
  10. while(SCI0SR1_TDRE==0);//SCI0SR1_TC是發(fā)送完成
  11. SCI0DRL=s;
  12. }
  13. else
  14. {
  15. while(SCI1SR1_TDRE==0);//SCI1SR1_TC
  16. SCI1DRL=s;
  17. }
  18. }
  20. /**
  21. *SendacharstringthrounghSCImodule.
  22. *@paramportportcanbeSCI0/SCI1
  23. *@param*strthestringtobesent
  24. */
  25. voidSCIPutStr(unsignedcharport,unsignedchar*str)
  26. {
  27. while(0!=*str)
  28. {
  29. SCIPutChar(port,*str);
  30. str++;
  31. }
  32. }
  34. /**
  35. *SenddatathrounghSCImodule.
  36. *@paramportportcanbeSCI0/SCI1
  37. *@param*ppointertothedatatobesent
  38. *@paramsizethesize(byte)ofthedata
  39. */
  40. voidSCIWrite(unsignedcharport,void*p,intsize)
  41. {
  42. unsignedchar*str=(unsignedchar*)p;
  43. while(size>0)
  44. {
  45. SCIPutChar(port,*str);
  46. str++;
  47. size--;
  48. }
  49. }
  51. /**
  52. *Sendashortintvalue(BigEndian)throunghSCImodule.
  53. *@paramportportcanbeSCI0/SCI1
  54. *@paramithedatatobesent
  55. */
  56. voidSCIPutShortBigEndian(unsignedcharport,shorti)
  57. {
  58. char*p=(char*)&i;
  59. SCIPutChar(port,p[0]);
  60. SCIPutChar(port,p[1]);
  61. }
  63. /**
  64. *Sendashortintvalue(LittleEndian)throunghSCImodule.
  65. *@paramportportcanbeSCI0/SCI1
  66. *@paramithedatatobesent
  67. */
  68. voidSCIPutShortLittleEndian(unsignedcharport,shorti)
  69. {
  70. char*p=(char*)&i;
  71. SCIPutChar(port,p[1]);
  72. SCIPutChar(port,p[0]);
  73. }
  75. /**
  76. *Sendalongintvalue(BigEndian)throunghSCImodule.
  77. *@paramportportcanbeSCI0/SCI1
  78. *@paramithedatatobesent
  79. */
  80. voidSCIPutLongBigEndian(unsignedcharport,longi)
  81. {
  82. char*p=(char*)&i;
  83. SCIPutChar(port,p[0]);
  84. SCIPutChar(port,p[1]);
  85. SCIPutChar(port,p[2]);
  86. SCIPutChar(port,p[3]);
  87. }
  89. /**
  90. *Sendalongintvalue(LittleEndian)throunghSCImodule.
  91. *@paramportportcanbeSCI0/SCI1
  92. *@paramithedatatobesent
  93. */
  94. voidSCIPutLongLittleEndian(unsignedcharport,longi)
  95. {
  96. char*p=(char*)&i;
  97. SCIPutChar(port,p[3]);
  98. SCIPutChar(port,p[2]);
  99. SCIPutChar(port,p[1]);
  100. SCIPutChar(port,p[0]);
  101. }


接收數(shù)據(jù)

  1. /**
  2. *ReceiveachardatafromSCImodule,noreply.
  3. *@paramportportcanbeSCI0/SCI1
  4. *@returnthereceivedchar
  5. */
  6. unsignedcharSCIGetChar(unsignedcharport)
  7. {
  8. if(port==SCI0)
  9. {
  10. while(SCI0SR1_RDRF==0);
  11. returnSCI0DRL;
  12. }
  13. else
  14. {
  15. while(SCI1SR1_RDRF==0);
  16. returnSCI1DRL;
  17. }
  18. }

