/*kernel calls attach the interrupt function handler to the hardware interrupt specified by intr(i.e irq) */
// InterruptAttach() : Attach an interrupt handler to an interrupt source
// interrupt source is handler1 for this example
void ConfigureISR(void) //void *ISR (void *arg)
{
/* the software must tell the OS that it wishes to associate the ISR with a particular source of //interrupts. On x86 platforms, there are generally 16 hardware Interrupt Request lines (IRQs) */
StartInterruptTime = GetTimeStamp(); //startTime of the interrupt
volatile int irq = 7; //0 : A clock that runs at the resolution set by ClockPeriod()
ThreadCtl (_NTO_TCTL_IO, NULL); // enables the hardware interrupt
id1 = InterruptAttach(irq, &ISR, NULL, 0, 0); // ISR is the interrupt service routine
//sleep(20);
}
int main ()
{
ConfigureISR();
return 1;
}
I created a interrupt handler on the server side to handle the interrupt from the client side. but the above code is breaking at the interrupt attach function call. could someone tell me why is it breaking ?? Is it the right way to handle interrupts in user application.
Related
I have code written by someone else (for a dsPIC33FJ128MC706A) - which initializes UART1 & PWMs and uses a busy wait in the U1Rx interrupt to get 14 bytes, and timer1 interrupts to update PWM registers if new data arrives (debugged - it enters the _U1RXInterrupt when data is sent)
I tried modifying it to use DMA instead of busy wait. I changed nothing in the initialization, but called the following function after initialization of UART:
unsigned char received_data1 [0x0f] __attribute__((space(dma)));
unsigned char received_data2 [0x0f] __attribute__((space(dma)));
void dma_init(void)
{
DMA0REQ = 0x000b; // IRQSEL = 0b0001011 (UART1RX))
DMA0PAD = (volatile unsigned int) &U1RXREG;
DMA0STA = __builtin_dmaoffset(received_data1);
DMA0STB = __builtin_dmaoffset(received_data2);
DMA0CNT = 0xe;//15 bytes in
DMA0CON = 0x0002; //continuous ping-pong + post-increment
IFS0bits.DMA0IF = 0;
IEC0bits.DMA0IE = 1;
DMA0CONbits.CHEN = 1;
}
This is based on example 22-10 in the FRM with a few slight changes (UART1 receiver instead of UART2). I can't seem to find other examples that don't use library functions (which I didn't even know existed up until I came across those examples).
(Also, to be consistent with the code I got, I put in _ISR after void instead of making interrupt an attribute, but that didn't change anything)
In the example, there was no interrupt for the UART1 receiver - but according to the FRM, it should be enabled. Made sense to me that I don't need to clear the interrupt flag myself (it would kind-of defeat the purpose of DMA if I needed to use the CPU for it).
And yet, when I send data, the breakpoint on DMA0Interrupt doesn't trigger, but the one on the default interrupt does, and I have PWMIF=1 and U1RXIF=1. I also tried commenting out the default ISR and adding a _U1ErrInterrupt even though examining the flags I didn't notice any error flags being raised, just the normal U1RXIF.
I don't understand why this would happen. I haven't changed the PWM code at all, and the PWM flag isn't raised in the original code when I place a breakpoint in the _U1RxInterrupt. I don't even understand how a DMA set-up could cause a PWM error.
The U1RXIF flag seems to be telling me the DMA didn't handle the incoming byte (I assume it's the DMA that clears the flag), which once again relates to the question "what did I do wrong in this DMA setup"
UART initialization code:
in a general initialization function (called by main())
TRISFbits.TRISF2 = 1; /* U1RX */
TRISFbits.TRISF3 = 0; /* U2TX */
also called by main:
void UART1_init_USB (void)
{
/* Fcy 7.3728 MHZ */
U1MODE = 0x8400; /* U1ATX Transmit status and control register */
U1STA = 0x2040; /* Receve status and control register Transmit disabled*/
U1BRG = 0x000f; /* Baund rate control register 115200 bps */
IPC2bits.U1RXIP = 3; /* Receiver Interrupt Priority bits */
IEC0bits.U1RXIE = 1; /* Enable RS232 interrupts */
IFS0bits.U1RXIF = 0;
}
(comments by original code author)
I've been trying to configure & run hardware timer over SAML21 MCU to generate a 100ms delay i.e. ISR is supposed to hit at every 100ms. But it is observed that after starting the timer ISR is hitting at every 10us and changing the Prescaler & Compare register values isn't creating any difference in the 10us interval. Please review my code and let me know where I'm doing wrong.
