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STM32F10x 學習筆記6（USART實現(xiàn)串口通訊 2）

作者： 時間：2016-11-20 來源：網(wǎng)絡 收藏
這次講講利用串口收發(fā)中斷來進行串口通訊。STM32 上為每個串口分配了一個中斷。也就是說無論是發(fā)送完成還是收到數(shù)據(jù)或是數(shù)據(jù)溢出都產(chǎn)生同一個中斷。程序需在中斷處理函數(shù)中讀取狀態(tài)寄存器(USART_SR)來判斷當前的是什么中斷。下面的中斷映像圖給出了這些中斷源是如何匯合成最終的中斷信號的。圖中也給出了如何控制每一個單獨的中斷源是否起作用。

本文引用地址：http://m.butianyuan.cn/article/201611/318841.htm

另外，Cortex-M3內核中還有個NVIC，可以控制這里的中斷信號是否觸發(fā)中斷處理函數(shù)的執(zhí)行，還有這些外部中斷的級別。關于NVIC可以參考《ARMCortexM3權威指南》，里面講解的非常詳細。

簡單的說，為了開啟中斷，我們需要如下的代碼：

  1. NVIC_InitTypeDefNVIC_InitStructure;
  2. NVIC_InitStructure.NVIC_IRQChannel=USART1_IRQn;
  3. NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;
  4. NVIC_InitStructure.NVIC_IRQChannelSubPriority=0;
  5. NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
  6. NVIC_Init(&NVIC_InitStructure);
  8. USART_ITConfig(USART1,USART_IT_RXNE,ENABLE);//開啟接收中斷
  9. USART_ITConfig(USART1,USART_IT_TXE,ENABLE);//開啟發(fā)送中斷

這里多說一句，串口的發(fā)送中斷有兩個，分別是：

  1. l發(fā)送數(shù)據(jù)寄存器空中斷（TXE）
  2. l發(fā)送完成中斷（TC）

一般來說我們會使用發(fā)送數(shù)據(jù)寄存器空中斷，用這個中斷發(fā)送的效率會高一些。

中斷處理函數(shù)的框架如下，如果檢測到錯誤就清除錯誤，收到數(shù)了就處理。發(fā)完當前數(shù)據(jù)了就發(fā)下一個。

  1. voidUSART1_IRQHandler(void)
  2. {
  3. unsignedintdata;
  5. if(USART1->SR&0x0F)
  6. {
  7. //Seeifwehavesomekindoferror,Clearinterrupt
  8. data=USART1->DR;
  9. }
  10. elseif(USART1->SR&USART_FLAG_RXNE)//ReceiveDataRegFullFlag
  11. {
  12. data=USART1->DR;
  13. //對收到的數(shù)據(jù)進行處理，或者干些其他的事
  14. }
  15. elseif(USART1->SR&USART_FLAG_TXE)
  16. {
  17. {//可以發(fā)送數(shù)據(jù)了，如果沒有數(shù)據(jù)需要發(fā)送，就在這里關閉發(fā)送中斷
  18. USART1->DR=something;//Yes,Sendcharacter
  19. }
  20. }
  21. }

