1. // 添加这个函数
   
2. int fputc(int ch,FILE *f)
   
3. {
   2 b* O8 r! Z* k( b% R' }* d
4.     uint8_t temp[1]={ch};
   
5.     HAL_UART_Transmit(&UartHandle,temp,1,2);
   
6. }

复制代码

MDK设置：勾选Use Micro LIB

0 T. T2 o; B" k8 H

测试板子：STM32F746NG-DISCOVERY

main.c文件

1. /* Includes ------------------------------------------------------------------*/
   
2. #include "main.h"
   
3. #include <stdio.h>
   3 R7 x/ E2 j2 S" H7 `5 V, B
4. /** @addtogroup STM32F7xx_HAL_Examples
   . y0 U$ A, Q1 K, z" y% x; X4 v- G
5.   * @{
   0 h' Y, d( J2 y+ d
6.   */
   
7. 
   9 R- G: h* Z0 m# v4 Y. J) j
8. /** @addtogroup UART_TwoBoards_ComDMA
   
9.   * @{
   4 Z# h, k0 L6 P
10.   */
    ; |: _- S+ R' l3 Q9 {
11. 
    0 ^6 b9 K% r% ?& T& u, e! q
12. /* Private typedef -----------------------------------------------------------*/
    
13. /* Private define ------------------------------------------------------------*/
    
14. #define TRANSMITTER_BOARD
    # l9 y5 _3 f# I6 ~. ^
15. 
    ( e8 }  N* p) o+ z
16. /* Private macro -------------------------------------------------------------*/
    
17. /* Private variables ---------------------------------------------------------*/
    ' G1 Q3 v8 v$ v. y; r! `
18. /* UART handler declaration */
    ( i2 f2 b5 A% [; q' ?* }
19. UART_HandleTypeDef UartHandle;
    
20. __IO ITStatus UartReady = RESET;
    ) i3 x% Y3 s, o0 C" s. F
21. __IO uint32_t UserButtonStatus = 0;  /* set to 1 after User Button interrupt  */
    9 u" @( Y9 B, \% r3 t% S2 P* T
22. 
    3 R- L! _5 b8 ^( ?$ W
23. /* Buffer used for transmission */
    
24. uint8_t aTxBuffer[] = " ****UART_TwoBoards communication based on DMA****  ****UART_TwoBoards communication based on DMA****  ****UART_TwoBoards communication based on DMA**** ";
    
25. 
    0 R. c( |% z" V. j+ \* Y- W0 r. K
26. /* Buffer used for reception */
    0 b# [& I! y# P$ B! v
27. uint8_t aRxBuffer[RXBUFFERSIZE];
    * f% G5 `' `" X- K9 E& U" S; r
28. 
    
29. /* Private function prototypes -----------------------------------------------*/
    2 B$ [8 o  S# v4 b: _7 q% L# g
30. void SystemClock_Config(void);
    
31. static void Error_Handler(void);
    ' p# X+ m" U" Q
32. static uint16_t Buffercmp(uint8_t* pBuffer1, uint8_t* pBuffer2, uint16_t BufferLength);
    ( i0 a3 q9 N1 @; W7 }
33. static void MPU_Config(void);
    # ]4 L$ }3 q. z- _! r
34. static void CPU_CACHE_Enable(void);
      H0 R% l, _0 o8 T3 P5 i# |
35. 
    ; _( K3 ~  e" J2 o' t
36. /* Private functions ---------------------------------------------------------*/
      b( H/ {3 Z0 c
37. UART_HandleTypeDef UartHandle;
    $ s5 x% q$ S1 v, a8 F
38. uint8_t sendbuf[]="send ok ";
    + Z. m4 u3 Z* i( B  T5 q
39. 
    * E" D+ I3 a! ?* W5 u
40. // 添加这个函数
    
41. int fputc(int ch,FILE *f)
    
42. {
    
43.     uint8_t temp[1]={ch};
    
