f53xa_timer0_two_8bittimers.c

c8051f52X单片机的定时器的源代码

//-----------------------------------------------------------------------------
// F53xA_Timer2_two_8bitTimers.c
//-----------------------------------------------------------------------------
// Copyright 2007 Silicon Laboratories, Inc.
// http://www.silabs.com
//
// Program Description:
//
// This program presents an example of use of the Timer2 of the C8051F53xA's in
// two 8-bit reload counter/timer mode. It uses the 'F530A TB as the HW
// platform.
//
// It sets Timer2 to be two 8-bit timers that interrupt every millisecond.
//
// When the Timer2 low interrupts a counter (low_counter) increments and upon
// reaching the value defined by LED_TOGGLE_RATE toggles the LED.
// When the Timer2 high interrupts a counter (high_counter) increments and upon
// reaching the value defined by SIGNAL_TOGGLE_RATE toggles the SIGNAL pin.
//
// Pinout:
//
//    P1.3 -> LED (toggled by TMR2L)
//
//    P1.7 -> SIGNAL (toggled by TMR2H)
//
//    all other port pins unused
//
// How To Test:
//
// 1) Open the F53xA_Timer2_two_8bitTimers.c file in the Silicon Labs IDE.
// 2) If necessary change the number of interrupts to toggle an output:
//    LED_TOGGLE_RATE
//    SIGNAL_TOGGLE_RATE
// 3) Compile the project.
// 4) Download code to a 'F53xA device (either device A or B on the TB).
// 5) Verify the LED jumper is populated (HDR4 for device A and HDR3 for
//    device B).
// 6) If using device A on the TB, verify the P1.7 jumper (J4) is installed.
// 7) Run the code.
// 8) Verify that the LED is blinking and SIGNAL is toggling.
//
//
// Target:         C8051F52xA/F53xA (C8051F530A TB)
// Tool chain:     KEIL C51 7.20 / KEIL EVAL C51
// Command Line:   None
//
// Release 1.1
//    -Updated for 'F530A TB (TP)
//    -31 JAN 2008
//
// Release 1.0
//    -Initial Revision (SM)
//    -11 JUN 2007
//


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

#include "compiler_defs.h"
#include "C8051F520A_defs.h"

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

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

#define TIMER_PRESCALER            48  // Based on Timer CKCON settings

// There are SYSCLK/TIMER_PRESCALER timer ticks per second, so
// SYSCLK/TIMER_PRESCALER/1000 timer ticks per millisecond.
#define TIMER_TICKS_PER_MS  SYSCLK/TIMER_PRESCALER/1000

// Note: TIMER_TICKS_PER_MS should not exceed 255 (0xFF) for the 8-bit timers

#define AUX1     TIMER_TICKS_PER_MS
#define AUX2     -AUX1

#define LED_TOGGLE_RATE           100  // LED toggle rate in milliseconds
                                       // if LED_TOGGLE_RATE = 1, the LED will
                                       // be on for 1 millisecond and off for
                                       // 1 millisecond

#define SIGNAL_TOGGLE_RATE         30  // SIGNAL pin toggle rate in
                                       // milliseconds
                                       // if SIGNAL_TOGGLE_RATE = 1, the
                                       // SIGNAL output will be on for 1
                                       // millisecond and off for 1
                                       // millisecond

#define TIMER0_RELOAD_HIGH       AUX2  // Reload value for Timer0 high byte
#define TIMER0_RELOAD_LOW        AUX2  // Reload value for Timer0 low byte

SBIT (LED, SFR_P1, 3);                 // LED='1' means ON
SBIT (SIGNAL, SFR_P1, 7);              // SIGNAL to be used also by Timer0


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

void PCA0_Init (void);
void Oscillator_Init (void);
void Port_Init (void);
void Timer0_Init(void);

//-----------------------------------------------------------------------------
// main() Routine
//-----------------------------------------------------------------------------
void main (void)
{
   PCA0MD &= ~0x40;                    // Disable watchdog timer

   Oscillator_Init ();
   Timer0_Init ();                     // Initialize the Timer0
   Port_Init ();                       // Init Ports
   EA = 1;                             // Enable global interrupts

   while (1);                          // Loop forever

}

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

//-----------------------------------------------------------------------------
// Oscillator_Init
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters   : None
//
// This function initializes the system clock to use the internal oscillator
// at 24.5/8 MHz.
//
//-----------------------------------------------------------------------------
void Oscillator_Init (void)
{
   OSCICN = 0x84;                      // Set the internal oscillator to
                                       // 24.5/8 MHz
}

//-----------------------------------------------------------------------------
// Port_Init
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters   : None
//
// This function configures the crossbar and GPIO ports.
//
// Pinout:
//
//    P1.3 -> LED (toggled by TL0)
//
//    P1.7 -> SIGNAL (toggled by TH0)
//
//    all other port pins unused
//
//-----------------------------------------------------------------------------
void Port_Init (void)
{
   P1MDOUT = 0x88;                     // Set LED and SIGNAL to
                                       // be used as push-pull

   XBR1 = 0xC0;                        // Enable crossbar
}

//-----------------------------------------------------------------------------
// Timer0_Init
//-----------------------------------------------------------------------------
//
// Return Value : None
// Parameters   : None
//
// This function configures the Timer0 as two 8-bit timers, interrupt enabled.
// Using the internal osc. at 12MHz with a prescaler of 1:8 and reloading the
// TH0 register with TIMER0_RELOAD_HIGH and TL0 with TIMER0_RELOAD_HIGH.
//
// Note: The Timer0 uses a 1:48 prescaler.  If this setting changes, the
// TIMER_PRESCALER constant must also be changed.
//-----------------------------------------------------------------------------
void Timer0_Init(void)
{
   TH0 = TIMER0_RELOAD_HIGH;           // Init Timer0 High register
   TL0 = TIMER0_RELOAD_LOW;            // Init Timer0 Low register

   TMOD = 0x03;                        // Timer0 in two 8-bit mode
   CKCON = 0x02;                       // Timer0 uses a 1:48 prescaler
   ET0 = 1;                            // Timer0 interrupt enabled
   ET1 = 1;                            // Timer1 interrupt enabled
   TCON = 0x50;                        // Timer0 and timer1 ON
}


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

//-----------------------------------------------------------------------------
// Timer0_ISR
//-----------------------------------------------------------------------------
//
// Here we process the Timer0 interrupt and toggle the LED
//
//-----------------------------------------------------------------------------
void Timer0_ISR (void) interrupt 1
{
   static unsigned int low_counter=0;  // Define counter variable

   TL0 = TIMER0_RELOAD_LOW;            // Reinit Timer0 Low register
   if((low_counter++) == LED_TOGGLE_RATE)
   {
      low_counter = 0;                 // Reset interrupt counter
      LED = ~LED;                      // Toggle the LED
   }
}

//-----------------------------------------------------------------------------
// Timer1_ISR
//-----------------------------------------------------------------------------
//
// Here we process the Timer1 interrupt and toggle the SIGNAL I/O
// Note: In this mode the Timer0 is effectively using the Timer1 interrupt
// vector. For more info check the Timers chapter of the datasheet.
//-----------------------------------------------------------------------------
void Timer1_ISR (void) interrupt 3
{
   static unsigned int high_counter=0;

   TH0 = TIMER0_RELOAD_HIGH;           // Reinit Timer0 High register
   if((high_counter++) == SIGNAL_TOGGLE_RATE)
   {
      high_counter = 0;                // Reset interrupt counter
      SIGNAL = ~SIGNAL;                // Toggle Signal
   }
}

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