下面給一個利用環(huán)形緩沖區(qū)的串口驅動程序。

  1. #ifndef_COM_BUFFERED_H_
  2. #define_COM_BUFFERED_H_
  4. #defineCOM10
  5. #defineCOM21
  7. #defineCOM_RX_BUF_SIZE64/*NumberofcharactersinRxringbuffer*/
  8. #defineCOM_TX_BUF_SIZE64/*NumberofcharactersinTxringbuffer*/
  10. #defineCOM_NO_ERR0/*Functioncallwassuccessful*/
  11. #defineCOM_BAD_CH1/*Invalidcommunicationsportchannel*/
  12. #defineCOM_RX_EMPTY2/*Rxbufferisempty,nocharacteravailable*/
  13. #defineCOM_TX_FULL3/*Txbufferisfull,couldnotdepositcharacter*/
  14. #defineCOM_TX_EMPTY4/*IftheTxbufferisempty.*/
  17. /************************************************************
  18. *function:COMGetCharB
  19. *parameter:charport,portcanbeCOM1/COM2
  20. *parameter:char*errisapointertowhereanerrorcodewillbeplaced:
  21. **errissettoCOM_NO_ERRifacharacterisavailable
  22. **errissettoCOM_RX_EMPTYiftheRxbufferisempty
  23. **errissettoCOM_BAD_CHifyouhavespecifiedaninvalidchannel
  24. *return:char
  25. *usage:Thisfunctioniscalledbyyourapplicationtoobtainacharacterfromthecommunications
  26. *channel.
  27. *changelog:
  28. *************************************************************/
  29. unsignedcharCOMGetCharB(unsignedcharch,unsignedchar*err);
  31. /************************************************************
  32. *function:COMPutCharB
  33. *parameter:charport,portcanbeCOM1/COM2
  34. *return:COMM_NO_ERRifthefunctionwassuccessful(thebufferwasnotfull)
  35. *COMM_TX_FULLifthebufferwasfull
  36. *COMM_BAD_CHifyouhavespecifiedanincorrectchannel
  38. *usage:Thisfunctioniscalledbyyourapplicationtosendacharacteronthecommunications
  39. *channel.ThecharactertosendisfirstinsertedintotheTxbufferandwillbesentby
  40. *theTxISR.Ifthisisthefirstcharacterplacedintothebuffer,theTxISRwillbe
  41. *enabled.IftheTxbufferisfull,thecharacterwillnotbesent(i.e.itwillbelost)
  42. *changelog:
  43. *************************************************************/
  44. unsignedcharCOMPutCharB(unsignedcharport,unsignedcharc);
  46. /************************************************************
  47. *function:COMBufferInit
  48. *parameter:
  49. *return:
  50. *usage:Thisfunctioniscalledbyyourapplicationtoinitializethecommunicationsmodule.You
  51. *mustcallthisfunctionbeforecallinganyotherfunctions.
  52. *changelog:
  53. *************************************************************/
  54. voidCOMBufferInit(void);
  56. /************************************************************
  57. *function:COMBufferIsEmpty
  58. *parameter:charport,portcanbeCOM1/COM2
  59. *return:char
  60. *usage:Thisfunctioniscalledbyyourapplicationtosee
  61. *ifanycharacterisavailablefromthecommunicationschannel.
  62. *Ifatleastonecharacterisavailable,thefunctionreturns
  63. *FALSE(0)otherwise,thefunctionreturnsTRUE(1).
  64. *changelog:
  65. *************************************************************/
  66. unsignedcharCOMBufferIsEmpty(unsignedcharport);
  68. /************************************************************
  69. *function:COMBufferIsFull
  70. *parameter:charport,portcanbeCOM1/COM2
  71. *return:char
  72. *usage:Thisfunctioniscalledbyyourapplicationtoseeifanymorecharacterscanbeplaced
  73. *intheTxbuffer.Inotherwords,thisfunctionchecktoseeiftheTxbufferisfull.
  74. *Ifthebufferisfull,thefunctionreturnsTRUEotherwise,thefunctionreturnsFALSE.
  75. *changelog:
  76. *************************************************************/
  77. unsignedcharCOMBufferIsFull(unsignedcharport);
  79. #endif

