Mini2440串口.doc

Mini2440串口CMini2440有三个串口，USRT0,UART1,UART3。对串口的操作有三种：串口初始化，串口接收，串口发送1 串口初始化1）串口初始化函数void Uart_Init(int pclk,int baud)int i;if(pclk = 0)pclk= PCLK;rUFCON0 = 0x0; /UART channel 0 FIFO control register, FIFO disablerUFCON1 = 0x0; /UART channel 1 FIFO control register, FIFO disablerUFCON2 = 0x0; /UART channel 2 FIFO control register, FIFO disablerUMCON0 = 0x0; /UART chaneel 0 MODEM control register, AFC disablerUMCON1 = 0x0; /UART chaneel 1 MODEM control register, AFC disable/UART0rULCON0 = 0x3; /Line control register : Normal,No parity,1 stop,8 bits /10 9 8765 4 3:21:0 / Clock Sel,Tx Int,Rx Int, Rx Time Out, Rx err, Loop-back, Send break,Transmit Mode, Receive Mode / 01 0, 010 0 , 0101 / PCLK LevelPulseDisableGenerateNormalNormalInterrupt or PollingrUCON0= 0x245; / Control registerrUBRDIV0=( (int)(pclk/16./baud+0.5) -1 ); /Baud rate divisior register 0/UART1rULCON1 = 0x3;rUCON1= 0x245;rUBRDIV1=( (int)(pclk/16./baud+0.5) -1 );/UART2rULCON2 = 0x3;rUCON2= 0x245;rUBRDIV2=( (int)(pclk/16./baud+0.5) -1 );for(i=0;i100;i+);l 串口时钟的设置pclk= PCLK;使用PCLK作为串口的时钟。l 寄存器进行了设置主要是对三种寄存器进行了设置rUFCONn (n=0,1,2) 串口FIFO控制寄存器rUMCONn (n=0,1)串口调制控制寄存器rULCONn (n=0,1,2)串口线性控制寄存器rUCONn(n=0,1,2)串口控制寄存器rUBRDIVn(n=0,1,2)串口Tx,Rx收发速率的设定2）串口的选择void Uart_Select(int ch)whichUart = ch;2 串口发送串口发送数据通过判断rUTRSTATn (n=0,1,2)的第2位是不是为1来判断发送缓存是否为空。1）串口发送字节void Uart_SendByte(int data)if(whichUart=0)if(data=/n)while(!(rUTRSTAT0 & 0x2); / Delay(1); /because the slow response of hyper_terminalWrUTXH0(/r);while(!(rUTRSTAT0 & 0x2); /Wait until THR is empty./Delay(1);WrUTXH0(data);else if(whichUart=1)if(data=/n)while(!(rUTRSTAT1 & 0x2);/Delay(1); /because the slow response of hyper_terminalrUTXH1 = /r;while(!(rUTRSTAT1 & 0x2); /Wait until THR is empty./Delay(1);rUTXH1 = data;else if(whichUart=2)if(data=/n)while(!(rUTRSTAT2 & 0x2);/Delay(1); /because the slow response of hyper_terminalrUTXH2 = /r;while(!(rUTRSTAT2 & 0x2); /Wait until THR is empty./Delay(1);rUTXH2 = data;首先是串口通道的选择；然后判断THR是否为空，直到等到发送缓存为空，退出while循环；再要发送的字节data放到发送缓存中。如果发送的数据是回车的话，直接发送转义字符/r，当然也要等到THR为空才可以发送。2）串口发送字符串void Uart_SendString(char *pt)while(*pt)Uart_SendByte(*pt+);把字符串看作是字符数组，字符指针*pt来指代字符数组的首地址，读取指针指向的字符，这样就可以把发送的的字符串逐个进行字节发送了。2 串口接收串口接收通过判断rUTRSTATn (n=0,1,2)的第1位是不是为1来判断发送缓存是否为空。1）串口等待接收状态void Uart_TxEmpty(int ch)if(ch=0)while(!(rUTRSTAT0 & 0x4); /Wait until tx shifter is empty.else if(ch=1)while(!(rUTRSTAT1 & 0x4); /Wait until tx shifter is empty.else if(ch=2)while(!(rUTRSTAT2 & 0x4); /Wait until tx shifter is empty.寄存器rUTRSTATn & 0x4 (n=0,1,2)来判断tx shifter是不是为空3）接收字符char Uart_Getch(void)if(whichUart=0)while(!