在Atmega16中实现Atmega8的定时器代码
在Atmega16中实现Atmega8的定时器代码
提问于 2012-12-20 06:23:32
这段代码是为取自clapper circuit using Atmega8的Atmega8编写的。任何人都可以转换这段代码的Atmega16和一些解释。因为我正在尝试为Atmega16实现同样的功能，并且在计时器部分遇到了一些麻烦。
#define BURST_TIME 70
#define READY_TIME 150
#define TIME_OUT 300
void timer_init()
{
TIFR |= (1<<TOV0);
//set interrupt on overflow
TIMSK |= (1<<TOIE0);
TCNT0 = 223;
}
ISR (TIMER0_OVF_vect)
{
TCNT0 = 223;
timer++;
if (timer == BURST_TIME)
{
burst = 1;
ready = 0;
} else if (timer == READY_TIME)
{
burst = 0;
ready = 1;
} else if (timer == TIME_OUT)
{
timer = 0;
burst = 0;
ready = 0;
first = 0;
stop_timer();
}
}
void start_timer()
{
TCCR0 |= (1<<CS02);
}
void stop_timer()
{
TCCR0 &= ~(1<<CS02);
}回答 1
Stack Overflow用户
发布于 2013-01-05 10:49:11
尝试使用Atmel的芯片数据表，并比较定时器寄存器，您将找到所需的所有内容
Atmega8：http://www.atmel.com/images/doc2486.pdf有用:寄存器摘要页280
Atmega16：http://www.atmel.com/Images/doc2466.pdf有用:寄存器摘要页331
你想使用定时器0，那是一个8位的定时器(在Atmega16上是第71页)
现在让我们试着分析一下代码
TIFR |= (1<<TOV0); // TIFR Thats the Timer/Counter0 Interrupt Flag Register
// TOV0: Timer/Counter0 Overflow Flag
// The bit TOV0 is set when an overflow occurs in Timer/Counter0.
// Datasheet page: 86
TIMSK |= (1<<TOIE0); // Timer/Counter Interrupt Mask Register
// TOIE0: Timer/Counter0 Overflow Interrupt Enable
// When the TOIE0 bit is written to one, and the I-bit in the `status Register is set, the
// Timer/Counter0 Overflow interrupt is enabled
TCNT0 = 223; // TCNT0: 0 to 255 or 0x00 to 0xFF
// with each clock it increases by 1
// when the register hits 255, a Timer-Overflow is triggerd (ISR...)
// The flag can be queried or used to trigger an interrupt.
// Datasheet Page 85
TCCR0 |= (1<<CS02); // TCCR0: Timer/Counter Control Register
// CS02: Bit 2:0 – CS02:0: Clock Select
// This means that your running the Timer with a
// Prescaler of 256 (CPU frequency / 256)
// This line starts the Timer!
// Datasheet Page: 85
ISR (TIMER0_OVF_vect) // will be executed when a overflow is triggerd
{
// Do something
// Keep the execution time short in this section
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/13962256
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