  1. /*
  2. *file:com_buffered.c
  3. *author:LiYuan
  4. *platform:STM32F107
  5. *date:2013-5-5
  6. *version:0.0.1
  7. *description:UARTRingBuffer
  8. **/
  10. #include"stm32f10x_usart.h"
  11. #include"com_buffered.h"
  13. #defineOS_ENTER_CRITICAL()__set_PRIMASK(1)
  14. #defineOS_EXIT_CRITICAL()__set_PRIMASK(0)
  16. /**
  17. *EnablesTransmiterinterrupt.
  18. **/
  19. staticvoidCOMEnableTxInt(unsignedcharport)
  20. {
  21. staticUSART_TypeDef*map[2]={USART1,USART2};
  22. USART_ITConfig(map[port],USART_IT_TXE,ENABLE);
  23. }
  24. /*
  25. *********************************************************************************************************
  26. *DATATYPES
  27. *********************************************************************************************************
  28. */
  29. typedefstruct{
  30. shortRingBufRxCtr;/*NumberofcharactersintheRxringbuffer*/
  31. unsignedchar*RingBufRxInPtr;/*Pointertowherenextcharacterwillbeinserted*/
  32. unsignedchar*RingBufRxOutPtr;/*Pointerfromwherenextcharacterwillbeextracted*/
  33. unsignedcharRingBufRx[COM_RX_BUF_SIZE];/*Ringbuffercharacterstorage(Rx)*/
  34. shortRingBufTxCtr;/*NumberofcharactersintheTxringbuffer*/
  35. unsignedchar*RingBufTxInPtr;/*Pointertowherenextcharacterwillbeinserted*/
  36. unsignedchar*RingBufTxOutPtr;/*Pointerfromwherenextcharacterwillbeextracted*/
  37. unsignedcharRingBufTx[COM_TX_BUF_SIZE];/*Ringbuffercharacterstorage(Tx)*/
  38. }COM_RING_BUF;
  40. /*
  41. *********************************************************************************************************
  42. *GLOBALVARIABLES
  43. *********************************************************************************************************
  44. */
  46. COM_RING_BUFCOM1Buf;
  47. COM_RING_BUFCOM2Buf;
  50. /************************************************************
  51. *function:COMGetCharB
  52. *parameter:charport,portcanbeCOM1/COM2
  53. *parameter:char*errisapointertowhereanerrorcodewillbeplaced:
  54. **errissettoCOM_NO_ERRifacharacterisavailable
  55. **errissettoCOM_RX_EMPTYiftheRxbufferisempty
  56. **errissettoCOM_BAD_CHifyouhavespecifiedaninvalidchannel
  57. *return:char
  58. *usage:Thisfunctioniscalledbyyourapplicationtoobtainacharacterfromthecommunications
  59. *channel.
  60. *changelog:
  61. *************************************************************/
  62. unsignedcharCOMGetCharB(unsignedcharport,unsignedchar*err)
  63. {
  64. //unsignedcharcpu_sr;
  66. unsignedcharc;
  67. COM_RING_BUF*pbuf;
  69. switch(port)
  70. {/*Obtainpointertocommunicationschannel*/
  71. caseCOM1:
  72. pbuf=&COM1Buf;
  73. break;
  75. caseCOM2:
  76. pbuf=&COM2Buf;
  77. break;
  79. default:
  80. *err=COM_BAD_CH;
  81. return(0);
  82. }
  83. OS_ENTER_CRITICAL();
  84. if(pbuf->RingBufRxCtr>0)/*Seeifbufferisempty*/
  85. {
  86. pbuf->RingBufRxCtr--;/*No,decrementcharactercount*/
  87. c=*pbuf->RingBufRxOutPtr++;/*Getcharacterfrombuffer*/
