f12x_uart0_interrupt.c

芯科原厂所有c8051fxx程序的例子。

//-----------------------------------------------------------------------------
// F12x_UART0_Interrupt.c
//-----------------------------------------------------------------------------
// Copyright 2006 Silicon Laboratories, Inc.
// http://www.silabs.com
//
// Program Description:
//
// This program demonstrates how to configure the C8051F120 to write to and read 
// from the UART interface. The program reads a word using the UART0 interrupts 
// and outputs that word to the screen, with all characters in uppercase
//
// How To Test:
//
// 1) Download code to a 'F12x device that is connected to a UART transceiver
// 2) Verify jumpers J6 and J9 are populated on the 'F12x TB.
// 3) Connect serial cable from the transceiver to a PC
// 4) On the PC, open HyperTerminal (or any other terminal program) and connect
//    to the COM port at <BAUDRATE> and 8-N-1
// 5) Download and execute code on an 'F12x target board.
// 6) Type up to 64 characters into the Terminal and press Enter.  The MCU 
//    will then print back the characters that were typed
//   
//
// Target:         C8051F12x
// Tool chain:     Keil C51 7.50 / Keil EVAL C51
// Command Line:   None
//
// Release 1.0
//    -Initial Revision (SM)
//    -11 JULY 2007
//


//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------

#include <c8051f120.h>                 // SFR declarations
#include <stdio.h>                     

//-----------------------------------------------------------------------------
// 16-bit SFR Definitions for 'F12x
//-----------------------------------------------------------------------------

sfr16 RCAP2    = 0xca;                 // Timer2 capture/reload
sfr16 TMR2     = 0xcc;                 // Timer2

//-----------------------------------------------------------------------------
// Global Constants
//-----------------------------------------------------------------------------

#define BAUDRATE     115200            // Baud rate of UART in bps

// SYSTEMCLOCK = System clock frequency in Hz
#define SYSTEMCLOCK       (22118400L * 9 / 4)

//-----------------------------------------------------------------------------
// Function Prototypes
//-----------------------------------------------------------------------------

void OSCILLATOR_Init (void);         
void PORT_Init (void);
void UART0_Init (void);

//-----------------------------------------------------------------------------
// Global Variables
//-----------------------------------------------------------------------------

#define UART_BUFFERSIZE 64
unsigned char UART_Buffer[UART_BUFFERSIZE];
unsigned char UART_Buffer_Size = 0; 
unsigned char UART_Input_First = 0;
unsigned char UART_Output_First = 0;
unsigned char TX_Ready =1;
static char Byte;

//-----------------------------------------------------------------------------
// main() Routine
//-----------------------------------------------------------------------------

void main (void)
{
     
   SFRPAGE = CONFIG_PAGE;

   WDTCN = 0xDE;                       // Disable watchdog timer
   WDTCN = 0xAD;

   OSCILLATOR_Init ();                 // Initialize oscillator
   PORT_Init ();                       // Initialize crossbar and GPIO

   UART0_Init ();                      // Initialize UART0
   
   EA = 1;

   SFRPAGE = UART0_PAGE;   

   while (1)
   {  
      // If the complete word has been entered via the terminal followed 
      // by carriage return
      if((TX_Ready == 1) && (UART_Buffer_Size != 0) && (Byte == 13))  
	  { 
         TX_Ready = 0;                  // Set the flag to zero
         TI0 = 1;                       // Set transmit flag to 1
	  }         
   }
}

//-----------------------------------------------------------------------------
// Initialization Subroutines
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// OSCILLATOR_Init
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters   : None
//
// This function initializes the system clock to use the PLL as its clock
// source, where the PLL multiplies the external 22.1184MHz crystal by 9/4.
//
//-----------------------------------------------------------------------------
void OSCILLATOR_Init (void)
{
   int i;                              // Software timer

   char SFRPAGE_SAVE = SFRPAGE;        // Save Current SFR page

   SFRPAGE = CONFIG_PAGE;              // Set SFR page

   OSCICN = 0x80;                      // Set internal oscillator to run
                                       // at its slowest frequency

   CLKSEL = 0x00;                      // Select the internal osc. as
                                       // the SYSTEMCLOCK source

   // Initialize external crystal oscillator to use 22.1184 MHz crystal

   OSCXCN = 0x67;                      // Enable external crystal osc.
   for (i=0; i < 256; i++);            // Wait at least 1ms

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

   SFRPAGE = LEGACY_PAGE;
   FLSCL |=  0x30;                     // Initially set FLASH read timing for
                                       // 100MHz SYSTEMCLOCK (most conservative
                                       // setting)
   if (SYSTEMCLOCK <= 25000000) {           
   // Set FLASH read timing for <=25MHz
      FLSCL &= ~0x30;
   } else if (SYSTEMCLOCK <= 50000000) {    
   // Set FLASH read timing for <=50MHz
      FLSCL &= ~0x20;
   } else if (SYSTEMCLOCK <= 75000000) {    
   // Set FLASH read timing for <=75MHz
      FLSCL &= ~0x10;
   } else {                            // set FLASH read timing for <=100MHz
      FLSCL &= ~0x00;
   }

