请教关于C8051F单片机看门狗程序问题
时间：10-02
整理：3721RD
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我想在我的程序中加入看门狗程序，网上找了一个，看不懂，也不知道哪句有用，求大神帮忙分析，小弟不胜感激！
//-----------------------------------------------------------------------------
// F41x_Watchdog.c
//-----------------------------------------------------------------------------
// Copyright 2006 Silicon Laboratories, Inc.
// http://www.silabs.com
//
// Program Description:
//
// This program helps the user to learn about operating the Watch Dog Timer.
// The WDT is used to generate resets if the times between writes to the WDT
// update register (PCA0CPH5) exceed a specified limit. The WDT can be disabled
// and enabled in the software as needed. When enabled the PCA Module 5 acts as
// the WDT. This program resets the MCU when P1.4 switch is pressed for 3
// seconds. Also upon reset the LED blinks approximately five times faster
// when compared to before. The reset is caused due to a WDT overflow and can
// be confirmed by checking the value of the RSTSRC register where bit 3 is
// set to indicate a reset caused by WDT.
//
// How to Test:
// 1) Compile and download code to a 'F410 device
// 2) Place shorting blocks on P2.1/D3 and P1.4/SW2 pin pairs on jumper J5.
// 3) Run the code:
// - The test will blink the LED at a rate of 8Hz until the switch SW2
// (P0.7) is pressed for at least 3 secs.
// - Once the the switch is pressed and held for a long enough time,
// it will prevent the WDT from being touched and the WDT will
// cause a reset.
// - Upon reset the code checks for a WDT reset and blinks the LED five
// times faster than before to indicate the same.
//
//
// FID: 41X000031
// Target: C8051F410
// Tool chain: Keil C51 7.50 / Keil EVAL C51
// Command Line: None
//
// Release 1.0
// -Initial Revision SM
// -20 JULY 2006
//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------
#include <c8051f410.h> // SFR declarations
//-----------------------------------------------------------------------------
// 16-bit SFR Definitions for 'F41x
//-----------------------------------------------------------------------------
sfr16 TMR2RL = 0xca; // Timer2 reload value
sfr16 TMR2 = 0xcc; // Timer2 counter
//-----------------------------------------------------------------------------
// Global CONSTANTS
//-----------------------------------------------------------------------------
#define SYSCLK 24500000 / 8 // SYSCLK frequency in Hz
sbit LED = P2^1; // LED='1' means ON
sbit SW2 = P1^4; // SW2='0' means switch pressed
//-----------------------------------------------------------------------------
// Function PROTOTYPES
//-----------------------------------------------------------------------------
void OSCILLATOR_Init (void);
void PORT_Init (void);
void PCA_Init (void);
void Timer2_Init (int counts);
void Timer2_ISR (void);
//-----------------------------------------------------------------------------
// main() Routine
//-----------------------------------------------------------------------------
//
// The MAIN routine performs all the intialization, and then loops until the
// switch is pressed. When SW2 (P1.4) is pressed the code checks the RSTSRC
// register to make sure if the last reset is because of WDT.
//-----------------------------------------------------------------------------
void main (void)
{
PCA0MD &= ~0x40; // WDTE = 0 (clear watchdog timer
// enable)
OSCILLATOR_Init (); // Initialize system clock to 24.5/8 MHz
PCA_Init(); // Intialize the PCA
PORT_Init(); // Initialize crossbar and GPIO
if ((RSTSRC & 0x02) == 0x00) // First check the PORSF bit. if PORSF
{ // is set, all other RSTSRC flags are
// invalid
// Check if the last reset was due to the Watch Dog Timer
if (RSTSRC == 0x08)
{
// Make LED blink at 12Hz
Timer2_Init (SYSCLK / 12 / 6);
// Enable global interrupts
EA = 1;
while(1); // wait forever
}
else
{
// Init Timer2 to generate interrupts at a 4Hz rate.