  88. if(pbuf->RingBufRxOutPtr==&pbuf->RingBufRx[COM_RX_BUF_SIZE])
  89. {
  90. pbuf->RingBufRxOutPtr=&pbuf->RingBufRx[0];/*WrapOUTpointer*/
  91. }
  92. OS_EXIT_CRITICAL();
  93. *err=COM_NO_ERR;
  94. return(c);
  95. }else{
  96. OS_EXIT_CRITICAL();
  97. *err=COM_RX_EMPTY;
  98. c=0;/*Bufferisempty,return0*/
  99. return(c);
  100. }
  101. }
  104. /************************************************************
  105. *function:COMPutCharB
  106. *parameter:charport,portcanbeCOM1/COM2
  107. *return:COMM_NO_ERRifthefunctionwassuccessful(thebufferwasnotfull)
  108. *COMM_TX_FULLifthebufferwasfull
  109. *COMM_BAD_CHifyouhavespecifiedanincorrectchannel
  111. *usage:Thisfunctioniscalledbyyourapplicationtosendacharacteronthecommunications
  112. *channel.ThecharactertosendisfirstinsertedintotheTxbufferandwillbesentby
  113. *theTxISR.Ifthisisthefirstcharacterplacedintothebuffer,theTxISRwillbe
  114. *enabled.IftheTxbufferisfull,thecharacterwillnotbesent(i.e.itwillbelost)
  115. *changelog:
  116. *1.firstimplimentedbyliyuan2010.11.5
  117. *************************************************************/
  118. unsignedcharCOMPutCharB(unsignedcharport,unsignedcharc)
  119. {
  120. //unsignedcharcpu_sr;
  122. COM_RING_BUF*pbuf;
  123. switch(port)
  124. {/*Obtainpointertocommunicationschannel*/
  125. caseCOM1:
  126. pbuf=&COM1Buf;
  127. break;
  129. caseCOM2:
  130. pbuf=&COM2Buf;
  131. break;
  133. default:
  134. return(COM_BAD_CH);
  135. }
  137. OS_ENTER_CRITICAL();
  138. if(pbuf->RingBufTxCtr
  139. pbuf->RingBufTxCtr++;/*No,incrementcharactercount*/
  140. *pbuf->RingBufTxInPtr++=c;/*Putcharacterintobuffer*/
  141. if(pbuf->RingBufTxInPtr==&pbuf->RingBufTx[COM_TX_BUF_SIZE]){/*WrapINpointer*/
  142. pbuf->RingBufTxInPtr=&pbuf->RingBufTx[0];
  143. }
  144. if(pbuf->RingBufTxCtr==1){/*Seeifthisisthefirstcharacter*/
  145. COMEnableTxInt(port);/*Yes,EnableTxinterrupts*/
  146. OS_EXIT_CRITICAL();
  147. }else{
  148. OS_EXIT_CRITICAL();
  149. }
  150. return(COM_NO_ERR);
  151. }else{
  152. OS_EXIT_CRITICAL();
  153. return(COM_TX_FULL);
  154. }
  155. }
  157. /************************************************************
  158. *function:COMBufferInit
  159. *parameter:
  160. *return:
  161. *usage:Thisfunctioniscalledbyyourapplicationtoinitializethecommunicationsmodule.You
  162. *mustcallthisfunctionbeforecallinganyotherfunctions.
  163. *changelog:
  164. *************************************************************/
  165. voidCOMBufferInit(void)
  166. {
  167. COM_RING_BUF*pbuf;
  169. pbuf=&COM1Buf;/*InitializetheringbufferforCOM0*/
  170. pbuf->RingBufRxCtr=0;
  171. pbuf->RingBufRxInPtr=&pbuf->RingBufRx[0];
  172. pbuf->RingBufRxOutPtr=&pbuf->RingBufRx[0];
  173. pbuf->RingBufTxCtr=0;
  174. pbuf->RingBufTxInPtr=&pbuf->RingBufTx[0];
  175. pbuf->RingBufTxOutPtr=&pbuf->RingBufTx[0];
  177. pbuf=&COM2Buf;/*InitializetheringbufferforCOM1*/
  178. pbuf->RingBufRxCtr=0;
  179. pbuf->RingBufRxInPtr=&pbuf->RingBufRx[0];
