UART.rar_c8051f040 UART

/*************************************************************************/ /*******************************程序说明**********************************/ //1.UART0采用方式1: 即异步通信，8个数据位，1个起始位和一个停止位。 //2.UART0的时钟源选取Timer1，工作在8位自动重装载方式。 //3.Timer1的时钟源选取外部晶振22.1184MHz. //4.UART0的波特率为9600. //5.UART0的TXD,RXD引脚分别为P0.0和P0.1 /*************************************************************************/ #include <c8051f040.h> #define BAUDRATE 9600 #define TIMER1_OVERFLOW_RATE BAUDRATE * 32 #define EXTERNAL_OSCILLATOR 22118400 #define TIMER1_CLK EXTERNAL_OSCILLATOR / 8 #define TIMER1_RELOAD_VALUE 256 - TIMER1_CLK / TIMER1_OVERFLOW_RATE sbit LED2=P4^1; // LED1 ='0' means ON sbit LED3=P4^0; sbit S2=P4^3; // SW1 ='0' means switch pressed sbit S3=P4^2; void IO_Init(void) { unsigned char SFRPAGE_SAVE = SFRPAGE; SFRPAGE = CONFIG_PAGE; XBR0 = 0x04; //Eable UART0 XBR2 = 0x40; //Eable Crossbar and weak Pull-ups. P0MDOUT |= 0x01; //Set TX0 pin to push-pull SFRPAGE = SFRPAGE_SAVE; } void Oscillator_Init(void) { unsigned char SFRPAGE_SAVE = SFRPAGE; int i = 0; //i for software delay SFRPAGE = CONFIG_PAGE; OSCICN = 0x83; //Set Internal Oscillator frequency 24.5MHz CLKSEL = 0x00; //Select Internal Oscillator as SYSCLK OSCXCN = 0x67; //Eable External Oscillator 22.1184MHz for (i = 0; i < 3000; i++); //Wait 1ms for initialization while ((OSCXCN & 0x80) == 0); SFRPAGE = SFRPAGE_SAVE; } void Timer_Init(void) { unsigned char SFRPAGE_SAVE = SFRPAGE; SFRPAGE = TIMER01_PAGE; TMOD = 0x20; CKCON = 0x03; TH1 = 247; TL1 = TH1; TR1 = 1; //Start Timer1 SFRPAGE = SFRPAGE_SAVE; } void UART0_Init(void) { unsigned char SFRPAGE_SAVE = SFRPAGE; SFRPAGE = UART0_PAGE; SCON0 = 0x50; TI0 = 1; //Indicate TX0 Ready. RI0 = 0; //Indicate RX0 Ready. SFRPAGE = SFRPAGE_SAVE; } void UART0_Tx_uchar8(unsigned char i) { unsigned char SFRPAGE_SAVE = SFRPAGE; SFRPAGE = UART0_PAGE; while( (TI0==0) || (RI0==1) ); //Wait until TX0 and RX0 Ready. TI0 = 0; SBUF0 = i; SFRPAGE = SFRPAGE_SAVE; } void UART0_Tx_String(unsigned char *p_string) { while(*p_string) { UART0_Tx_uchar8(*p_string); p_string++; } } void main(void) { bit key2_down_flag=0; bit key3_down_flag=0; SFRPAGE = CONFIG_PAGE; WDTCN = 0xde; //Disable watchdog timer WDTCN = 0xad; IO_Init(); Oscillator_Init(); Timer_Init(); UART0_Init(); while (1) { if (S2 == 0) { if (key2_down_flag==0) { UART0_Tx_uchar8('a'); UART0_Tx_uchar8('b'); UART0_Tx_uchar8('c'); key2_down_flag = 1; LED2=0; } } else { key2_down_flag = 0; LED2=1; } if (S3 == 0) { if (key3_down_flag==0) { UART0_Tx_String("Hello World!\n\r"); key3_down_flag = 1; LED3=0; } } else { key3_down_flag = 0; LED3=1; } } }