+++ /dev/null
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-><HEAD
-><TITLE
->Interrupt Handling</TITLE
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-><A
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->Prev</A
-></TD
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->Chapter 9. HAL Interfaces</TD
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-><HR
-ALIGN="LEFT"
-WIDTH="100%"></DIV
-><DIV
-CLASS="SECTION"
-><H1
-CLASS="SECTION"
-><A
-NAME="HAL-INTERRUPT-HANDLING">Interrupt Handling</H1
-><P
->These interfaces contain definitions related to interrupt
-handling. They include definitions of exception and interrupt numbers,
-interrupt enabling and masking, and realtime clock operations.</P
-><P
->These definitions are normally found in
-<TT
-CLASS="FILENAME"
->cyg/hal/hal_intr.h</TT
->. This file is supplied by the
-architecture HAL. Any variant or platform specific definitions will
-be found in <TT
-CLASS="FILENAME"
->cyg/hal/var_intr.h</TT
->,
-<TT
-CLASS="FILENAME"
->cyg/hal/plf_intr.h</TT
-> or
-<TT
-CLASS="FILENAME"
->cyg/hal/hal_platform_ints.h</TT
-> in the variant or platform
-HAL, depending on the exact target. These files are include
-automatically by this header, so need not be included explicitly.</P
-><DIV
-CLASS="SECTION"
-><H2
-CLASS="SECTION"
-><A
-NAME="AEN7921">Vector numbers</H2
-><TABLE
-BORDER="5"
-BGCOLOR="#E0E0F0"
-WIDTH="70%"
-><TR
-><TD
-><PRE
-CLASS="PROGRAMLISTING"
->CYGNUM_HAL_VECTOR_XXXX
-CYGNUM_HAL_VSR_MIN
-CYGNUM_HAL_VSR_MAX
-CYGNUM_HAL_VSR_COUNT
-
-CYGNUM_HAL_INTERRUPT_XXXX
-CYGNUM_HAL_ISR_MIN
-CYGNUM_HAL_ISR_MAX
-CYGNUM_HAL_ISR_COUNT
-
-CYGNUM_HAL_EXCEPTION_XXXX
-CYGNUM_HAL_EXCEPTION_MIN
-CYGNUM_HAL_EXCEPTION_MAX
-CYGNUM_HAL_EXCEPTION_COUNT</PRE
-></TD
-></TR
-></TABLE
-><P
->All possible VSR, interrupt and exception vectors are specified here,
-together with maximum and minimum values for range checking. While the
-VSR and exception numbers will be defined in this file, the interrupt
-numbers will normally be defined in the variant or platform HAL file
-that is included by this header. </P
-><P
->There are two ranges of numbers, those for the vector service
-routines and those for the interrupt service routines. The relationship
-between these two ranges is undefined, and no equivalence should
-be assumed if vectors from the two ranges coincide.</P
-><P
->The VSR vectors correspond to the set of exception vectors that can be
-delivered by the CPU architecture, many of these will be internal
-exception traps. The ISR vectors correspond to the set of external
-interrupts that can be delivered and are usually determined by extra
-decoding of the interrupt controller by the interrupt VSR.</P
-><P
->Where a CPU supports synchronous exceptions, the range of such
-exceptions allowed are defined by <TT
-CLASS="LITERAL"
->CYGNUM_HAL_EXCEPTION_MIN</TT
-> and
-<TT
-CLASS="LITERAL"
->CYGNUM_HAL_EXCEPTION_MAX</TT
->. The
-<TT
-CLASS="LITERAL"
->CYGNUM_HAL_EXCEPTION_XXXX</TT
-> definitions are
-standard names used by target independent code to test for the
-presence of particular exceptions in the architecture. The actual
-exception numbers will normally correspond to the VSR exception
-range. In future other exceptions generated by the system software
-(such as stack overflow) may be added.</P
-><P
-><TT
-CLASS="LITERAL"
->CYGNUM_HAL_ISR_COUNT</TT
->, <TT
-CLASS="LITERAL"
->CYGNUM_HAL_VSR_COUNT</TT
-> and
-<TT
-CLASS="LITERAL"
->CYGNUM_HAL_EXCEPTION_COUNT</TT
-> define the number of
-ISRs, VSRs and EXCEPTIONs respectively for the purposes of defining
-arrays etc. There might be a translation from the supplied vector
-numbers into array offsets. Hence
-<TT
-CLASS="LITERAL"
->CYGNUM_HAL_XXX_COUNT</TT
-> may not simply be
-<TT
-CLASS="LITERAL"
->CYGNUM_HAL_XXX_MAX</TT
-> - <TT
-CLASS="LITERAL"
