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Freescale 9S12 系列单片机应用笔记（SCI）1

作者： 时间：2016-11-20 来源：网络
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SCI模块应用笔记（1）

UART，也就是异步串行通讯接口是单片机中最常见的外设，几乎每种类型的单片机都必备1到2个UART接口，9S12系列单片机也不例外。不过，摩托罗拉给他自己的单片机的串口起了个很有个性的缩写名称SCI（serialcommunicationinterface），其实就是我们常说的UART。

本文引用地址：https://www.eepw.com.cn/article/201611/318823.htm

各种单片机串口的编程都大同小异，无非就是设置波特率、起始位、停止位、校验位等等。下面通过给出编程例子的方式分别介绍。

设置波特率

  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. }

设置奇偶校验位

  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. }


使能数据位的长度

  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. }


设置串口的工作模式

NORMAL_MODE是我们通常用的模式

LOOP_MODE是自发自收模式

SING_WIRE_MODE就是收发公用一条数据线的模式

  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. }

设置SCI模块是否在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模块的接收功能

  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模块的发送功能

  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. }

发送数据

  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是发送完成
  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. }


接收数据

  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. }

相应的头文件

  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

下面给个简单的例子

  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. }


先写这么多，剩下的明天继续。下一篇笔记中将给出如何利用串口的收发中断和环形缓冲区来实现较为完善的串口驱动。

关键词： Freescale9S12系列单片

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