相應(yīng)的頭文件

  1. /**
  2. *filesci.h
  3. *authorLiYuan
  4. *platform:mc9s12dp256B
  5. *date:2012-4-16
  6. *version:1.0.0
  7. *description:SCI(SerialCommunicationInterface)SupportCode
  8. */
  10. #ifndef_SCI_H_
  11. #define_SCI_H_
  14. #defineSCI00
  15. #defineSCI11
  17. #defineIDLE_LINE0
  18. #defineADDRESS_MARK1
  20. #defineNORMAL_MODE0
  21. #defineLOOP_MODE1
  22. #defineSING_WIRE_MODE2
  24. #defineRUN_MODE0
  25. #defineWAIT_MODE1
  27. /*FunctionDeclaration*/
  29. /**
  30. *SettheBaudRateoftheSCI.
  31. *@paramport,portcanbeSCI0/SCI1
  32. *@parambaudRate,thewantedbaudrate.
  33. *@parambusClk,TheSCImoduleclock.
  34. */
  35. voidSCISetBaudRate(unsignedcharport,unsignedlongbaudRate,unsignedlongbusClk);
  37. /**
  38. *SettheInterruptEnableBit
  39. *@paramportportcanbeSCI0/SCI1
  40. *@paramtieTransmitterInterruptEnableBIt
  41. *@paramtcieTransmissionCompleteInterruptEnableBIt
  42. *@paramrieReceiverFullInterruptEnableBIt
  43. *@paramilieIdleLineInterruptEnableBIt
  44. *0InterruptrequestsDisabled
  45. *1InterruptrequestsEnabled
  46. */
  47. voidSCISetIEBit(unsignedcharport,unsignedchartie,unsignedchartcie,unsignedcharrie,unsignedcharilie);
  49. /**
  50. *EnableTheTxinterrupt(TransmitterInterruptEnableBIt)
  51. *@paramport,portcanbeSCI0/SCI1
  52. */
  53. voidSCIEnableTxInt(unsignedcharport);
  55. /**
  56. *DisableTheTxinterrupt(TransmitterInterruptEnableBIt)
  57. *@paramport,portcanbeSCI0/SCI1
  58. */
  59. voidSCIDisTxInt(unsignedcharport);
  61. /**
  62. *Enable/DisableSCIReceiver
  63. *@paramportportcanbeSCI0/SCI1
  64. *@paramisEnable0disable1enable
  65. */
  66. voidSCIEnableRecv(unsignedcharport,unsignedcharisEnable);
  68. /**
  69. *Enable/DisableSCITransmitter
  70. *@paramportportcanbeSCI0/SCI1
  71. *@paramisEnable0disable1enable
  72. */
  73. voidSCIEnableTrans(unsignedcharport,unsignedcharisEnable);
  75. /**
  76. *SettheIdleLineType
  77. *@paramportportcanbeSCI0/SCI1
  78. *@paramtype0Idlecharbitcountbeginsafterstartbit
  79. *1Idlecharbitcountbeginsafterstopbit
  80. */
  81. voidSCISetIdleLineType(unsignedcharport,unsignedchartype);
  83. /**
  84. *SettheWakeupCondition.
  85. *@paramportportcanbeSCI0/SCI1
  86. *@paramcondi0forIdlelinewakeup,1foraddressmarkwakeup
  87. */
  88. voidSCISetWakeupCondi(unsignedcharport,unsignedcharcondi);
  90. /**
  91. *Enable/DisableparityfunctionandsettheParitytype
  92. *@paramportportcanbeSCI0/SCI1
  93. *@paramisEnable0fordisableparityfunction,1forenable
  94. *@paramtype0forEvenParity,1forOddParity
  95. */
  96. voidSCISetParity(unsignedcharport,unsignedcharisEnable,unsignedchartype);
  98. /**
  99. *SettheDataFormatModeBit
  100. *@paramportportcanbeSCI0/SCI1
  101. *@parambitsmustbe8or9
  102. */
  103. voidSCISetDataBit(unsignedcharport,unsignedcharbits);
  105. /**
  106. *Settheworkmodeofoperation
  107. *@paramportportcanbeSCI0/SCI1
  108. *@parammodemodecanbeNORMAL_MODE/LOOP_MODE/SING_WIRE_MODE
  109. */
  110. voidSCISetWorkMode(unsignedcharport,unsignedcharmode);
  112. /**
  113. *Enable/DisabletheSCIinwaitmode
  114. *@paramportportcanbeSCI0/SCI1
  115. *@parammodemodecanbeRUN_MODE/WAIT_MODE
  116. */
  117. voidSCISetPowerMode(unsignedcharport,unsignedcharmode);
  119. /**
  120. *SettheTXDIR(OnlyforSingleWireMODE)
  121. *@paramportportcanbeSCI0/SCI1
  122. *@paramdir0TXDusedasinput,1TXDusedasoutput
  123. */
  124. voidSCISetTXDIR(unsignedcharport,unsignedchardir);
  126. /**
  127. *SendacharthrounghSCImodule.
  128. *@paramportportcanbeSCI0/SCI1
  129. *@paramsthedatatobesent
  130. */
  131. voidSCIPutChar(unsignedcharport,unsignedchars);
  133. /**
  134. *ReceiveachardatafromSCImodule,noreply.
  135. *@paramportportcanbeSCI0/SCI1
  136. *@returnthereceivedchar
  137. */
  138. unsignedcharSCIGetChar(unsignedcharport);
  140. /**
  141. *Sendashortintvalue(BigEndian)throunghSCImodule.
  142. *@paramportportcanbeSCI0/SCI1
  143. *@paramithedatatobesent
  144. */
  145. voidSCIPutShortBigEndian(unsignedcharport,shorti);
  147. /**
  148. *Sendashortintvalue(LittleEndian)throunghSCImodule.
  149. *@paramportportcanbeSCI0/SCI1
  150. *@paramithedatatobesent
  151. */
  152. voidSCIPutShortLittleEndian(unsignedcharport,shorti);
  154. /**
  155. *Sendalongintvalue(BigEndian)throunghSCImodule.
  156. *@paramportportcanbeSCI0/SCI1
  157. *@paramithedatatobesent
  158. */
  159. voidSCIPutLongBigEndian(unsignedcharport,longi);
  161. /**
  162. *Sendalongintvalue(LittleEndian)throunghSCImodule.
  163. *@paramportportcanbeSCI0/SCI1
  164. *@paramithedatatobesent
  165. */
  166. voidSCIPutLongLittleEndian(unsignedcharport,longi);
  168. /**
  169. *SendacharstringthrounghSCImodule.
  170. *@paramportportcanbeSCI0/SCI1
  171. *@param*strthestringtobesent
  172. */
  173. voidSCIPutStr(unsignedcharport,unsignedchar*str);
  176. /**
  177. *SenddatathrounghSCImodule.
  178. *@paramportportcanbeSCI0/SCI1
  179. *@param*ppointertothedatatobesent
  180. *@paramsizethesize(byte)ofthedata
  181. */
  182. voidSCIWrite(unsignedcharport,void*p,intsize);
  184. #endif

