blinky.c

来自「8051试验程序 基础教材」· C语言 代码 · 共 140 行

//-----------------------------------------------------------------------------
// Blinky.c
//-----------------------------------------------------------------------------
// Copyright 2007 Silicon Laboratories, Inc.
// http://www.silabs.com
//
// Program Description:
//
// This program flashes the green LED on the C8051T60x target board about
// five times a second using the interrupt handler for Timer2.
//
// FID:
// Target:         C8051T60x
// Tool chain:     IAR Systems EW8051 v7.21
// Command Line:   None

//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------
#include <ioC8051T600.h>            // SFR declarations


//-----------------------------------------------------------------------------
// Global CONSTANTS
//-----------------------------------------------------------------------------

#define SYSCLK       24500000 / 8      // SYSCLK frequency in Hz

#define LED P0_bit.P0_6                       // LED='1' means ON
#define SW1 P0_bit.P0_3                       // SW1='0' means switch pressed

//-----------------------------------------------------------------------------
// 16-bit SFR Definitions for 'T60x
//-----------------------------------------------------------------------------

__sfr __no_init volatile unsigned short TMR2RL @ 0xCA;
__sfr __no_init volatile unsigned short TMR2   @ 0xCC;

//-----------------------------------------------------------------------------
// Function PROTOTYPES
//-----------------------------------------------------------------------------
void SYSCLK_Init (void);
void PORT_Init (void);
void Timer2_Init (int counts);
__interrupt void Timer2_ISR (void);

//-----------------------------------------------------------------------------
// MAIN Routine
//-----------------------------------------------------------------------------
void main (void) {

   // disable watchdog timer
   PCA0MD &= ~0x40;                    // WDTE = 0 (clear watchdog timer
                                       // enable)

   SYSCLK_Init ();                     // Initialize system clock to
                                       // 24.5MHz
   PORT_Init ();                       // Initialize crossbar and GPIO
   Timer2_Init (SYSCLK / 12 / 10);     // Init Timer2 to generate
                                       // interrupts at a 10Hz rate.

   IE_bit.EA = 1;                             // enable global interrupts

   while (1) {                         // spin forever
   }
}

//-----------------------------------------------------------------------------
// SYSCLK_Init
//-----------------------------------------------------------------------------
//
// This routine initializes the system clock to use the internal 24.5MHz / 8
// oscillator as its clock source.  Also enables missing clock detector reset.
//
void SYSCLK_Init (void)
{
   OSCICN = 0x04;                      // configure internal oscillator for
                                       // its lowest frequency
   RSTSRC = 0x04;                      // enable missing clock detector
}

//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
//
// Configure the Crossbar and GPIO ports.
// P0.0 -
// P0.1 -
// P0.2 -
// P0.3 - SW1
// P0.4 -
// P0.5 -
// P0.6 - LED (push-pull)
// P0.7 - C2D
//
void PORT_Init (void)
{
   XBR0     = 0x40;                    // skip P0.6 (LED) in crossbar pin
                                       // assignments
   XBR1     = 0x00;                    // no digital peripherals selected
   XBR2     = 0x40;                    // Enable crossbar and weak pull-ups
   P0MDOUT |= 0x40;                    // enable LED as a push-pull output
}

//-----------------------------------------------------------------------------
// Timer2_Init
//-----------------------------------------------------------------------------
//
// Configure Timer2 to 16-bit auto-reload and generate an interrupt at
// interval specified by <counts> using SYSCLK/48 as its time base.
//
void Timer2_Init (int counts)
{
   TMR2CN  = 0x00;                     // Stop Timer2; Clear TF2;
                                       // use SYSCLK/12 as timebase
   CKCON  &= ~0x60;                    // Timer2 clocked based on T2XCLK;

   TMR2RL  = -counts;                  // Init reload values
   TMR2    = 0xffff;                   // set to reload immediately
   IE_bit.ET2     = 1;                 // enable Timer2 interrupts
   TMR2CN_bit.TR2 = 1;                 // start Timer2
}

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

//-----------------------------------------------------------------------------
// Timer2_ISR
//-----------------------------------------------------------------------------
// This routine changes the state of the LED whenever Timer2 overflows.
//

#pragma vector=0x02B
__interrupt void Timer2_ISR (void)
{
   TMR2CN_bit.TF2H = 0;                // clear Timer2 interrupt flag
   LED = ~LED;                         // change state of LED
}