f00x_uart0_stdio.c

芯科原厂所有c8051fxx程序的例子。

//-----------------------------------------------------------------------------
// F00x_UART0_STDIO.c
//-----------------------------------------------------------------------------
// Copyright 2007 Silicon Laboratories, Inc.
// http://www.silabs.com
//
// Program Description:
//
// This program demonstrates how to configure the C8051F0xx to use routines
// in STDIO.h to write to and read from the UART interface.  The program
// reads a character using the STDIO routine getkey(), outputs that character
// to the screen, and then outputs the ASCII hex value of that character.
//
// Pinout
//
//    P0.0   digital   push-pull     UART TX
//    P0.1   digital   open-drain    UART RX
//    P1.6   digital   push-pull     LED
//
// How To Test:
//
// 1) Download code to a 'F0xx device that is connected to a UART transceiver
// 2) Connect serial cable from the transceiver to a PC
// 3) On the PC, open HyperTerminal (or any other terminal program) and connect
//    to the COM port at <BAUDRATE> and 8-N-1
// 4) HyperTerminal will print a message if everything is working properly
//
// Note: The designer must check that the required baud rate is reached and
//    that the error is within range for the application.
//
//
// Target:         C8051F0xx
// Tool chain:     KEIL C51 7.50 / KEIL EVAL C51
// Command Line:   None
//
// Release 1.0
//    -Initial Revision (CG / TP)
//    -07 DEC 2006
//
//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------

#include <C8051F000.h>                 // SFR declarations
#include <stdio.h>

//-----------------------------------------------------------------------------
// 16-bit SFR Definitions for 'F0xx
//-----------------------------------------------------------------------------

sfr16 RCAP2    = 0xCA;                 // Timer2 capture/reload
sfr16 TMR2     = 0xCC;                 // Timer2

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

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

// SYSCLK = System clock frequency in Hz

#define SYSCLK       22118400L         // SYSCLK in Hz

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

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

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

void main (void)
{
   unsigned char inputcharacter;

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

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

   UART0_Init ();                      // Initialize UART0

   while (1)
   {
      printf ("\nEnter character: ");
      inputcharacter = getkey ();
      printf ("\nCharacter entered : %c",inputcharacter);
      printf ("\n      Value in Hex: %bx",inputcharacter);
   }
}

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

//-----------------------------------------------------------------------------
// OSCILLATOR_Init
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters   : None
//
// This function initializes the system clock to use an external 22.1184MHz
// crystal.
//
//-----------------------------------------------------------------------------
void OSCILLATOR_Init (void)
{
   int i;                              // Software timer

   OSCICN |= 0x80;                     // Enable the missing clock detector

   // 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 1 ms
   while (!(OSCXCN & 0x80));           // Wait for crystal osc to settle

   OSCICN |= 0x08;                     // Select external clock source
   OSCICN &= ~0x04;                    // Disable the internal osc.
}

//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters   : None
//
// This function configures the crossbar and GPIO ports.
//
// Pinout:
//
// P0.0   digital   push-pull     UART TX
// P0.1   digital   open-drain    UART RX
//-----------------------------------------------------------------------------
void PORT_Init (void)
{
   XBR0     = 0x04;                    // Enable UART0
   XBR1     = 0x00;
   XBR2     = 0x40;                    // Enable crossbar and weak pull-up

   PRT0CF |= 0x01;                     // Set TX pin to push-pull
}

//-----------------------------------------------------------------------------
// 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)
{
   CKCON = 0x20;                       // Timer2 uses the system clock
   T2CON = 0x34;                       // Timer2 used for TX and RX, enabled
   RCAP2 = - ((long) (SYSCLK/BAUDRATE)/32);
   TMR2 = RCAP2;
   TR2= 1;                             // Start Timer2

   SCON = 0x50;                        // 8-bit variable baud rate;
                                       // 9th bit ignored; RX enabled
                                       // clear all flags
   TI = 1;                             // Indicate TX0 ready
}

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