44.     HAL_UART_Transmit(&UartHandle,temp,1,2);
    1 V$ M' y: T0 q' q% y2 G: ?' o8 c
45. }
    0 {: I. z. d- k* t( d: D1 |
46. 
    ; _4 t6 g8 z  J; b! o$ ^6 j
47. /**
    
48.   * @brief  Main program
    
49.   * @param  None
    6 F" A4 l6 p( n" `! |5 @* ~9 K
50.   * @retval None
    & @' O$ X( c: f. n8 i
51.   */
    ' ]) J& r! o* L4 V' [! i
52. int main(void)
    
53. {
    , \; {+ z5 Q4 ]3 L* [6 Q
54.   /* Configure the MPU attributes as Write Through */
    5 d6 _0 F: F/ G* \5 I# N7 V) Y
55.   MPU_Config();
    6 d' N  M; y3 f  L  e
56. 
    : S- [, |) c2 \% [" Q) P5 W8 C, m
57.   /* Enable the CPU Cache */
    4 @! W( Q  J$ G0 Y8 s' ^
58.   CPU_CACHE_Enable();
    2 I8 o( O0 i0 K$ P' o5 m% I. l+ z( Q( g7 p
59.   /* STM32F7xx HAL library initialization:
    
60.        - Configure the Flash ART accelerator
    
61.        - Systick timer is configured by default as source of time base, but user
    7 ]+ ?9 X4 l* S: W
62.          can eventually implement his proper time base source (a general purpose
    : w% e$ L) P) p# U/ {
63.          timer for example or other time source), keeping in mind that Time base
    
64.          duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and
    + K8 H4 j+ O8 g; v$ j& |
65.          handled in milliseconds basis.
    
66.        - Set NVIC Group Priority to 4
    
67.        - Low Level Initialization
    ) w/ T1 Y+ O" M2 w  `
68.      */
    " L; k3 z4 @& j5 y
69.   HAL_Init();
    4 K3 O6 p8 C, s2 G
70. 
    
71.   /* Configure the system clock to 216 MHz */
    0 J& q; ^8 f3 I' f
72.   SystemClock_Config();
    ' M, `5 \; X, P1 v
73.   
    
74.   /* Configure LED1 */
    
75.   BSP_LED_Init(LED1);
    
76.    
    
77.   UartHandle.Instance        = DISCOVERY_COM1;
    
78. 
    
79.   UartHandle.Init.BaudRate   = 9600;
    
80.   UartHandle.Init.WordLength = UART_WORDLENGTH_8B;
    ; G. t( A; x5 d5 f2 S. c  ]1 h( Y
81.   UartHandle.Init.StopBits   = UART_STOPBITS_1;
    
82.   UartHandle.Init.Parity     = UART_PARITY_NONE;
    $ d5 Z( B! A; r" M0 |4 p
83.   UartHandle.Init.HwFlowCtl  = UART_HWCONTROL_NONE;
    
84.   UartHandle.Init.Mode       = UART_MODE_TX_RX;
    
85.     BSP_COM_DeInit(COM1,&UartHandle);
    * C4 r! W9 g. `
86.     BSP_COM_Init(COM1,&UartHandle);
    
87.    
    
88. //    HAL_UART_Transmit(&UartHandle,sendbuf,sizeof(sendbuf),10);
    
89.   /* Configure User push-button in Interrupt mode */
    
90.   BSP_PB_Init(BUTTON_KEY, BUTTON_MODE_EXTI);
    
91.   
    
92.   /* Wait for User push-button press before starting the Communication.
    
93.      In the meantime, LED1 is blinking */
    ) `7 `4 ^& k" f4 d, r# k4 N
94.     printf("hello");
    
95.    
    * y9 {& T- u' d* }$ T( H9 n: Z, n
96.    
    