I'm trying to configure Timer1(TC1) in 16bit mode, using GCLK_GENERATOR_1 as its clock source running at 8MHz frequency(CPU Main Clock:16MHz). The timer is expected to cause overflow interrupt every 100ms.
TcCount16 *tc_hw1 = NULL; /* Pointer to TC1 hardware registers Initilized later */
void init_timer1(void)
{
struct tc_module tc_inst1;
struct tc_config conf_tc1;
tc_get_config_defaults(&conf_tc1);
conf_tc1.clock_source = GCLK_GENERATOR_1;
conf_tc1.clock_prescaler = TC_CLOCK_PRESCALER_DIV64; /* 8MHz/64 = 125KHz*/
conf_tc1.reload_action = TC_RELOAD_ACTION_GCLK;
conf_tc1.counter_size = TC_COUNTER_SIZE_16BIT;
conf_tc1.count_direction = TC_COUNT_DIRECTION_UP;
conf_tc1.counter_16_bit.value = 0x0000;
/** Rest of the settings are used as defaults **/
while (tc_init(&tc_inst1, TC1, &conf_tc1) != STATUS_OK){
}
tc_set_top_value(&tc_inst1, 12500); /* Set counter compare top value */
/* Enable interrupt & Set Priority */
tc_hw1 = &(tc_inst1.hw->COUNT16); /* Initialize pointer to TC1 hardware register */
tc_hw1->INTENSET.reg |= TC_INTFLAG_OVF; /* Enable Overflow Interrupt */
NVIC_SetPriority(TC1_IRQn, 2);
NVIC_EnableIRQ(TC1_IRQn);
tc_enable(&tc_inst1); /*Start The TIMER*/
}
void TC1_Handler(void)
{
if((tc_hw1->INTFLAG.reg) & (TC_INTFLAG_OVF))
{
port_pin_toggle_output_level(PIN_PB03);
}
system_interrupt_clear_pending(SYSTEM_INTERRUPT_MODULE_TC1);
}
Debugger Information: I can see that the timer register is configured correctly but the COUNT register is not incrementing itself every time I pause to capture the debug info it shows only 0x0000 values.
Please help. Thanks!
I resolved the issue actually it's kind of mandatory to clear the timer OVF bit in the INTFLAG register. So the interrupt handler should've been like this:
void TC1_Handler(void)
{
if((tc_hw1->INTFLAG.reg) & (TC_INTFLAG_OVF))
{
tc_hw1->INTFLAG.reg = TC_INTFLAG_OVF; /*Clears the flag by writing 1 to it*/
port_pin_toggle_output_level(PIN_PB03);
}
system_interrupt_clear_pending(SYSTEM_INTERRUPT_MODULE_TC1); /*Not necessarily needed*/
}
I am trying to implement the following pseudocode on a cortex-m3 controller, (STM32L151 in particular)
void SysTick_Handler() {
do_high_priority_periodic_tasks(); // not to be interrupted
lower_interrupt_priority();
do_low_priority_periodic_tasks(); // these may be interrupted
}
In other words, run the first part with priority level 0, then somehow lower the current interrupt priority to 15, so that the rest could be preempted by other hardware interrupts.
One idea is to move do_low_priority_periodic_tasks(); into a separate interrupt handler, and invoke this handler through NVIC_SetPendingIRQ() which sets a pending bit in the NVIC->ISPR[] register. This way, the other interrupt would immediately follow SysTick, unless there is anything with priority between 0 and 14 pending.
#define LOWPRIO_IRQn 55
void IRQ55_Handler() {
do_low_priority_periodic_tasks(); // these may be interrupted
}
void SysTick_Handler() {
do_high_priority_periodic_tasks(); // not to be interrupted
NVIC_SetPendingIRQ(LOWPRIO_IRQ);
}
void main() {
HAL_Init();
HAL_NVIC_SetPriority(SysTick_IRQn, 0, 0);
HAL_NVIC_SetPriority(LOWPRIO_IRQn, 15, 0);
HAL_NVIC_EnableIRQ(LOWPRIO_IRQn);
while(1) {
/* main loop */
}
}
I've picked IRQ 55 because it's not occupied on my controller, it would be the AES interrupt handler on a STM32L162, but I'm a bit worried there. Should I pick a different IRQ instead, perhaps an unused DMA channel interrupt? Is it safe to use interrupts 57-67, which are defined in the Cortex-M3 core, but not on the STM32L series? Is there any better way to do it?
Is it safe to use interrupts 57-67, which are defined in the Cortex-M3 core, but not on the STM32L series?
No. Your NVIC may not actually implement them.