->CYGNUM_HAL_XXX_MIN</TT
-> or <TT
-CLASS="LITERAL"
->CYGNUM_HAL_XXX_MAX</TT
->+1.</P
-></DIV
-><DIV
-CLASS="SECTION"
-><H2
-CLASS="SECTION"
-><A
-NAME="AEN7939">Interrupt state control</H2
-><TABLE
-BORDER="5"
-BGCOLOR="#E0E0F0"
-WIDTH="70%"
-><TR
-><TD
-><PRE
-CLASS="PROGRAMLISTING"
->CYG_INTERRUPT_STATE
-HAL_DISABLE_INTERRUPTS( old )
-HAL_RESTORE_INTERRUPTS( old )
-HAL_ENABLE_INTERRUPTS()
-HAL_QUERY_INTERRUPTS( state )</PRE
-></TD
-></TR
-></TABLE
-><P
->These macros provide control over the state of the CPUs interrupt mask
-mechanism. They should normally manipulate a CPU status register to
-enable and disable interrupt delivery. They should not access an
-interrupt controller.</P
-><P
-><TT
-CLASS="LITERAL"
->CYG_INTERRUPT_STATE</TT
-> is a data type that should be
-used to store the interrupt state returned by
-<TT
-CLASS="FUNCTION"
->HAL_DISABLE_INTERRUPTS()</TT
-> and
-<TT
-CLASS="FUNCTION"
->HAL_QUERY_INTERRUPTS()</TT
-> and passed to
-<TT
-CLASS="FUNCTION"
->HAL_RESTORE_INTERRUPTS()</TT
->.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_DISABLE_INTERRUPTS()</TT
-> disables the delivery of
-interrupts and stores the original state of the interrupt mask in the
-variable passed in the <TT
-CLASS="PARAMETER"
-><I
->old</I
-></TT
-> argument.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_RESTORE_INTERRUPTS()</TT
-> restores the state of
-the interrupt mask to that recorded in <TT
-CLASS="PARAMETER"
-><I
->old</I
-></TT
->.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_ENABLE_INTERRUPTS()</TT
-> simply enables interrupts
-regardless of the current state of the mask.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_QUERY_INTERRUPTS()</TT
-> stores the state of the
-interrupt mask in the variable passed in the <TT
-CLASS="PARAMETER"
-><I
->state</I
-></TT
-> argument. The state stored here should also be
-capable of being passed to
-<TT
-CLASS="FUNCTION"
->HAL_RESTORE_INTERRUPTS()</TT
-> at a later point.</P
-><P
->It is at the HAL implementer’s discretion exactly
-which interrupts are masked by this mechanism. Where a CPU has more
-than one interrupt type that may be masked separately (e.g. the
-ARM's IRQ and FIQ) only those that can raise DSRs need
-to be masked here. A separate architecture specific mechanism may
-then be used to control the other interrupt types.</P
-></DIV
-><DIV
-CLASS="SECTION"
-><H2
-CLASS="SECTION"
-><A
-NAME="AEN7961">ISR and VSR management</H2
-><TABLE
-BORDER="5"
-BGCOLOR="#E0E0F0"
-WIDTH="70%"
-><TR
-><TD
-><PRE
-CLASS="PROGRAMLISTING"
->HAL_INTERRUPT_IN_USE( vector, state )
-HAL_INTERRUPT_ATTACH( vector, isr, data, object )
-HAL_INTERRUPT_DETACH( vector, isr )
-HAL_VSR_SET( vector, vsr, poldvsr )
-HAL_VSR_GET( vector, pvsr )
-HAL_VSR_SET_TO_ECOS_HANDLER( vector, poldvsr )</PRE
-></TD
-></TR
-></TABLE
-><P
->These macros manage the attachment of interrupt and vector service
-routines to interrupt and exception vectors respectively.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_INTERRUPT_IN_USE()</TT
-> tests the state of the
-supplied interrupt vector and sets the value of the state parameter to
-either 1 or 0 depending on whether there is already an ISR attached to
-the vector. The HAL will only allow one ISR to be attached to each
-vector, so it is a good idea to use this function before using
-<TT
-CLASS="FUNCTION"
->HAL_INTERRUPT_ATTACH()</TT
->.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_INTERRUPT_ATTACH()</TT
-> attaches
-the ISR, data pointer and object pointer to the given
-<TT
-CLASS="PARAMETER"
-><I
->vector</I
-></TT
->. When an interrupt occurs on this
-vector the ISR is called using the C calling convention and the vector
-number and data pointer are passed to it as the first and second
-arguments respectively.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_INTERRUPT_DETACH()</TT