97.   while(UserButtonStatus == 0)
    * k& q+ v' F( [
98.   {
    4 \- {9 N( v/ [% k- R- g
99.       /* Toggle LED1*/
    7 w0 ~  m1 F9 o0 u/ v4 S
100.       BSP_LED_Toggle(LED1);
     
101.       HAL_Delay(100);
     
102.   }
     6 @- v2 q3 r; h& o+ y  |
103.   /* Turn on LED1 if test passes then enter infinite loop */
     7 Q# d; V% E  ]9 R: y( P  Z
104.   BSP_LED_On(LED1);
     - ~2 G' W% d5 d( e1 v* t+ m
105.   /* Infinite loop */
     
106.   while (1)
     
107.   {
     
108.   }
     + J4 t# v- L! X
109. }
     3 F9 c- B- {, Z9 ?, ^
110. 
     
111. /**
     
112.   * @brief  System Clock Configuration
     7 b6 A0 q) m- ]+ G0 J, M. ]
113.   *         The system Clock is configured as follow :
     4 W- b, ~/ P. U5 B0 w" `6 s
114.   *            System Clock source            = PLL (HSE)
     
115.   *            SYSCLK(Hz)                     = 216000000
     
116.   *            HCLK(Hz)                       = 216000000
     " f1 a1 y  o6 C  g/ A7 \; w  c4 a3 Y
117.   *            AHB Prescaler                  = 1
     
118.   *            APB1 Prescaler                 = 4
     
119.   *            APB2 Prescaler                 = 2
     - E3 a( G+ J3 ]9 O
120.   *            HSE Frequency(Hz)              = 25000000
     
121.   *            PLL_M                          = 25
     % I: @! k) R* A4 |: L1 g4 Z' Y5 ~2 J
122.   *            PLL_N                          = 432
     & E$ b. i0 r. E- b
123.   *            PLL_P                          = 2
     
124.   *            PLL_Q                          = 9
     + j  @' P, A0 X
125.   *            VDD(V)                         = 3.3
     ( I, g$ b9 T9 O9 V" g
126.   *            Main regulator output voltage  = Scale1 mode
     
127.   *            Flash Latency(WS)              = 7
       E0 Q7 t% j7 S) v* P$ f6 I6 l& J
128.   * @param  None
     
129.   * @retval None
     & [. M; U! U; o8 {
130.   */
     
131. void SystemClock_Config(void)
     , g. E8 Y) @* w! e. Z' k$ \* v
132. {
     3 S8 X3 b4 [7 i. ?8 `& _$ E
133.   RCC_ClkInitTypeDef RCC_ClkInitStruct;
     
134.   RCC_OscInitTypeDef RCC_OscInitStruct;
       t. |2 [  w( Y: K2 x' V+ ^& Q
135.   HAL_StatusTypeDef ret = HAL_OK;
     / F) ~5 Q7 e- ]& t
136. 
     
137.   /* Enable HSE Oscillator and activate PLL with HSE as source */
     0 v  y* X( H" O  r$ ]( v/ T
138.   RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_HSE;
     5 Q; x2 E! S! T
139.   RCC_OscInitStruct.HSEState = RCC_HSE_ON;
     . P6 K7 w$ i, f2 X! o: Y
140.   RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
     $ O& p% j' U: I1 x: o
141.   RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_HSE;
     ( B6 S) {( ^1 T; y( z$ B
142.   RCC_OscInitStruct.PLL.PLLM = 25;
     
143.   RCC_OscInitStruct.PLL.PLLN = 432;
     " \& i  F% {' c; N
144.   RCC_OscInitStruct.PLL.PLLP = RCC_PLLP_DIV2;
     2 Y. y/ ?, R/ k) @; b# L
145.   RCC_OscInitStruct.PLL.PLLQ = 9;
     ; Q" K9 k, p1 `; C& E% D4 R$ p4 ?
146.   
     
147.   ret = HAL_RCC_OscConfig(&RCC_OscInitStruct);
       S% x0 y3 U4 ]' |$ m
148.   if(ret != HAL_OK)
     * y  K+ R+ q- \3 e$ |* l! K
149.   {
     
150.     while(1) { ; }
     
151.   }
     
152.   
     