  180. pbuf->RingBufRxOutPtr=&pbuf->RingBufRx[0];
  181. pbuf->RingBufTxCtr=0;
  182. pbuf->RingBufTxInPtr=&pbuf->RingBufTx[0];
  183. pbuf->RingBufTxOutPtr=&pbuf->RingBufTx[0];
  184. }
  186. /************************************************************
  187. *function:COMBufferIsEmpty
  188. *parameter:charport,portcanbeCOM1/COM2
  189. *return:char
  190. *usage:Thisfunctioniscalledbyyourapplicationtosee
  191. *ifanycharacterisavailablefromthecommunicationschannel.
  192. *Ifatleastonecharacterisavailable,thefunctionreturns
  193. *FALSE(0)otherwise,thefunctionreturnsTRUE(1).
  194. *changelog:
  195. *************************************************************/
  196. unsignedcharCOMBufferIsEmpty(unsignedcharport)
  197. {
  198. //unsignedcharcpu_sr;
  200. unsignedcharempty;
  201. COM_RING_BUF*pbuf;
  202. switch(port)
  203. {/*Obtainpointertocommunicationschannel*/
  204. caseCOM1:
  205. pbuf=&COM1Buf;
  206. break;
  208. caseCOM2:
  209. pbuf=&COM2Buf;
  210. break;
  212. default:
  213. return(1);
  214. }
  215. OS_ENTER_CRITICAL();
  216. if(pbuf->RingBufRxCtr>0)
  217. {/*Seeifbufferisempty*/
  218. empty=0;/*BufferisNOTempty*/
  219. }
  220. else
  221. {
  222. empty=1;/*Bufferisempty*/
  223. }
  224. OS_EXIT_CRITICAL();
  225. return(empty);
  226. }
  229. /************************************************************
  230. *function:COMBufferIsFull
  231. *parameter:charport,portcanbeCOM1/COM2
  232. *return:char
  233. *usage:Thisfunctioniscalledbyyourapplicationtoseeifanymorecharacterscanbeplaced
  234. *intheTxbuffer.Inotherwords,thisfunctionchecktoseeiftheTxbufferisfull.
  235. *Ifthebufferisfull,thefunctionreturnsTRUEotherwise,thefunctionreturnsFALSE.
  236. *changelog:
  237. *************************************************************/
  238. unsignedcharCOMBufferIsFull(unsignedcharport)
  239. {
  240. //unsignedcharcpu_sr;
  242. charfull;
  243. COM_RING_BUF*pbuf;
  244. switch(port)
  245. {/*Obtainpointertocommunicationschannel*/
  246. caseCOM1:
  247. pbuf=&COM1Buf;
  248. break;
  250. caseCOM2:
  251. pbuf=&COM2Buf;
  252. break;
  254. default:
  255. return(1);
  256. }
  257. OS_ENTER_CRITICAL();
  258. if(pbuf->RingBufTxCtr
  259. full=0;/*BufferisNOTfull*/
  260. }else{
  261. full=1;/*Bufferisfull*/
  262. }
  263. OS_EXIT_CRITICAL();
  264. return(full);
  265. }
  268. //ThisfunctioniscalledbytheRxISRtoinsertacharacterintothereceiveringbuffer.
  269. staticvoidCOMPutRxChar(unsignedcharport,unsignedcharc)
  270. {
  271. COM_RING_BUF*pbuf;
  273. switch(port)
  274. {/*Obtainpointertocommunicationschannel*/
  275. caseCOM1:
  276. pbuf=&COM1Buf;
  277. break;
  279. caseCOM2:
  280. pbuf=&COM2Buf;
  281. break;
  283. default:
  284. return;
  285. }
  286. if(pbuf->RingBufRxCtr
  287. pbuf->RingBufRxCtr++;/*No,incrementcharactercount*/
  288. *pbuf->RingBufRxInPtr++=c;/*Putcharacterintobuffer*/