-> detaches the ISR from the
-vector.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_VSR_SET()</TT
-> replaces the VSR attached to the
-<TT
-CLASS="PARAMETER"
-><I
->vector</I
-></TT
-> with the replacement supplied in
-<TT
-CLASS="PARAMETER"
-><I
->vsr</I
-></TT
->. The old VSR is returned in the location
-pointed to by <TT
-CLASS="PARAMETER"
-><I
->pvsr</I
-></TT
->.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_VSR_GET()</TT
-> assigns
-a copy of the VSR to the location pointed to by <TT
-CLASS="PARAMETER"
-><I
->pvsr</I
-></TT
->.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_VSR_SET_TO_ECOS_HANDLER()</TT
-> ensures that the
-VSR for a specific exception is pointing at the eCos exception VSR and
-not one for RedBoot or some other ROM monitor. The default when
-running under RedBoot is for exceptions to be handled by RedBoot and
-passed to GDB. This macro diverts the exception to eCos so that it may
-be handled by application code. The arguments are the VSR vector to be
-replaces, and a location in which to store the old VSR pointer, so
-that it may be replaced at a later point.</P
-></DIV
-><DIV
-CLASS="SECTION"
-><H2
-CLASS="SECTION"
-><A
-NAME="AEN7983">Interrupt controller management</H2
-><TABLE
-BORDER="5"
-BGCOLOR="#E0E0F0"
-WIDTH="70%"
-><TR
-><TD
-><PRE
-CLASS="PROGRAMLISTING"
->HAL_INTERRUPT_MASK( vector )
-HAL_INTERRUPT_UNMASK( vector )
-HAL_INTERRUPT_ACKNOWLEDGE( vector )
-HAL_INTERRUPT_CONFIGURE( vector, level, up )
-HAL_INTERRUPT_SET_LEVEL( vector, level )</PRE
-></TD
-></TR
-></TABLE
-><P
->These macros exert control over any prioritized interrupt
-controller that is present. If no priority controller exists, then
-these macros should be empty.</P
-><DIV
-CLASS="NOTE"
-><BLOCKQUOTE
-CLASS="NOTE"
-><P
-><B
->Note: </B
-> These macros may not be reentrant, so care should be taken to
- prevent them being called while interrupts are enabled. This means
- that they can be safely used in initialization code before
- interrupts are enabled, and in ISRs. In DSRs, ASRs and thread code,
- however, interrupts must be disabled before these macros are
- called. Here is an example for use in a DSR where the interrupt
- source is unmasked after data processing:
- </P
-><TABLE
-BORDER="5"
-BGCOLOR="#E0E0F0"
-WIDTH="70%"
-><TR
-><TD
-><PRE
-CLASS="PROGRAMLISTING"
-> ...
- HAL_DISABLE_INTERRUPTS(old);
- HAL_INTERRUPT_UNMASK(CYGNUM_HAL_INTERRUPT_ETH);
- HAL_RESTORE_INTERRUPTS(old);
- ...</PRE
-></TD
-></TR
-></TABLE
-></BLOCKQUOTE
-></DIV
-><P
-><TT
-CLASS="FUNCTION"
->HAL_INTERRUPT_MASK()</TT
-> causes the interrupt
-associated with the given vector to be blocked.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_INTERRUPT_UNMASK()</TT
-> causes the interrupt
-associated with the given vector to be unblocked.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_INTERRUPT_ACKNOWLEDGE()</TT
-> acknowledges the
-current interrupt from the given vector. This is usually executed from
-the ISR for this vector when it is prepared to allow further
-interrupts. Most interrupt controllers need some form of acknowledge
-action before the next interrupt is allowed through. Executing this
-macro may cause another interrupt to be delivered. Whether this
-interrupts the current code depends on the state of the CPU interrupt
-mask.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_INTERRUPT_CONFIGURE()</TT
-> provides
-control over how an interrupt signal is detected. The arguments
-are:</P
-><P
-></P
-><DIV
-CLASS="VARIABLELIST"
-><DL
-><DT
->vector</DT
-><DD
-><P
->The interrupt vector to be configured.</P
-></DD
-><DT
->level</DT
-><DD
-><P
-> Set to <TT
-CLASS="VARNAME"
->true</TT
-> if the interrupt is detected by
- level, and <TT
-CLASS="VARNAME"
->false</TT
-> if it is edge triggered.
