组装-如何设置中断频率 [英] Assembly - how to set frequency of interrupt

问题描述

使用程序集和AVR微控制器，我想编写一个程序，该程序以一定的频率(例如10 Hz)引起中断处理. 首先，我设置堆栈和计时器:

Using assembly and AVR Microcontroller I want to write program which causes the interrupt handling with a certain frequency, eg 10 Hz. first I set the stack and the timer:

.cseg

.org jmp restart;

.org 0x002E tjmp timer_fun


restart:
cli
ldi R16, HIGH(RAMEND)
out SPH, R16
ldi R16, LOW(RAMEND)
out SPL, R16
sei

ldi R17, 1<<CSOO
out TCCR0, R17
ldi R16, 1<<TOIE0
out TIMSK, R16

但是现在，我不知道如何设置此频率?

But now, I don't know how to set this frequency?

推荐答案

您可以通过计算触发的中断数来做到这一点.它取决于计时器的输入频率(我想通常与CPU频率相同).

You can do this by counting the number of interrupts triggered. It would depend on the input frequency for the timer (which I guess would typically be the same as the CPU frequency).

假设输入频率为16000000 Hz:

Let's say that the input frequency is 16000000 Hz:

从计数0(TCNT0设置为0)开始，并且预分频器为256(TCCR0设置为1<<CS02)，将导致计时器溢出16000000/256 == 62500 Hz.

Starting at a count of 0 (TCNT0 set to 0), and a prescaler of 256 (TCCR0 set to 1<<CS02) would cause a timer overflow at 16000000/256 == 62500 Hz.

您的计时器中断服务例程可以执行以下操作(我在这里使用C，但是您知道了)

Your timer interrupt service routine could then do something like this (I'm using C here, but you get the idea):

counter++;
if (counter == 6250) {
    // We should end up in here approximately 10 times/second
    counter = 0;
}

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