//F020串口測試程序，全雙工通信
//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------

#include <c8051f020.h>                 // SFR declarations
#include <stdio.h>

//-----------------------------------------------------------------------------
// 16-bit SFR Definitions for 'F02x
//-----------------------------------------------------------------------------
sfr16 TMR3RL   = 0x92;                 // Timer3 reload value
sfr16 TMR3     = 0x94;                 // Timer3 counter               
sfr16 RCAP2    = 0xca;                 // Timer2 capture/reload
sfr16 T2       = 0xcc;                 // Timer2
//-----------------------------------------------------------------------------
// Global CONSTANTS
//-----------------------------------------------------------------------------

#define BAUDRATE     115200            // Baud rate of UART in bps
#define SYSCLK       22118400          // SYSCLK frequency in Hz
#define SAMPLE_RATE  50000             // Sample frequency in Hz
#define INT_DEC      256               // integrate and decimate ratio

sbit LED = P1^6;                       // LED='1' means ON
//-----------------------------------------------------------------------------
// Function PROTOTYPES
//-----------------------------------------------------------------------------

void SYSCLK_Init (void);
void PORT_Init (void);
void UART0_Init (void);
void Timer2_Init (int counts);
void UART0_ISR   (void);
void Timer1_Init(void);
//-----------------------------------------------------------------------------
// Global VARIABLES
//-----------------------------------------------------------------------------                          
unsigned char ning;
//-----------------------------------------------------------------------------
// MAIN Routine
//-----------------------------------------------------------------------------

void main (void) {
   WDTCN = 0xde;                       // disable watchdog timer
   WDTCN = 0xad;
   SYSCLK_Init ();               
   PORT_Init ();                       // initialize crossbar and GPIO
   UART0_Init ();                      // initialize UART0
   Timer2_Init (65536-(SYSCLK/SAMPLE_RATE/32/2));  //可選擇定時器1或2作為波特率發生器
   //Timer1_Init();
   ES0 =1;                                   // sample rat
   EA  =1;                        // Enable global interrupts
     LED = 0;
	while (1) {	                      // disable interrupts
      SBUF0 = 0x28;                   //要發送的數據，
	}
}

//-----------------------------------------------------------------------------
// SYSCLK_Init
//-----------------------------------------------------------------------------
//
// This routine initializes the system clock to use an 22.1184MHz crystal
// as its clock source.
//
void SYSCLK_Init (void)
{
   int i;                              // delay counter

   OSCXCN = 0x67;                      // start external oscillator with
                                       // 22.1184MHz crystal

   for (i=0; i < 256; i++) ;           // XTLVLD blanking interval (>1ms)

   while (!(OSCXCN & 0x80)) ;          // Wait for crystal osc. to settle

   OSCICN = 0x88;                      // select external oscillator as SYSCLK
                                       // source and enable missing clock
                                       // detector
}

//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
//
// Configure the Crossbar and GPIO ports
//
void PORT_Init (void)
{
   XBR0    = 0x04;                     // Enable UART0
   XBR1    = 0x00;
   XBR2    = 0x40;                     // Enable crossbar and weak pull-ups
   P0MDOUT |= 0x01;                    // enable TX0 as a push-pull output
   P1MDOUT |= 0x40;                    // enable P1.6 (LED) as push-pull output
}

//-----------------------------------------------------------------------------
// UART0_Init
//-----------------------------------------------------------------------------
//
// Configure the UART0 using Timer1, for <baudrate> and 8-N-1.
//
void UART0_Init (void)
{
   SCON0   = 0x50;                     // SCON0: mode 1, 8-bit UART, enable RX

}

//----------------------------------------------------------------------------
void Timer1_Init(void)
{
   TMOD    = 0x20;                     // TMOD: timer 1, mode 2, 8-bit reload
   TH1    = -(SYSCLK/BAUDRATE/16);     // set Timer1 reload value for baudrate
   TR1    = 1;                         // start Timer1
   CKCON |= 0x10;                  // Timer1 uses SYSCLK as time base
   PCON  |= 0x80;                      // SMOD00 = 1
}
    // TI0    = 1;                         // Indicate TX0 ready

//-----------------------------------------------------------------------------
// Timer3_Init
//-----------------------------------------------------------------------------
//
// Configure Timer3 to auto-reload at interval specified by <counts> (no 
// interrupt generated) using SYSCLK as its time base.
//
void Timer2_Init (int counts)
{  CKCON |= 0x20;  
   T2CON = 0x30;                      // Stop Timer3; Clear TF3;
                                       // use SYSCLK as timebase
   RCAP2  = counts;                  // Init reload values
   T2    =  counts;                    // set to reload immediately
                    
    TR2 = 1;
      
}
void UART0_ISR (void) interrupt 4
 {
   if(!TI0)               //是發送中斷還是接收中斷
  {
	RI0 = 0;
	ning =SBUF0; 
  if(ning==0x46)         //下位機接收的數據是否正確，正確就有指示燈取反（亮或滅）
    LED =~LED;           //0x46為上位機要發送的數據，可重新設置.
  }
 TI0 = 0; 
 
}