Timer2_Init (SYSCLK / 12 / 4);
}
}
// Calculate Watchdog Timer Timeout
// Offset calculated in PCA clocks
// Offset = ( 256 x PCA0CPL5 ) + 256 - PCA0L
// = ( 256 x 255(0xFF)) + 256 - 0
// Time = Offset * (12/SYSCLK)
// = ~255 ms ( PCA uses SYSCLK/12 as its clock source)
PCA0MD &= ~0x40; // WDTE = 0 (clear watchdog timer
// enable)
PCA0L = 0x00; // Set lower byte of PCA counter to 0
PCA0H = 0x00; // Set higher byte of PCA counter to 0
PCA0CPL5 = 0xFF; // Write offset for the WDT
PCA0MD |= 0x40; // Enable the WDT
EA = 1; // Enable global interrupts
//--------------------------------------------------------------------------
// Main Application Loop/Task Scheduler
//--------------------------------------------------------------------------
while (1)
{
//----------------------------------------------------------------------
// Task #1 - Check Port I/O
//----------------------------------------------------------------------
while(！SW2); // Force the MCU to stay in this task as
// long as SW2 is pressed. This task
// must finish before the watchdog timer
// timeout expires.
//-----------------------------------------------------------------------
// Task #2 - Reset Watchdog Timer
//-----------------------------------------------------------------------
PCA0CPH5 = 0x00; // Write a 'dummy' value to the PCA0CPH5
// register to reset the watchdog timer
// timeout. If a delay longer than the
// watchdog timer delay occurs between
// successive writes to this register,
// the device will be reset by the watch
// dog timer.
}
}
//-----------------------------------------------------------------------------
// Initialization Subroutines
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// OSCILLATOR_Init
//-----------------------------------------------------------------------------
// Return Value : None
// Parameters : None
// 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 OSCILLATOR_Init (void)
{
OSCICN = 0x84; // Configure internal oscillator
RSTSRC = 0x04; // Enable missing clock detector
}
//-----------------------------------------------------------------------------
// PCA_Init
//-----------------------------------------------------------------------------
// Return Value : None
// Parameters : None
// This routine initializes the PCA to use the SYSCLK / 12
// as its clock source. It also sets the offset value by writing to PCA0CPL2.
//-----------------------------------------------------------------------------
void PCA_Init()
{
PCA0CN = 0x40; // PCA counter enable
PCA0MD &= ~0x40 ; // Watchdog timer disabled-clearing bit 6
PCA0MD &= 0xF1; // Timebase selected - System clock / 12
PCA0CPL5 = 0xFF; // Offset value
}
//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
// Return Value : None
// Parameters : None
//
// This function configures the Crossbar and GPIO ports.
// P2.1 digital push-pull LED
//-----------------------------------------------------------------------------
void PORT_Init (void)
{
XBR0 = 0x00; // No digital peripherals selected
XBR1 = 0x40; // Enable crossbar and weak pull-ups
P2MDOUT |= 0x02; // Enable LED as a push-pull output
}
//-----------------------------------------------------------------------------
// Timer2_Init
//-----------------------------------------------------------------------------
// Return Value : None
// Parameters :
// 1) int counts - calculated Timer overflow rate
// range is positive range of integer: 0 to 32767
//
// 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 = 0x30; // Timer2 clocked based on SYSCLK
TMR2RL = -counts; // Init reload values
TMR2 = 0xffff; // Set to reload immediately
ET2 = 1; // Enable Timer2 interrupts
TR2 = 1; // Start Timer2
}
//-----------------------------------------------------------------------------
// Interrupt Service Routines
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// Timer2_ISR
//-----------------------------------------------------------------------------
// This routine changes the state of the LED whenever Timer2 overflows.
//-----------------------------------------------------------------------------
void Timer2_ISR (void) interrupt 5
{
TF2H = 0; // Clear Timer2 interrupt flag
LED = ~LED; // Change state of LED
}
//-----------------------------------------------------------------------------
// End Of File
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// F41x_Watchdog.c
//-----------------------------------------------------------------------------
// Copyright 2006 Silicon Laboratories, Inc.
// http://www.silabs.com
//
// Program Description:
//
// This program helps the user to learn about operating the Watch Dog Timer.
