K60 UART模块的半双工模式

kingsings

    今天看参考手册，发现UART模块可以支持半双工模式，如下图所说：

发送端的引脚可以作为发送也可作为接收。
但我不明白的是，它是怎么保证发送的时候数据不被接收端接收？
还有一种是循环模式，内部将发送端接到接收端：

这个倒是可以理解。

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党国特派员

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anger0925

党国特派员 发表于 2015-9-13 21:40
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送1个        

kingsings

党国特派员 发表于 2015-9-13 21:40
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额，特派员怎么阔以这样。。

FSL_TICS_ZP

半双工也是串口的支持通信之一，通信原理建立楼主可以去度娘一下，例程代码分享如下：

1. 
   
2. 
   
3. int uart_single_wire_test()
   
4. {
   
5.     UART_MemMapPtr module1, module2;
   
6.     char ch;
   
7.     int error = 0;
   
8. 
   
9.     printf("\n\nStarting setup for UART single wire mode tests.\n");
   
10. 
    
11.     /* Determine which UART to use as module1 for testing. UART2 or UART3
    
12.      * could be used. We'll use UART2 as long as it isn't used as the TERM_PORT.
    
13.      */
    
14. 
    
15.   
    
16.        module1 = UART1_BASE_PTR;   // set the module pointer
    
17. 
    
18.       printf("\nUsing UART1 on the daughter card as module1.\n");
    
19. 
    
20. 
    
21.     /* Determine which UART to use as module2 for testing. UART4 or UART5
    
22.      * could be used. We'll use UART4 as long as it isn't used as the TERM_PORT.
    
23.      */
    
24.          
    
25.        module2 = UART3_BASE_PTR;   // set the module pointer
    
26. 
    
27.     printf("\nUsing UART3 on the daughter card as module2.\n");
    
28.    
    
29.     printf("Setup complete. Starting UART single wire mode tests...\n");
    
30. 
    
31.    
    
32.     /* Configure both UARTs for single wire mode */
    
33.   //  UART_C1_REG(module1) |= (UART_C1_LOOPS_MASK | UART_C1_RSRC_MASK);
    
34. //   UART_C1_REG(module2) |= (UART_C1_LOOPS_MASK | UART_C1_RSRC_MASK);
    
35. 
    
36.     /* Test sending data from module1 to module2 */
    
37.    
    
38.     /* Configure the module1 TXD pin as an output */
    
39.     UART_C3_REG(module1) |= UART_C3_TXDIR_MASK;
    
40.         /*
    
41.         //²âÊÔ·¢ËÍ
    
42.         while(1)
    
43.         {
    
44.                 uart_putchar(module1,0x01);
    
45.         }
    
46.         */
    
47.         
    
48.         /*
    
49.         //²âÊÔʹÓÃ:PC·¢Ë͸øUART3,uart3½«½ÓÊÕµÄÊý¾Ýͨ¹ýuart1»áËÍPC
    
50.         while(1)
    
51.         {
    
52.                   ch = uart_getchar(module2);
    
53.                    uart_putchar(module1,ch );
    
54.         
    
55.         }
    
56.         */
    
57.     uart_putchar(module1,0x01);
    
58. 
    
59.     /* Get the received data from module2 */
    
60.     ch = uart_getchar(module2);
    
61.    
    
62.     /* Test to make sure the data matches */
    
63.     if( ch != 0x01)
    
64.     {
    
65.         error++;
    
66.         printf("\nERR! Incorrect data received. Expected: 0xAA Recieved: 0x%02X", ch);
    
67.     }
    
68.    
    
69.     /* Make sure that module1 ignored the data (since it sent it) */
    
70.     if( uart_getchar_present(module1) )
    
71.     {
    
72.         error++;
    
73.         printf("\nERR! Data received on module1 when only module2 should have received.");
    
74.     }
    
75.       
    
76. 
    
77.     /* Test sending data from module2 to module1 */
    
78.    
    
79.     /* Configure the module1 TXD pin as an input */
    
80.     UART_C3_REG(module1) &= ~UART_C3_TXDIR_MASK;
    
81.    
    
82.     /* Configure the module2 TXD pin as an output */
    
83.     UART_C3_REG(module2) |= UART_C3_TXDIR_MASK;   
    
84.    
    
85.     uart_putchar(module2,0x55);
    
86.    
    
87.     /* Get the received data from module1 */
    
88.     ch = uart_getchar(module1);
    
89.    
    
90.     /* Test to make sure the data matches */
    
91.     if( ch != 0x55)
    
92.     {
    
93.         error++;
    
94.         printf("\nERR! Incorrect data received. Expected: 0x55 Recieved: 0x%02X", ch);
    
95.     }
    
96.    
    
97.     /* Make sure that module2 ignored the data (since it sent it) */
    
98.     if( uart_getchar_present(module2) )
    
99.     {
    
100.         error++;
     
101.         printf("\nERR! Data received on module2 when only module1 should have received.");
     
102.     }
     
103.    
     
104. 
     
105.     /* Clear TXDIR for both UARTs */
     
106.     UART_C3_REG(module1) &= ~UART_C3_TXDIR_MASK;
     
107.     UART_C3_REG(module2) &= ~UART_C3_TXDIR_MASK;
     
108. 
     
109.     /* Disable single wire mode for both UARTs*/
     
110. //   UART_C1_REG(module1) &= ~(UART_C1_LOOPS_MASK | UART_C1_RSRC_MASK);
     
111.   //  UART_C1_REG(module2) &= ~(UART_C1_LOOPS_MASK | UART_C1_RSRC_MASK);
     
112.     printf(" -------------------------endUART single wire mode tests-------------------------\n");
     
113. 
     
114. 
     
115. 
     
116.     return error;   
     
117. }     
     

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