  289. if(pbuf->RingBufRxInPtr==&pbuf->RingBufRx[COM_RX_BUF_SIZE]){/*WrapINpointer*/
  290. pbuf->RingBufRxInPtr=&pbuf->RingBufRx[0];
  291. }
  292. }
  293. }
  296. //ThisfunctioniscalledbytheTxISRtoextractthenextcharacterfromtheTxbuffer.
  297. //ThefunctionreturnsFALSEifthebufferisemptyafterthecharacterisextractedfrom
  298. //thebuffer.ThisisdonetosignaltheTxISRtodisableinterruptsbecausethisisthe
  299. //lastcharactertosend.
  300. staticunsignedcharCOMGetTxChar(unsignedcharport,unsignedchar*err)
  301. {
  302. unsignedcharc;
  303. COM_RING_BUF*pbuf;
  305. switch(port)
  306. {/*Obtainpointertocommunicationschannel*/
  307. caseCOM1:
  308. pbuf=&COM1Buf;
  309. break;
  311. caseCOM2:
  312. pbuf=&COM2Buf;
  313. break;
  315. default:
  316. *err=COM_BAD_CH;
  317. return(0);
  318. }
  319. if(pbuf->RingBufTxCtr>0){/*Seeifbufferisempty*/
  320. pbuf->RingBufTxCtr--;/*No,decrementcharactercount*/
  321. c=*pbuf->RingBufTxOutPtr++;/*Getcharacterfrombuffer*/
  322. if(pbuf->RingBufTxOutPtr==&pbuf->RingBufTx[COM_TX_BUF_SIZE])
  323. {
  324. pbuf->RingBufTxOutPtr=&pbuf->RingBufTx[0];/*WrapOUTpointer*/
  325. }
  326. *err=COM_NO_ERR;
  327. return(c);/*Charactersarestillavailable*/
  328. }else{
  329. *err=COM_TX_EMPTY;
  330. return(0);/*Bufferisempty*/
  331. }
  332. }
  335. voidUSART1_IRQHandler(void)
  336. {
  337. unsignedintdata;
  338. unsignedcharerr;
  340. if(USART1->SR&0x0F)
  341. {
  342. //Seeifwehavesomekindoferror
  343. //Clearinterrupt(donothingaboutit!)
  344. data=USART1->DR;
  345. }
  346. elseif(USART1->SR&USART_FLAG_RXNE)//ReceiveDataRegFullFlag
  347. {
  348. data=USART1->DR;
  349. COMPutRxChar(COM1,data);//Insertreceivedcharacterintobuffer
  350. }
  351. elseif(USART1->SR&USART_FLAG_TXE)
  352. {
  353. data=COMGetTxChar(COM1,&err);//Getnextcharactertosend.
  354. if(err==COM_TX_EMPTY)
  355. {//Dowehaveanymorecharacterstosend?
  356. //No,DisableTxinterrupts
  357. //USART_ITConfig(USART1,USART_IT_TXE|USART_IT_TC,ENABLE);
  358. USART1->CR1&=~USART_FLAG_TXE|USART_FLAG_TC;
  359. }
  360. else
  361. {
  362. USART1->DR=data;//Yes,Sendcharacter
  363. }
  364. }
  365. }
  367. voidUSART2_IRQHandler(void)
  368. {
  369. unsignedintdata;
  370. unsignedcharerr;
  372. if(USART2->SR&0x0F)
  373. {
  374. //Seeifwehavesomekindoferror
  375. //Clearinterrupt(donothingaboutit!)
  376. data=USART2->DR;
  377. }
  378. elseif(USART2->SR&USART_FLAG_RXNE)//ReceiveDataRegFullFlag
  379. {
  380. data=USART2->DR;
  381. COMPutRxChar(COM2,data);//Insertreceivedcharacterintobuffer
  382. }
  383. elseif(USART2->SR&USART_FLAG_TXE)
  384. {
  385. data=COMGetTxChar(COM2,&err);//Getnextcharactertosend.
  386. if(err==COM_TX_EMPTY)
  387. {//Dowehaveanymorecharacterstosend?
  388. //No,DisableTxinterrupts
  389. //USART_ITConfig(USART2,USART_IT_TXE|USART_IT_TC,ENABLE);
  390. USART2->CR1&=~USART_FLAG_TXE|USART_FLAG_TC;
  391. }
  392. else
  393. {
  394. USART2->DR=data;//Yes,Sendcharacter
  395. }
  396. }
  397. }