153.   /* Activate the OverDrive to reach the 216 MHz Frequency */  
     6 H* I2 ?2 I2 l: Q% ]& Q; ^
154.   ret = HAL_PWREx_EnableOverDrive();
     
155.   if(ret != HAL_OK)
     3 ^; i# r) d% W* d( j
156.   {
     
157.     while(1) { ; }
     
158.   }
     
159.   
     : f, n& n& L$ O& G% D2 C
160.   /* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2 clocks dividers */
     : S( ^6 b- d, L; B1 T
161.   RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
     2 ~! P4 f  L* x, q
162.   RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
     
163.   RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
     
164.   RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV4;  
     
165.   RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV2;
     
166.   
     , S! o; [, [! ~" w
167.   ret = HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_7);
     0 _9 n1 e( \- [. R! P8 F$ }
168.   if(ret != HAL_OK)
     
169.   {
     
170.     while(1) { ; }
     / u, z; [4 i- \
171.   }  
       |/ e+ ?- f& ]+ \" [# P7 n4 @
172. }
     . G4 @" m+ _, ?' y3 m# m
173. 
     2 F! L" c& Y; N3 ^7 e" K
174. /**
     0 [& z- I8 }5 ?- k
175.   * @brief  Tx Transfer completed callback
     * c: l& g9 ]+ r' `: U* ?
176.   * @param  UartHandle: UART handle.
     + s! W: |' v* u3 L" [+ a
177.   * @note   This example shows a simple way to report end of DMA Tx transfer, and
     
178.   *         you can add your own implementation.
     ! s- Z: J: C! U6 d- e% t9 d
179.   * @retval None
     : p6 s4 r* q1 |7 O6 W* y
180.   */
     
181. void HAL_UART_TxCpltCallback(UART_HandleTypeDef *UartHandle)
     
182. {
     , ^$ I5 Z$ _$ J4 G
183.   /* Set transmission flag: trasfer complete*/
     
184.   UartReady = SET;
     
185. 
     
186.   
     
187. }
     1 P! T7 |& n" E8 s
188. 
     - B+ a0 K+ w+ T" c* @$ {
189. /**
     ( _, C: }+ Q$ u6 n1 n) c- K
190.   * @brief  Rx Transfer completed callback
     
191.   * @param  UartHandle: UART handle
     
192.   * @note   This example shows a simple way to report end of DMA Rx transfer, and
     $ B" B4 d1 c" c  |
193.   *         you can add your own implementation.
     
194.   * @retval None
     ; b- v9 Z$ Y! ]7 z4 D) z
195.   */
     
196. void HAL_UART_RxCpltCallback(UART_HandleTypeDef *UartHandle)
     
197. {
     - @7 F/ F: \& u- {; _
198.   /* Set transmission flag: trasfer complete*/
     
199.   UartReady = SET;
     ! ]* {. \& U1 r6 {) ?8 z$ S
200. 
     2 K* V& g. P+ k8 O
201.   
     
202. }
     6 S$ v. n) `( s# D+ @+ R
203. 
     + L9 B+ T; G6 z9 T$ S6 X
204. /**
     3 Z) g3 b4 b: [, i9 z# I
205.   * @brief  UART error callbacks
     
206.   * @param  UartHandle: UART handle
     
207.   * @note   This example shows a simple way to report transfer error, and you can
     4 ~. x6 T$ ~( L# A7 l4 L
208.   *         add your own implementation.
     / D7 g3 G3 t& U% w) Z. i
209.   * @retval None
     ! I) V6 w! G) n  n
210.   */
     
211. void HAL_UART_ErrorCallback(UART_HandleTypeDef *UartHandle)
     
212. {
     
213.     Error_Handler();
     
214. }
     / g9 m0 B2 Y1 v* n- a- T# c3 Z- N* c
215. 
     / @% Q- [8 x9 f8 y$ G
216. 
     