- </P
-></DD
-><DT
->up</DT
-><DD
-><P
-> If the interrupt is set to level detect, then if this is
- <TT
-CLASS="VARNAME"
->true</TT
-> it is detected by a high signal level,
- and if <TT
-CLASS="VARNAME"
->false</TT
-> by a low signal level. If the
- interrupt is set to edge triggered, then if this is
- <TT
-CLASS="VARNAME"
->true</TT
-> it is triggered by a rising edge and if
- <TT
-CLASS="VARNAME"
->false</TT
-> by a falling edge.
- </P
-></DD
-></DL
-></DIV
-><P
-><TT
-CLASS="FUNCTION"
->HAL_INTERRUPT_SET_LEVEL()</TT
-> provides control over
-the hardware priority of the interrupt. The arguments are:</P
-><P
-></P
-><DIV
-CLASS="VARIABLELIST"
-><DL
-><DT
->vector</DT
-><DD
-><P
->The interrupt whose level is to be set.</P
-></DD
-><DT
->level</DT
-><DD
-><P
-> The priority level to which the interrupt is to set. In some
- architectures the masking of an interrupt is achieved by
- changing its priority level. Hence this function,
- <TT
-CLASS="FUNCTION"
->HAL_INTERRUPT_MASK()</TT
-> and
- <TT
-CLASS="FUNCTION"
->HAL_INTERRUPT_UNMASK()</TT
-> may interfere with
- each other.
- </P
-></DD
-></DL
-></DIV
-></DIV
-><DIV
-CLASS="SECTION"
-><H2
-CLASS="SECTION"
-><A
-NAME="AEN8030">Clock control</H2
-><TABLE
-BORDER="5"
-BGCOLOR="#E0E0F0"
-WIDTH="70%"
-><TR
-><TD
-><PRE
-CLASS="PROGRAMLISTING"
->HAL_CLOCK_INITIALIZE( period )
-HAL_CLOCK_RESET( vector, period )
-HAL_CLOCK_READ( pvalue )</PRE
-></TD
-></TR
-></TABLE
-><P
->These macros provide control over a clock or timer device that may be
-used by the kernel to provide time-out, delay and scheduling
-services. The clock is assumed to be implemented by some form of
-counter that is incremented or decremented by some external source and
-which raises an interrupt when it reaches a predetermined value.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_CLOCK_INITIALIZE()</TT
-> initializes the timer
-device to interrupt at the given period. The period is essentially the
-value used to initialize the timer counter and must be calculated from
-the timer frequency and the desired interrupt rate. The timer device
-should generate an interrupt every <TT
-CLASS="VARNAME"
->period</TT
-> cycles.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_CLOCK_RESET()</TT
-> re-initializes the timer to
-provoke the next interrupt. This macro is only really necessary when
-the timer device needs to be reset in some way after each interrupt.</P
-><P
-><TT
-CLASS="FUNCTION"
->HAL_CLOCK_READ()</TT
-> reads the current value of the
-timer counter and puts the value in the location pointed to by
-<TT
-CLASS="PARAMETER"
-><I
->pvalue</I
-></TT
->. The value stored will always be the
-number of timer cycles since the last interrupt, and hence ranges
-between zero and the initial period value. If this is a count-down
-cyclic timer, some arithmetic may be necessary to generate this value.</P
-></DIV
-><DIV
-CLASS="SECTION"
-><H2
-CLASS="SECTION"
-><A
-NAME="AEN8042">Microsecond Delay</H2
-><TABLE
-BORDER="5"
-BGCOLOR="#E0E0F0"
-WIDTH="70%"
-><TR
-><TD
-><PRE
-CLASS="PROGRAMLISTING"
->HAL_DELAY_US(us)</PRE
-></TD
-></TR
-></TABLE
-><P
->This is an optional definition. If defined the macro implements a busy
-loop delay for the given number of microseconds. This is usually
-implemented by waiting for the required number of hardware timer ticks
-to pass. </P
-><P
->This operation should normally be used when a very short delay is
-needed when controlling hardware, programming FLASH devices and similar
-situations where a wait/timeout loop would otherwise be used. Since it
-may disable interrupts, and is implemented by busy waiting, it should
-not be used in code that is sensitive to interrupt or context switch
-latencies.</P
-></DIV
-></DIV
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-WIDTH="100%"><TABLE
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