下面給個例子主程序，來演示如何使用上面的串口驅動代碼。

  1. #include"misc.h"
  2. #include"stm32f10x.h"
  3. #include"com_buffered.h"
  5. voidUART_PutStrB(unsignedcharport,uint8_t*str)
  6. {
  7. while(0!=*str)
  8. {
  9. COMPutCharB(port,*str);
  10. str++;
  11. }
  12. }
  14. voidUSART1_Init(void)
  15. {
  16. GPIO_InitTypeDefGPIO_InitStructure;
  17. USART_InitTypeDefUSART_InitStructure;
  18. NVIC_InitTypeDefNVIC_InitStructure;
  20. RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA|RCC_APB2Periph_USART1,ENABLE);
  22. /*ConfigureUSARTTxasalternatefunctionpush-pull*/
  23. GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;
  24. GPIO_InitStructure.GPIO_Pin=GPIO_Pin_9;
  25. GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
  26. GPIO_Init(GPIOA,&GPIO_InitStructure);
  28. /*ConfigureUSARTRxasinputfloating*/
  29. GPIO_InitStructure.GPIO_Mode=GPIO_Mode_IN_FLOATING;
  30. GPIO_InitStructure.GPIO_Pin=GPIO_Pin_10;
  31. GPIO_Init(GPIOA,&GPIO_InitStructure);
  33. USART_InitStructure.USART_BaudRate=9600;
  34. USART_InitStructure.USART_WordLength=USART_WordLength_8b;
  35. USART_InitStructure.USART_StopBits=USART_StopBits_1;
  36. USART_InitStructure.USART_Parity=USART_Parity_No;
  37. USART_InitStructure.USART_HardwareFlowControl=USART_HardwareFlowControl_None;
  38. USART_InitStructure.USART_Mode=USART_Mode_Rx|USART_Mode_Tx;
  39. USART_Init(USART1,&USART_InitStructure);
  41. USART_Cmd(USART1,ENABLE);
  43. NVIC_InitStructure.NVIC_IRQChannel=USART1_IRQn;
  44. NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=0;
  45. NVIC_InitStructure.NVIC_IRQChannelSubPriority=0;
  46. NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
  47. NVIC_Init(&NVIC_InitStructure);
  48. }
  50. voidUSART2_Init(void)
  51. {
  52. GPIO_InitTypeDefGPIO_InitStructure;
  53. USART_InitTypeDefUSART_InitStructure;
  54. NVIC_InitTypeDefNVIC_InitStructure;
  56. RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOD|RCC_APB2Periph_AFIO,ENABLE);
  58. /*ConfigureUSARTTxasalternatefunctionpush-pull*/
  59. GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF_PP;
  60. GPIO_InitStructure.GPIO_Pin=GPIO_Pin_5;
  61. GPIO_InitStructure.GPIO_Speed=GPIO_Speed_50MHz;
  62. GPIO_Init(GPIOD,&GPIO_InitStructure);
  64. /*ConfigureUSARTRxasinputfloating*/
  65. GPIO_InitStructure.GPIO_Mode=GPIO_Mode_IN_FLOATING;
  66. GPIO_InitStructure.GPIO_Pin=GPIO_Pin_6;
  67. GPIO_Init(GPIOD,&GPIO_InitStructure);
  69. GPIO_PinRemapConfig(GPIO_Remap_USART2,ENABLE);
  70. RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART2,ENABLE);
  72. USART_InitStructure.USART_BaudRate=9600;
  73. USART_InitStructure.USART_WordLength=USART_WordLength_8b;
  74. USART_InitStructure.USART_StopBits=USART_StopBits_1;
  75. USART_InitStructure.USART_Parity=USART_Parity_No;
  76. USART_InitStructure.USART_HardwareFlowControl=USART_HardwareFlowControl_None;
  77. USART_InitStructure.USART_Mode=USART_Mode_Rx|USART_Mode_Tx;
  78. USART_Init(USART2,&USART_InitStructure);
  80. USART_Cmd(USART2,ENABLE);
  82. NVIC_InitStructure.NVIC_IRQChannel=USART2_IRQn;
  83. NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority=1;
  84. NVIC_InitStructure.NVIC_IRQChannelSubPriority=1;
  85. NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE;
  86. NVIC_Init(&NVIC_InitStructure);
  87. }
  90. intmain(void)
  91. {
  92. unsignedcharc;
  93. unsignedcharerr;
  95. USART1_Init();
  96. USART2_Init();
  97. COMBufferInit();
  98. USART_ITConfig(USART1,USART_IT_RXNE,ENABLE);
  99. USART_ITConfig(USART2,USART_IT_RXNE,ENABLE);
  101. UART_PutStrB(COM1,"HelloWorld!n");
  102. for(;;)
  103. {
  104. c=COMGetCharB(COM1,&err);
  105. if(err==COM_NO_ERR)
  106. {
  107. COMPutCharB(COM1,c);
  108. }
  109. }
  110. }

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