DISABLE命令是禁止中断的作用.
看来你可能还没有真正理解和掌握T/C的工作原理. 如果T/C的使用在整个系统中不改变的话,T/C的设置应该放在主程序开始的初始化代码中.
下面是BASCOM-AVR中的例子,你可以参考.
'-----------------------------------------------------------------------------------------
'name : timer0.bas
'copyright : (c) 1995-2005, MCS Electronics
'purpose : shows how to use TIMER0 related statements
'micro : Mega48
'suited for demo : yes
'commercial addon needed: no
'-----------------------------------------------------------------------------------------
$regfile = "2313def.dat" ' specify the used micro
$crystal = 8000000 ' used crystal frequency
$baud = 19200 ' use baud rate
$hwstack = 32 ' default use 32 for the hardware stack
$swstack = 10 ' default use 10 for the SW stack
$framesize = 40 ' default use 40 for the frame space
'First you must configure the timer to operate as a counter or as a timer
'Lets configure it as a COUNTER now
'You must also specify if it will count on a rising or falling edge
Config Timer0 = Counter , Edge = Rising
'Config Timer0 = Counter , Edge = falling
'unremark the line aboven to use timer0 to count on falling edge
'To get/set the value from the timer access the timer/counter register
'lets reset it to 0
Tcnt0 = 0
Do
Print Tcnt0
Loop Until Tcnt0 >= 10
'when 10 pulses are count the loop is exited
'or use the special variable TIMER0
Timer0 = 0
'Now configire it as a TIMER
'The TIMER can have the systemclock as an input or the systemclock divided
'by 8,64,256 or 1024
'The prescale parameter excepts 1,8,64,256 or 1024
Config Timer0 = Timer , Prescale = 1
'The TIMER is started now automaticly
'You can STOP the timer with the following statement :
Stop Timer0
'Now the timer is stopped
'To START it again in the last configured mode, use :
Start Timer0
'Again you can access the value with the tcnt0 register
Print Tcnt0
'or
Print Timer0
'when the timer overflows, a flag named TOV0 in register TIFR is set
'You can use this to execute an ISR
'To reset the flag manual in non ISR mode you must write a 1 to the bit position
'in TIFR:
Set Tifr.1
'The following code shows how to use the TIMER0 in interrupt mode
'The code is block remarked with '(en ')
'(
'Configute the timer to use the clock divided by 1024
Config Timer0 = Timer , Prescale = 1024
'Define the ISR handler
On Ovf0 Tim0_isr
'you may also use TIMER0 for OVF0, it is the same
Enable Timer0 ' enable the timer interrupt
Enable Interrupts 'allow interrupts to occur
Do
'your program goes here
Loop
'the following code is executed when the timer rolls over
Tim0_isr:
Print "*";
Return
')
End
页:
[1]