   // Start PLL for 50MHz operation
   SFRPAGE = PLL0_PAGE;
   PLL0CN = 0x04;                      // Select EXTOSC as clk source
   PLL0CN |= 0x01;                     // Enable PLL power
   PLL0DIV = 0x04;                     // Divide by 4
   PLL0FLT &= ~0x0f;
   PLL0FLT |=  0x0f;                   // Set Loop Filt for (22/4)MHz input clock
   PLL0FLT &= ~0x30;                   // Set ICO for 30-60MHz
   PLL0FLT |=  0x10;

   PLL0MUL = 0x09;                     // Multiply by 9

   // wait at least 5us
   for (i = 0; i < 256; i++) ;

   PLL0CN |= 0x02;                     // Enable PLL

   while (PLL0CN & 0x10 == 0x00);      // Wait for PLL to lock

   SFRPAGE = CONFIG_PAGE;

   CLKSEL = 0x02;                      // Select PLL as SYSTEMCLOCK source

   SFRPAGE = SFRPAGE_SAVE;             // Restore SFRPAGE
}


//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters   : None
//
// This function configures the crossbar and GPIO ports.
//
// P0.0   digital   push-pull     UART TX
// P0.1   digital   open-drain    UART RX
//-----------------------------------------------------------------------------
void PORT_Init (void)
{
   char SFRPAGE_SAVE = SFRPAGE;        // Save Current SFR page

   SFRPAGE = CONFIG_PAGE;              // Set SFR page

   XBR0     = 0x04;                    // Enable UART0
   XBR1     = 0x00;
   XBR2     = 0x40;                    // Enable crossbar and weak pull-up
                                       

   P0MDOUT |= 0x01;                    // Set TX pin to push-pull
   P1MDOUT |= 0x40;                    // Set P1.6(LED) to push-pull

   SFRPAGE = SFRPAGE_SAVE;             // Restore SFR page
}


//-----------------------------------------------------------------------------
// UART0_Init   Variable baud rate, Timer 2, 8-N-1
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters   : None
//
// Configure UART0 for operation at <baudrate> 8-N-1 using Timer2 as
// baud rate source.
//
//-----------------------------------------------------------------------------
void UART0_Init (void)
{
   char SFRPAGE_SAVE;

   SFRPAGE_SAVE = SFRPAGE;             // Preserve SFRPAGE

   SFRPAGE = TMR2_PAGE;

   TMR2CN = 0x00;                      // Timer in 16-bit auto-reload up timer
                                       // mode
   TMR2CF = 0x08;                      // SYSCLK is time base; no output;
                                       // up count only
   RCAP2 = - ((long) SYSTEMCLOCK/BAUDRATE/16);
   TMR2 = RCAP2;
   TR2= 1;                             // Start Timer2

   SFRPAGE = UART0_PAGE;

   SCON0 = 0x50;                       // 8-bit variable baud rate;
                                       // 9th bit ignored; RX enabled
                                       // clear all flags
   SSTA0 = 0x15;                       // Clear all flags; enable baud rate
                                       // doubler (not relevant for these
                                       // timers);
                                       // Use Timer2 as RX and TX baud rate
                                       // source;
   ES0 = 1;  
   IP |= 0x10;

   SFRPAGE = SFRPAGE_SAVE;             // Restore SFRPAGE
}


//-----------------------------------------------------------------------------
// Interrupt Service Routines
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// UART0_Interrupt
//-----------------------------------------------------------------------------
//
// This routine is invoked whenever a character is entered or displayed on the
// Hyperterminal.
//
//-----------------------------------------------------------------------------

void UART0_Interrupt (void) interrupt 4
{
   SFRPAGE = UART0_PAGE;

   if (RI0 == 1)
   {
      if( UART_Buffer_Size == 0)  {      // If new word is entered
         UART_Input_First = 0;    }

      RI0 = 0;                           // Clear interrupt flag

      Byte = SBUF0;                      // Read a character from UART

      if (UART_Buffer_Size < UART_BUFFERSIZE)
      {
         UART_Buffer[UART_Input_First] = Byte; // Store in array

         UART_Buffer_Size++;             // Update array's size

         UART_Input_First++;             // Update counter
      }
   }

   if (TI0 == 1)                   // Check if transmit flag is set
   {
      TI0 = 0;                           // Clear interrupt flag

      if (UART_Buffer_Size != 1)         // If buffer not empty
      {
         // If a new word is being output
         if ( UART_Buffer_Size == UART_Input_First ) {
              UART_Output_First = 0;  }

         // Store a character in the variable byte
         Byte = UART_Buffer[UART_Output_First];

         if ((Byte >= 0x61) && (Byte <= 0x7A)) { // If upper case letter
            Byte -= 32; }

         SBUF0 = Byte;                   // Transmit to Hyperterminal

         UART_Output_First++;            // Update counter

         UART_Buffer_Size--;             // Decrease array size

      }
      else
      {
         UART_Buffer_Size = 0;            // Set the array size to 0
         TX_Ready = 1;                    // Indicate transmission complete
      }
   }
}

//-----------------------------------------------------------------------------
// End Of File
//-----------------------------------------------------------------------------