Re: [ECOS] Re: DSR question

[Gary Thomas <gthomas at ecoscentric dot com>]

On Sat, 2002-09-28 at 22:45, Tim Michals wrote:
> 
> All,
> 
> Problem:
> When the ISR is invoked several times the OS seems to lock up.  After
> investigation, the OS is running but the DSR loop is not being invoked.
> Used ARM ICE to verify ISR is still being called, but the DSR block stops
> being called. Why would this happen?  I'm sure it is some type of race
> condition.  But, with a simple DSR and ISR how could this happen?  Verified
> that the interrupt is not active.  The interrupt is MASKed off.  Turn the
> interrupt back on via the emulator, the isr is called.   Also, the ISR/DSR
> is being called a number of time, I'm doing a simulation by holding the
> interrupt pin high for several seconds.
> 
> Observations:
> The OS is running but any threads that are blocked on timers or any DSR
> calls, they are stopped.  Created a simple thread that just sends messages
> out the port, it never locks up.  Jut the threads blocked on timer, ie DSR.
> 
> Using eCOS version 2.0
> 
> Snippet for code:
> 
> static int
> lcd_panel_isr(cyg_vector_t vector, cyg_addrword_t data, HAL_SavedRegisters
> *regs)
> {
>     cyg_drv_interrupt_mask(CYGNUM_HAL_INTERRUPT_EINT2);
>     cyg_drv_interrupt_acknowledge(CYGNUM_HAL_INTERRUPT_EINT2);
>     return (CYG_ISR_CALL_DSR);  // Run the DSR
> }

You have to tell the interrupt code that your ISR was successful
in dealing with this, as well as schedule the DSR.  I always use:
    return (CYG_ISR_HANDLED|CYG_ISR_CALL_DSR);  // Run the DSR

> 
> // This DSR starts up the touch panel [logical] processing
> static void
> lcd_panel_dsr(cyg_vector_t vector, cyg_ucount32 count, cyg_addrword_t data)
> {
> 
>     cyg_drv_interrupt_unmask(CYGNUM_HAL_INTERRUPT_EINT2);
> //    cyg_semaphore_post(&lcd_panel_sem);
> }


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Gary Thomas                  |
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