(rUTRSTAT0 & 0x1); /Receive data readyreturn RdURXH0();else if(whichUart=1)while(!(rUTRSTAT1 & 0x1); /Receive data readyreturn RdURXH1();else if(whichUart=2)while(!(rUTRSTAT2 & 0x1); /Receive data readyreturn RdURXH2();return 0 ;寄存器rUTRSTATn & 0x1(n=0,1,2)来判断Receive data ready？并把接收到的数据写到接收缓存里面。4）接收字符串void Uart_GetString(char *string)char *string2 = string;char c;while(c = Uart_Getch()!=/r)if(c=/b)if( (int)string2 (int)string )Uart_Printf(/b /b);string-;else*string+ = c;Uart_SendByte(c);*string=/0;Uart_SendByte(/n);char Uart_GetKey(void)if(whichUart=0)if(rUTRSTAT0 & 0x1)/Receive data readyreturn RdURXH0();elsereturn 0;else if(whichUart=1)if(rUTRSTAT1 & 0x1)/Receive data readyreturn RdURXH1();elsereturn 0;else if(whichUart=2)if(rUTRSTAT2 & 0x1)/Receive data readyreturn RdURXH2();elsereturn 0;return 0 ;寄存器rUTRSTATn & 0x1 (n=0,1,2)来判断Receive data ready？并把接收到的数据写到接收缓存里面。否则返回空。与getchar类似，并且也是返回字符类型。5）接收整形数字函数返回类型：整形int Uart_GetIntNum(void)char str30;char *string = str;int base = 10;int minus= 0;int result = 0;int lastIndex;int i;Uart_GetString(string);if(string0=-)minus = 1;string+;if(string0=0 & (string1=x | string1=X)base= 16;string += 2;lastIndex = strlen(string) - 1;if(lastIndex0)return -1;if(stringlastIndex=h | stringlastIndex=H )base = 16;stringlastIndex = 0;lastIndex-;if(base=10)result = atoi(string);result = minus ? (-1*result):result;elsefor(i=0;i=lastIndex;i+)if(isalpha(string)if(isupper(string)result = (result4) + string- A + 10;elseresult = (result4) + string- a + 10;elseresult = (result4) + string- 0;result = minus ? (-1*result):result;return result;首先以字符串的形式接收数据Uart_GetString(string);然后通过判断是不是以-开头来确定是不是负数，是负数则minus=1；再通过以0x,oX开头或者以H,h结尾来判断是不是16进制，否则为10进制；如果是10进制，则通过atoi把字符串转化为数字，并加上正负，如果是16进制，判断是不是字母，再判断大小写字母分别进行转换。16进制也支持正负号。6）接收10进制的数int Uart_GetIntNum_GJ(void)char string16 ;char *p_string = string ;char c;int i = 0 ;int data = 0 ;while( ( c = Uart_Getch() != /r) if(c=/b) p_string-; else *p_string+=c; Uart_SendByte( c ) ;*p_string = /0;i = 0 ;while( string!= /0 ) data = data * 10 ; if( string9 ) return -1 ; data = data + ( string-0 ) ; i+ ;return data ;只转化10进制的数字。首先用getchar接收单个字符存储在string中，然后把string转换为整型的data。并返回整形的data。3串口打印/If you dont use vsprintf(), the code size is reduced very much.void Uart_Printf(char *fmt,.)va_list ap;char string256;va_start(ap,fmt);vsprintf(string,fmt,ap);Uart_SendString(string);va_end(ap);va_list完成可变参数的操作具体实现如下n 由于无法列出传递函数的所有实参的类型和数目时,用省略号指定参数表void Uart_Printf(char *fmt,.)n 函数参数的传递原理函数参数是以数据结构:栈的形式存取,从右至左入栈.n 获取省略号指定的参数在函数体中声明一个va_list，