interrupt-handling | 易学教程

Should my interrupt handler disable interrupts or does the ARM processor do it automatically?

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问题 Our group is using a custom driver to interface four MAX3107 UARTs on a shared I2C bus. The interrupts of the four MAX3107's are connected (i.e. shared interrupt via logic or'ing)) to a GPIO pin on the ARM9 processor (LPC3180 module). When one or more of these devices interrupt, they pull the GPIO line, which is configured as a level-sensitive interrupt, low. My question concerns the need, or not, to disable the specific interrupt line in the handler code. (I should add that we are running

Java Hardware Interrupt Handling

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问题 I would like to know if it is possible to automatically invoke a Java method when a hardware interrupt is raised. 回答1: There may be an alternative. I'm doing something similar: In an application I monitor 4 mice for clicks. Those clicks generate interrupts but I'm happy enough not to deal with them directly from Java. Under Linux, it turns out there are device files ( /dev/input/mouse# ) that spew a bunch of characters when something happens with the mouse. I have a Thread for each one with a

interrupt() not working as expected (how does interrupt work?)

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问题 I want to interrupt a thread, but invoking interrupt() doesn't seem to work. Below is the sample code: public class BasicThreadrRunner { public static void main(String[] args) { Thread t1 = new Thread(new Basic(), "thread1"); t1.start(); Thread t3 = new Thread(new Basic(), "thread3"); Thread t4 = new Thread(new Basic(), "thread4"); t3.start(); t1.interrupt(); t4.start(); } } class Basic implements Runnable{ public void run(){ while(true) { System.out.println(Thread.currentThread().getName());

STM32F207 I2C test failing

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I am learning embedded development on the STM3220G-EVAL board with the STM32F207 microcontroller. I have tried to test the I2C interface by interfacing the two I2C2 and I2C3 modules on the same chip and sending/receiving a character. Here is the code I have currently written (using mdk-arm 5): #include <stm32f2xx.h> volatile uint8_t data = 'a', recv = 'x'; void i2c_init(void); void I2C2_EV_IRQHandler(void) { volatile uint16_t stat, dummy; stat = I2C2->SR1; switch(stat) { // SB set; read SR1 and write slave address in DR to clear case 0x01: dummy = I2C2->SR1; // Send address of slave I2C2->DR =

What happens to software interrupts in the pipeline?

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After reading this: When an interrupt occurs, what happens to instructions in the pipeline? There is not much information on what happens to software interrupts but we do learn the following: Conversely, exceptions, things like page faults, mark the instruction affected. When that instruction is about to commit, at that point all later instructions after the exception are flushed, and instruction fetch is redirected. I was wondering what would happen to software interrupts (INT 0xX) in the pipeline, firstly, when are they detected? Are they detected at the predecode stage perhaps? In the

ARM Interrupt Handling in QEMU

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I'm trying to understand how QEMU handles interrupts for ARM processors. I have a bare metal binary blob (ie, not linux -- just some assembly code) which was built for a ARM1176. When run in QEMU, during initialisation the code in the binary blob sets bit 13 of the CPSR indicating that the interrupt vector table is located at 0xFFFF0000 . Hooking up GDB and dumping the instructions at that address, I can indeed see the corresponding interrupt vector table. On an IRQ, it jumps to 0xFFFF0018 , which just does a jump to 0xFFFF00070 , which has the code for the first irq_handler, and ultimately

difference between software interrupt and signal

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问题 "Software interrupts are delivered using signals" Is this always true, if not then a) what is the difference between two If yes, is there some other mechanism, by which software interrupts are raised, other than delivering signals. 回答1: The author of that quote appears to be using "Software interrupt" in a very general sense (i.e. "anything that causes a program to diverge from it's usual flow of operation and does not originate in hardware" ) and "signals" in the sense of a particular

How to give highest priority to ethernet interrupt in linux

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问题 I listed all interrupts with this: cat /proc/interruts it gives this: CPU0 CPU1 CPU2 CPU3 0: 126 0 0 0 IO-APIC-edge timer 1: 941 0 0 0 IO-APIC-edge keyboard ... (etc.) 19: 941 0 0 0 IO-APIC-fasteoi eth0 ... (etc.) Does the first column in this table give priority level of interrupts? I just want to learn priority levels, because I want to increase my NIC's interrupt priority level for better network performance. I think, first two interrupts cannot be changed (I guess due to intel x86

What happens to preempted interrupt handler?

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问题 I could not find a proper answer for the following questions even in some well written kernel books: They are saying that an ISR can't sleep because its not possible to reschedule an ISR as it is not connected with any process , so what happens when a higher priority interrupt preempt the executing one? the interrupted ISR will not rescheduled(execute) again ? if yes how & who will do that work? many time we will disable interrupt (eg: 1.In critical region 2. When a fast interrupt is

How can I add a user interrupt to an infinite loop?

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问题 I have a ruby script below which infinitely prints numbers from 1 onward. How can I make the script stop its infinite execution through an interrupt in the terminal like 'Ctrl+C' or key 'q'? a = 0 while( a ) puts a a += 1 # the code should quit if an interrupt of a character is given end Through every iteration, no user input should be asked. 回答1: I think you will have to check the exit condition in a separate thread: # check for exit condition Thread.new do loop do exit if gets.chomp == 'q'