217. /**
     
218.   * @brief EXTI line detection callbacks
     % N- F* ]4 \; T5 r- V5 X
219.   * @param GPIO_Pin: Specifies the pins connected EXTI line
     
220.   * @retval None
     * t! E; J2 U# {# T. W' l
221.   */
     
222. void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
     6 m! i0 B% K( l1 K2 a: [
223. {
     2 a7 k/ C: q' @- z8 r
224.   if(GPIO_Pin == KEY_BUTTON_PIN)
     6 D0 l& f9 ?/ r& l7 O9 x8 _" i5 K
225.   {  
     6 w" W9 N) ^; X! u$ a* ^
226.     UserButtonStatus = 1;
     ; P. [6 @1 `' D& Z4 \5 X( K
227.   }
     4 z/ r2 Y9 T# Z) |, G7 t
228. }
     ; Z8 {  ]5 T3 x8 Q/ E1 W2 q
229. 
     
230. /**
     
231.   * @brief  Compares two buffers.
     
232.   * @param  pBuffer1, pBuffer2: buffers to be compared.
     0 Y* w; }2 \' H4 U5 L
233.   * @param  BufferLength: buffer's length
     
234.   * @retval 0  : pBuffer1 identical to pBuffer2
     
235.   *         >0 : pBuffer1 differs from pBuffer2
     4 R0 O& D9 W* S* t# d7 f9 h! P8 t
236.   */
     
237. static uint16_t Buffercmp(uint8_t* pBuffer1, uint8_t* pBuffer2, uint16_t BufferLength)
     / s0 `/ H& n( u) N4 {4 _3 g. G
238. {
     5 ]5 {( B# G, ~+ }( W
239.   while (BufferLength--)
     
240.   {
     4 t# K4 x4 \2 I% u9 Q
241.     if ((*pBuffer1) != *pBuffer2)
     
242.     {
     - I* i  D( @& `2 ]7 W' N
243.       return BufferLength;
     4 m8 C1 \  K# e2 B6 D9 ]1 Y$ m
244.     }
     
245.     pBuffer1++;
     3 X5 d( @! l& c( g9 ^" A
246.     pBuffer2++;
     ' F! Y3 a% u6 L4 {, @4 N
247.   }
     8 Q% S) `' ]! z
248. 
     2 p$ T  C1 x/ G! Y+ d3 G6 ]$ {3 [8 t2 z
249.   return 0;
     
250. }
     9 P) ~  z4 W; G
251. 
     : D- f1 r5 W6 r0 W( }1 p
252. /**
     
253.   * @brief  This function is executed in case of error occurrence.
     8 N) L4 {4 U2 h: S1 _4 g+ ~+ I# a
254.   * @param  None
     6 ^# D" ~3 ^5 ]6 q1 Y
255.   * @retval None
     
256.   */
     
257. static void Error_Handler(void)
     
258. {
     3 a; A8 f3 c8 Z' f, F" Q
259.   /* Turn LED1 on */
     ! U0 s6 N, M% k0 I9 C2 g
260.   BSP_LED_On(LED1);
     : R8 n- w! B* e. _; J/ T
261.   while(1)
     
262.   {
     8 D& R" s$ @+ J! h; ]2 u1 P
263.     /* Error if LED1 is slowly blinking (1 sec. period) */
     
264.     BSP_LED_Toggle(LED1);
     9 `7 r9 h1 i, y& f4 h
265.     HAL_Delay(1000);
     6 H1 K9 K  z$ ]7 j6 @7 V# U! @* j
266.   }  
     
267. }
     
268. 
     2 k4 j" C2 a( w# Y# S' z
269. #ifdef  USE_FULL_ASSERT
     
270. 
     
271. /**
     
272.   * @brief  Reports the name of the source file and the source line number
     
273.   *         where the assert_param error has occurred.
     