// The WDT is used to generate resets if the times between writes to the WDT
// update register (PCA0CPH5) exceed a specified limit. The WDT can be disabled
// and enabled in the software as needed. When enabled the PCA Module 5 acts as
// the WDT. This program resets the MCU when P1.4 switch is pressed for 3
// seconds. Also upon reset the LED blinks approximately five times faster
// when compared to before. The reset is caused due to a WDT overflow and can
// be confirmed by checking the value of the RSTSRC register where bit 3 is
// set to indicate a reset caused by WDT.
//
// How to Test:
// 1) Compile and download code to a 'F410 device
// 2) Place shorting blocks on P2.1/D3 and P1.4/SW2 pin pairs on jumper J5.
// 3) Run the code:
// - The test will blink the LED at a rate of 8Hz until the switch SW2
// (P0.7) is pressed for at least 3 secs.
// - Once the the switch is pressed and held for a long enough time,
// it will prevent the WDT from being touched and the WDT will
// cause a reset.
// - Upon reset the code checks for a WDT reset and blinks the LED five
// times faster than before to indicate the same.
//
//
// FID: 41X000031
// Target: C8051F410
// Tool chain: Keil C51 7.50 / Keil EVAL C51
// Command Line: None
//
// Release 1.0
// -Initial Revision SM
// -20 JULY 2006
//-----------------------------------------------------------------------------
// Includes
//-----------------------------------------------------------------------------
#include <c8051f410.h> // SFR declarations
//-----------------------------------------------------------------------------
// 16-bit SFR Definitions for 'F41x
//-----------------------------------------------------------------------------
sfr16 TMR2RL = 0xca; // Timer2 reload value
sfr16 TMR2 = 0xcc; // Timer2 counter
//-----------------------------------------------------------------------------
// Global CONSTANTS
//-----------------------------------------------------------------------------
#define SYSCLK 24500000 / 8 // SYSCLK frequency in Hz
sbit LED = P2^1; // LED='1' means ON
sbit SW2 = P1^4; // SW2='0' means switch pressed
//-----------------------------------------------------------------------------
// Function PROTOTYPES
//-----------------------------------------------------------------------------
void OSCILLATOR_Init (void);
void PORT_Init (void);
void PCA_Init (void);
void Timer2_Init (int counts);
void Timer2_ISR (void);
//-----------------------------------------------------------------------------
// main() Routine
//-----------------------------------------------------------------------------
//
// The MAIN routine performs all the intialization, and then loops until the
// switch is pressed. When SW2 (P1.4) is pressed the code checks the RSTSRC
// register to make sure if the last reset is because of WDT.
//-----------------------------------------------------------------------------
void main (void)
{
PCA0MD &= ~0x40; // WDTE = 0 (clear watchdog timer
// enable)
OSCILLATOR_Init (); // Initialize system clock to 24.5/8 MHz
PCA_Init(); // Intialize the PCA
PORT_Init(); // Initialize crossbar and GPIO
if ((RSTSRC & 0x02) == 0x00) // First check the PORSF bit. if PORSF
{ // is set, all other RSTSRC flags are
// invalid
// Check if the last reset was due to the Watch Dog Timer
if (RSTSRC == 0x08)
{
// Make LED blink at 12Hz
Timer2_Init (SYSCLK / 12 / 6);
// Enable global interrupts
EA = 1;
while(1); // wait forever
}
else
{
// Init Timer2 to generate interrupts at a 4Hz rate.
