演示STC89xx系列单片机串行口功能 (8-bit/9-bit)

Posted 2020-11-09 互联星空

  1 /*------------------------------------------------------------------------------------*/
  2 /* --- STC MCU Limited ---------------- ---------------------------------------*/
  3 /* ---演示STC89xx系列单片机串行口功能  (8-bit/9-bit) ----------------*/
  4 /* --- Mobile: [phone] -----------------------------------------------*/
  5 /* --- Fax: [phone] ---------------------------------------------------*/
  6 /* --- Tel: [phone] ----------------------------------------------------*/
  7 /* --- Web: www.STCMCU.com -----------------------------------------------*/
  8 /*如果要在程序中使用?在文章中引用该程序，   -----------------------*/
  9 /*请在程序中?文章中注明使用了STC的资料及程序   -----------*/
 10 /*-------------------------------------------------------------------------------------*/
 11 #include "reg51.h"
 12 #include "intrins.h"
 13 
 14 typedef unsigned char    BYTE;
 15 typedef unsigned int    WORD;
 16 
 17 #define FOSC    18432000L       /* System frequency 系统频率 */
 18 #define BAUD    9600            /* UART baudrate 波特率 */
 19 
 20 
 21 /*Define UART parity mode*/
 22 #define NONE_PARITY    0       /* None parity 奇偶*/
 23 #define ODD_PARITY    1       /* Odd parity 奇*/
 24 #define EVEN_PARITY    2       /* Even parity 偶*/
 25 #define MARK_PARITY    3       /* Mark parity */
 26 #define SPACE_PARITY 4       /* Space parity */
 27 
 28 
 29 #define PARITYBIT EVEN_PARITY   /* Testing even parity 测试*/
 30 
 31 sbit    bit9 = P2 ^ 2;          /* P2.2 show UART data bit9 */
 32 bit    busy;
 33 
 34 void SendData( BYTE dat );
 35 
 36 
 37 void SendString( char *s );
 38 
 39 
 40 void main()
 41 {
 42 #if (PARITYBIT == NONE_PARITY)
 43     SCON = 0x50;                                    /* 8-bit variable UART */
 44 
 45 #elif (PARITYBIT == ODD_PARITY) || (PARITYBIT == EVEN_PARITY) || (PARITYBIT == MARK_PARITY)
 46     SCON = 0xda;                                    /* 9-bit variable UART, parity bit initial to 1 */
 47 #elif (PARITYBIT == SPACE_PARITY)
 48     SCON = 0xd2;                                    /* 9-bit variable UART, parity bit initial to 0 */
 49 
 50 
 51 #endif
 52 
 53     TMOD    = 0x20;                                 /* Set Timer1 as 8-bit auto reload mode */
 54     //TH1    = TL1 = -(FOSC/12/32/BAUD);       /* Set auto-reload vaule */
 55     TH1    = 0xfd; 
 56     TL1    = 0xfd;
 57     TR1    = 1;                                    /* Timer1 start run */
 58     ES    = 1;                                    /* Enable UART interrupt */
 59     EA    = 1;                                    /* Open master interrupt switch */
 60 
 61     SendString( "STC89-90xx\r\nUart Test !\r\n" );
 62     while ( 1 );
 63 }
 64 
 65 
 66 /*----------------------------
 67 *  UART interrupt service routine
 68 *  ----------------------------*/
 69 void Uart_Isr() interrupt 4 using 1
 70 {
 71     if ( RI )
 72     {
 73         RI    = 0;    /* Clear receive interrupt flag */
 74         P0    = SBUF; /* P0 show UART data */
 75         bit9    = RB8;  /* P2.2 show parity bit */
 76     }
 77 
 78 
 79     if ( TI )
 80     {
 81         TI    = 0;    /* Clear transmit interrupt flag */
 82         busy    = 0;    /* Clear transmit busy flag */
 83     }
 84 }
 85 
 86 
 87 /*----------------------------
 88 *  Send a byte data to UART
 89 *  Input: dat (data to be sent)
 90 *  Output:None
 91 *  ----------------------------*/
 92 void SendData( BYTE dat )
 93 {
 94     while ( busy );               /* Wait for the completion of the previous data is sent */
 95     ACC = dat;              /* Calculate the even parity bit P (PSW.0) */
 96     if ( P )                /* Set the parity bit according to P */
 97 
 98 
 99     {
100 #if (PARITYBIT == ODD_PARITY)
101         TB8 = 0;        /* Set parity bit to 0 */
102 #elif (PARITYBIT == EVEN_PARITY)
103         TB8 = 1;        /* Set parity bit to 1 */
104 
105 
106 #endif
107     }else  {
108 #if (PARITYBIT == ODD_PARITY)
109         TB8 = 1;        /* Set parity bit to 1 */
110 #elif (PARITYBIT == EVEN_PARITY)
111         TB8 = 0;        /* Set parity bit to 0 */
112 #endif
113     }
114     busy    = 1;
115     SBUF    = ACC;          /* Send data to UART buffer */
116 }
117 
118 
119 /*----------------------------
120 *  Send a string to UART
121 *  Input: s (address of string)
122 *  Output:None
123 *  ----------------------------*/
124 void SendString( char *s )
125 {
126     while ( *s )                    /* Check the end of the string */
127 
128     {
129         SendData( *s++ );       /* Send current char and increment string ptr */
130     }
131 }