274.   * @param  file: pointer to the source file name
     * m: X# d$ K3 f! S
275.   * @param  line: assert_param error line source number
     1 B; v! Q! }& j
276.   * @retval None
     - t8 o0 R4 n! G0 C( Z! }$ Z
277.   */
     ' h* l5 r& O/ C# B4 S
278. void assert_failed(uint8_t* file, uint32_t line)
     
279. {
     9 E5 j: L( ?7 ?  n) `; e+ D
280.   /* User can add his own implementation to report the file name and line number,
     . o% h5 m! \2 V: M) k. e1 ^) b
281.      ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
     
282. 
     . \2 v7 `; g+ ~$ g7 S) W' o
283.   /* Infinite loop */
     : p& \6 D7 H7 K8 z. d
284.   while (1)
     
285.   {
     ; H" P5 L$ }' b4 q7 b6 y! L& Y
286.   }
     ' w6 l1 a# |) r
287. }
     ! I$ Z  p% q" L4 Y$ K
288. #endif
     
289. 
     
290. /**
     
291.   * @brief  Configure the MPU attributes as Write Through for SRAM1/2.
     
292.   * @note   The Base Address is 0x20010000 since this memory interface is the AXI.
     
293.   *         The Region Size is 256KB, it is related to SRAM1 and SRAM2  memory size.
     / V7 U. b( j$ s7 e! W
294.   * @param  None
     
295.   * @retval None
     0 ~; {  J9 a$ B9 |, O
296.   */
     
297. static void MPU_Config(void)
     * c+ a0 z2 M  o2 U' g: T/ E2 c
298. {
     1 y4 O) N  ?! Z+ S) [. v
299.   MPU_Region_InitTypeDef MPU_InitStruct;
     
300.   
     
301.   /* Disable the MPU */
     " t! Z7 i8 a. Q. T. m; F) g; a. y0 l
302.   HAL_MPU_Disable();
     0 e7 J5 _8 M6 q) l
303. 
     * o. e: R+ x! A
304.   /* Configure the MPU attributes as WT for SRAM */
     , H! v- ^) @( l: w
305.   MPU_InitStruct.Enable = MPU_REGION_ENABLE;
     
306.   MPU_InitStruct.BaseAddress = 0x20010000;
     
307.   MPU_InitStruct.Size = MPU_REGION_SIZE_256KB;
     
308.   MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
     
309.   MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
     
310.   MPU_InitStruct.IsCacheable = MPU_ACCESS_CACHEABLE;
     
311.   MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE;
     0 I. S1 |" k; \  P; O
312.   MPU_InitStruct.Number = MPU_REGION_NUMBER0;
     
313.   MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
     2 @; [/ ]9 n" I$ Z+ Q& }
314.   MPU_InitStruct.SubRegionDisable = 0x00;
     
315.   MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;
     , S: w' F0 F6 ^2 e# e
316. 
     3 ^1 A' B' d/ Q7 @# w
317.   HAL_MPU_ConfigRegion(&MPU_InitStruct);
     - u. `; ~/ i  h2 K3 I9 u: {+ j8 y! L
318. 
     
319.   /* Enable the MPU */
     
320.   HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);
     ! w$ [5 ^# N7 A* [2 S% W
321. }
     ; T. e/ K( L3 u% j( k: p0 D
322. 
     
323. /**
     / C6 i9 N9 j6 _' z4 E( \; }
324.   * @brief  CPU L1-Cache enable.
     6 e* N; ?3 g  n/ F- n& U4 S- ^
325.   * @param  None
     
326.   * @retval None
     9 v$ ~5 T% K% y& W
327.   */
     
328. static void CPU_CACHE_Enable(void)
     
329. {
     0 W0 {1 W0 s( e& S: C1 c4 U6 i6 p
330.   /* Enable I-Cache */
     0 d: C+ S6 w# w, H7 {  V
331.   SCB_EnableICache();
     $ H" E$ R! T1 r0 {; {. j% m
332. 
     1 y, P2 F' X% n/ O' Y5 @1 S
333.   /* Enable D-Cache */
     % i) }5 w4 j* S: z
334.   SCB_EnableDCache();
     
335. }
     
336. 
     5 m, u( x# n' Q* L
337. /**
     8 j2 b- P3 Z9 \- X- g' _# D
338.   * @}
     : M; H8 p4 d" S0 K0 |) s! Q
339.   */
     7 w: @* l+ y- Y
340. 
     
