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        Freescale 9S12 系列單片機應用筆記（SCI）1
        
						
        
				作者：
				時間：2016-11-20
				來源：網絡
				
				
				
				
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        SCI模塊應用筆記（1）
        UART，也就是異步串行通訊接口是單片機中最常見的外設，幾乎每種類型的單片機都必備1到2個UART接口，9S12系列單片機也不例外。不過，摩托羅拉給他自己的單片機的串口起了個很有個性的縮寫名稱SCI（serialcommunicationinterface），其實就是我們常說的UART。
        本文引用地址：http://www.104case.com/article/201611/318823.htm
        各種單片機串口的編程都大同小異，無非就是設置波特率、起始位、停止位、校驗位等等。下面通過給出編程例子的方式分別介紹。
        設置波特率
        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. }
        設置奇偶校驗位
        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. }

        使能數據位的長度
        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. }

        設置串口的工作模式
        NORMAL_MODE是我們通常用的模式
        LOOP_MODE是自發自收模式
        SING_WIRE_MODE就是收發公用一條數據線的模式
        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. }
        發送數據
        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. }

        接收數據
        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。下一篇筆記中將給出如何利用串口的收發中斷和環形緩沖區來實現較為完善的串口驅動。
        
				
            
                
			
							
        
                
			              
              
            
        
		
        
		
        
		
        
		
        
		
        
			
          
				
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