AVR-Chat

dear friends
i have written following programm
for delay why it is not working.
my clock speed is 4Mz and and want use it for LCD display delays

void waitMS(unsigned long ulMS)
{
CLI(); // disable all interrupts
ulTick = ulMS;
SEI(); // re-enable interrupts
while (ulTick>0);
}

void timer1_init(void)
{
TCCR1B = 0x00; //stop
TCNT1H = 0xC6; //setup
TCNT1L = 0x67;
OCR1AH = 0x39;
OCR1AL = 0x99;
OCR1BH = 0x39;
OCR1BL = 0x99;
ICR1H = 0x39;
ICR1L = 0x99;
TCCR1A = 0x00;
TCCR1B = 0x01; //start Timer
}

// TIMER1 has overflowed
#pragma interrupt_handler timer1_ovf_isr:10
void timer1_ovf_isr(void)
{
TCNT1H = 0xC6;
TCNT1L = 0x67;
if (ulTick > 0)
ulTick--;
}


On Fri, 24 Feb 2006 Zack Widup wrote :
>There should be enough data in the AVR data sheet to do that. And there
>should be examples at the AVRFreaks website, if not at the Atmel website
>itself, on doing that.
>Zack
>On Fri, 24 Feb 2006, kishorbande wrote:
>> dear freinds
>>
>> i am using this controller from last 6 months.
>> i am want to generate accurate 1 sec and 1milisec delay routines.
>> i am using imagecraft c cross compiler.
>> please help me.
>>
>> regards
>> kishor
>>
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On Feb 24, 2006, at 9:46 PM, kishor lalu bande wrote:

> i have written following programm
> for delay why it is not working.
> my clock speed is 4Mz and and want use it for LCD display delays
>
> void waitMS(unsigned long ulMS)
> {
>     CLI();          // disable all interrupts
>     ulTick = ulMS;
>     SEI();          // re-enable interrupts
>     while (ulTick>0);
> }

You don't show the definition of ulTick. It must be volatile.

As for timing I/O to LCD's, don't. Poll the LCD for its busy bit,  
while using a timer (such as your ulTick) to prevent an infinite loop  
if the LCD does not respond.

--
David Kelly N4HHE, dkelly@HiWAAY.net
========================================================================
Whom computers would destroy, they must first drive mad.