341. /**
     & @/ J6 K! X! ^! J
342.   * @}“stdio.h”
       z0 \+ l6 k- X, `
343.   */
     : f; j& x: b3 `8 \* N; a; M3 R
344. 
     & w; j0 r# [( c7 V
345. /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/

复制代码

今天调试了stm32f407的ADC，一切顺利，然而用串口发送ADC结果时都是16进制数，看着很不爽。于是打算用用牛B的“printf”函数，按照以前的做法，在main文件中添加了“stdio.h”，写好了“printf”函数，沏杯茶，打算边品茶边坐等结果，然而这一坐竟坐了半天也没见结果

。一调试发现程序停在了printf函数处，百思不得其解，百度之，得答案，不敢独享，分享如下：
1 z2 t) }8 t9 Q1 \3 O! ?

STM32串口通信中使用printf发送数据配置方法(开发环境 Keil RVMDK)

标签: STM32 串口通信 printf方法 2011-06-29 23:29

在STM32串口通信程序中使用printf发送数据，非常的方便。可在刚开始使用的时候总是遇到问题，常见的是硬件访真时无法进入main主函数，其实只要简单的配置一下就可以了。

: N. l) Q. o' R) q2 k

下面就说一下使用printf需要做哪些配置。

有两种配置方法：

一、对工程属性进行配置，详细步骤如下

1、首先要在你的main 文件中 包含“stdio.h” （标准输入输出头文件）。

2、在main文件中重定义<fputc>函数 如下：

// 发送数据

int fputc(int ch, FILE *f)

{

USART_SendData(USART1, (unsigned char) ch);// USART1 可以换成 USART2 等

while (!(USART1->SR & USART_FLAG_TXE));

return (ch);

}

// 接收数据

int GetKey (void) {

while (!(USART1->SR & USART_FLAG_RXNE));

return ((int)(USART1->DR & 0x1FF));

}

这样在使用printf时就会调用自定义的fputc函数，来发送字符。

3、在工程属性的 “Target" -> "Code Generation" 选项中勾选 "Use MicroLIB"”

MicroLIB 是缺省C的备份库，关于它可以到网上查找详细资料。

& i4 {. a! k% L, W5 v* `& Z, S  `

至此完成配置，在工程中可以随意使用printf向串口发送数据了。

) V0 D9 H) ^0 L1 B

二、第二种方法是在工程中添加“Regtarge.c”文件

1、在main文件中包含 “stdio.h” 文件

2、在工程中创建一个文件保存为 Regtarge.c ， 然后将其添加工程中

在文件中输入如下内容（直接复制即可）

#include <stdio.h>

#include <rt_misc.h>

#pragma import(__use_no_semihosting_swi)

extern int SendChar(int ch); // 声明外部函数，在main文件中定义

extern int GetKey(void);

struct __FILE {

int handle; // Add whatever you need here

};

FILE __stdout;

FILE __stdin;

int fputc(int ch, FILE *f) {

return (SendChar(ch));

}

int fgetc(FILE *f) {

return (SendChar(GetKey()));

}

void _ttywrch(int ch) {

SendChar (ch);

}

int ferror(FILE *f) { // Your implementation of ferror

return EOF;

}

void _sys_exit(int return_code) {

label: goto label; // endless loop

}

3、在main文件中添加定义以下两个函数

int SendChar (int ch) {

while (!(USART1->SR & USART_FLAG_TXE)); // USART1 可换成你程序中通信的串口

USART1->DR = (ch & 0x1FF);

return (ch);

}

int GetKey (void) {

while (!(USART1->SR & USART_FLAG_RXNE));

return ((int)(USART1->DR & 0x1FF));

}