Timer2_Init (SYSCLK / 12 / 4);
}
}
// Calculate Watchdog Timer Timeout
// Offset calculated in PCA clocks
// Offset = ( 256 x PCA0CPL5 ) + 256 - PCA0L
// = ( 256 x 255(0xFF)) + 256 - 0
// Time = Offset * (12/SYSCLK)
// = ~255 ms ( PCA uses SYSCLK/12 as its clock source)
PCA0MD &= ~0x40; // WDTE = 0 (clear watchdog timer
// enable)
PCA0L = 0x00; // Set lower byte of PCA counter to 0
PCA0H = 0x00; // Set higher byte of PCA counter to 0
PCA0CPL5 = 0xFF; // Write offset for the WDT
PCA0MD |= 0x40; // Enable the WDT
EA = 1; // Enable global interrupts
//--------------------------------------------------------------------------
// Main Application Loop/Task Scheduler
//--------------------------------------------------------------------------
while (1)
{
//----------------------------------------------------------------------
// Task #1 - Check Port I/O
//----------------------------------------------------------------------
while(！SW2); // Force the MCU to stay in this task as
// long as SW2 is pressed. This task
// must finish before the watchdog timer
// timeout expires.
//-----------------------------------------------------------------------
// Task #2 - Reset Watchdog Timer
//-----------------------------------------------------------------------
PCA0CPH5 = 0x00; // Write a 'dummy' value to the PCA0CPH5
// register to reset the watchdog timer
// timeout. If a delay longer than the
// watchdog timer delay occurs between
// successive writes to this register,
// the device will be reset by the watch
// dog timer.
}
}
//-----------------------------------------------------------------------------
// Initialization Subroutines
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// OSCILLATOR_Init
//-----------------------------------------------------------------------------
// Return Value : None
// Parameters : None
// 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 OSCILLATOR_Init (void)
{
OSCICN = 0x84; // Configure internal oscillator
RSTSRC = 0x04; // Enable missing clock detector
}
//-----------------------------------------------------------------------------
// PCA_Init
//-----------------------------------------------------------------------------
// Return Value : None
// Parameters : None
// This routine initializes the PCA to use the SYSCLK / 12
// as its clock source. It also sets the offset value by writing to PCA0CPL2.
//-----------------------------------------------------------------------------
void PCA_Init()
{
PCA0CN = 0x40; // PCA counter enable
PCA0MD &= ~0x40 ; // Watchdog timer disabled-clearing bit 6
PCA0MD &= 0xF1; // Timebase selected - System clock / 12
PCA0CPL5 = 0xFF; // Offset value
}
//-----------------------------------------------------------------------------
// PORT_Init
//-----------------------------------------------------------------------------
// Return Value : None
// Parameters : None
//
// This function configures the Crossbar and GPIO ports.
// P2.1 digital push-pull LED
//-----------------------------------------------------------------------------
void PORT_Init (void)
{
XBR0 = 0x00; // No digital peripherals selected
XBR1 = 0x40; // Enable crossbar and weak pull-ups
P2MDOUT |= 0x02; // Enable LED as a push-pull output
}
//-----------------------------------------------------------------------------
// Timer2_Init
//-----------------------------------------------------------------------------
// Return Value : None
// Parameters :
// 1) int counts - calculated Timer overflow rate
// range is positive range of integer: 0 to 32767
//
// 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 = 0x30; // Timer2 clocked based on SYSCLK
TMR2RL = -counts; // Init reload values
TMR2 = 0xffff; // Set to reload immediately
ET2 = 1; // Enable Timer2 interrupts
TR2 = 1; // Start Timer2
}
//-----------------------------------------------------------------------------
// Interrupt Service Routines
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// Timer2_ISR
//-----------------------------------------------------------------------------
// This routine changes the state of the LED whenever Timer2 overflows.
//-----------------------------------------------------------------------------
void Timer2_ISR (void) interrupt 5
{
TF2H = 0; // Clear Timer2 interrupt flag
LED = ~LED; // Change state of LED
}
//-----------------------------------------------------------------------------
// End Of File
//-----------------------------------------------------------------------------
PCA0MD &= ~0x40; // WDTE = 0 (clear watchdog timer
// enable)
PCA0L = 0x00; // Set lower byte of PCA counter to 0
PCA0H = 0x00; // Set higher byte of PCA counter to 0
PCA0CPL5 = 0xFF; // Write offset for the WDT
PCA0MD |= 0x40; // Enable the WDT
这些是看门狗初始化
PCA0CPH5 = 0x00; // Write a 'dummy' value to the PCA0CPH5
这是喂狗