下面給個(gè)簡單的例子

  1. #include/*commondefinesandmacros*/
  2. #include"derivative.h"/*derivative-specificdefinitions*/
  3. #include"sci.h"
  5. voidmain(void)
  6. {
  7. charC;
  8. EnableInterrupts;
  10. SCISetWorkMode(SCI0,NORMAL_MODE);
  11. SCISetPowerMode(SCI0,RUN_MODE);
  12. SCISetBaudRate(SCI0,9600,16384000L);//16MClock
  13. SCISetDataBit(SCI0,8);
  14. SCISetParity(SCI0,0,0);
  15. SCIEnableRecv(SCI0,1);
  16. SCIEnableTrans(SCI0,1);
  18. for(;;)
  19. {
  20. _FEED_COP();/*feedsthedog*/
  21. C=SCIGetChar(SCI0);
  22. SCIPutChar(SCI0,C);
  23. }/*loopforever*/
  25. /*pleasemakesurethatyouneverleavemain*/
  26. }


先寫這么多，剩下的明天繼續(xù)。下一篇筆記中將給出如何利用串口的收發(fā)中斷和環(huán)形緩沖區(qū)來實(shí)現(xiàn)較為完善的串口驅(qū)動(dòng)。

關(guān)鍵詞： Freescale9S12系列單片

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