But the PendSV is exactly made for this task:
void SysTick_Handler() {
do_high_priority_periodic_tasks(); // not to be interrupted
// Set the PENDSVSET to trigger a PendSV exception
SCB->ICSR |= SCB_ICSR_PENDSVSET_Msk;
}
void PendSV_Handler() {
do_low_priority_periodic_tasks(); // these may be interrupted
}
See also this answer about PendSV.
client- server communication - client is sender and server is receiver. when the server receives the data on the ethernet interface(UDP) the kernel in the server is triggered. I am using QNX on the server side. server(i.e embedded pc target) is handling interrupts to trigger the embedded pc target (conatining QNX) to gain the attention to execute the newly arrived data.
const struct sigevent *handler1(void *area, int id1)
{
volatile double KernelStartExecutionTime;
struct sigevent *event = (struct sigevent *)area;
KernelStartExecutionTime = GetTimeStamp(); // calculating the time when the kernel //starts executing
measurements[18] = KernelStartExecutionTime ;
//return (NULL);
return event;
}
/*kernel calls attach the interrupt function handler to the hardware interrupt specified by intr(i.e irq) */
// InterruptAttach() : Attach an interrupt handler to an interrupt source
// interrupt source is handler1 for this example
void ISR(void) //void *ISR (void *arg)
{
/* the software must tell the OS that it wishes to associate the ISR with a particular source of interrupts.
* On x86 platforms, there are generally 16 hardware Interrupt Request lines (IRQs) */
volatile int irq = 0; //0 : A clock that runs at the resolution set by ClockPeriod()
struct sigevent event;
event.sigev_notify = SIGEV_INTR;
ThreadCtl (_NTO_TCTL_IO, NULL); // enables the hardware interrupt
id1 = InterruptAttach(irq, &handler1, &event, sizeof(event), 0); // handler1 is the ISR
while(1)
{
InterruptWait( 0, NULL );
InterruptUnmask(irq, id1);
}
InterruptDetach( id1);
}
int main(int argc, char *argv[])
{
ISR(); //function call for ISR
// pthread_create (NULL, NULL, ISR, NULL);
return 0;
}
question:
Should I create a new thread for handling interrupts within the main??
first code:
//------------------------------------------------------------------------------
/// Interrupt handlers for TC interrupts. Toggles the state of LEDs
//------------------------------------------------------------------------------
char token = 0;
void TC0_IrqHandler(void) {
volatile unsigned int dummy;
dummy = AT91C_BASE_TC0->TC_SR;
if(token == 1) {
PIO_Clear(&leds[0]);
PIO_Set(&leds[1]);
token = 0;
}
else {
PIO_Set(&leds[0]);
PIO_Clear(&leds[1]);
token = 1;
}
}
//------------------------------------------------------------------------------
/// Configure Timer Counter 0 to generate an interrupt every 250ms.
//------------------------------------------------------------------------------
void ConfigureTc(void) {
unsigned int div;
unsigned int tcclks;
AT91C_BASE_PMC->PMC_PCER = 1 << AT91C_ID_TC0; // Enable peripheral clock
TC_FindMckDivisor(1, BOARD_MCK, &div, &tcclks); // Configure TC for a 4Hz frequency and trigger on RC compare
TC_Configure(AT91C_BASE_TC0, tcclks | AT91C_TC_CPCTRG);
AT91C_BASE_TC0->TC_RC = (BOARD_MCK / div) / 1; // timerFreq / desiredFreq
IRQ_ConfigureIT(AT91C_ID_TC0, 0, TC0_IrqHandler); // Configure and enable interrupt on RC compare
AT91C_BASE_TC0->TC_IER = AT91C_TC_CPCS;
IRQ_EnableIT(AT91C_ID_TC0);
printf(" -- timer has started \n\r");
TC_Start(AT91C_BASE_TC0);
}
it's just interrupt timer and it's event (handler) but when I run some
while(1) {
// action
after ConfigureTc() it both cycle and interrupt timer are freezes... Why could that be? Should I add another timer and avoid while(1) ?
while(1) {
printf("hello");
}
-- this breaks (freeze) loops (yes, if I don't use timer it works as it must)
I'll venture an actual answer here. IME, 99% of the time my boards 'go out' with no response on any input and no 'heartbeat' LED-flash from the low-priority 'blinky' thread, the CPU has flown off to a prefetch or data abort handler. These handlers are entered by interrupt and most library-defined default handlers do not re-enable interrupts, so stuffing the entire system. Often, they're just endless loops and, with interrupts disabled, that's the end of the story:(
I have changed my default handlers to output suitable 'CRITICAL ERROR' messages to the UART, (by polling it - the OS/interrupts are stuft!).