Interrupt Controller (INTC)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
Freescale Semiconductor
9-15
Preliminary
9.4
Functional Description
The functional description involves the areas of interrupt request sources, priority management, and
handshaking with the processor.
9.4.1
Interrupt Request Sources
The INTC has two types of interrupt requests, peripheral and software settable. These interrupt requests
can assert on any clock cycle.
NOTE
The INTC has no spurious vector support. Therefore, if an asserted
peripheral or software settable interrupt request whose PRI
n
value in
INTC_PSR0_3–INTC_PSR292_293 is higher than the PRI value in
INTC_CPR_PRC0 or INTC_CPR_PRC1 negates before the interrupt
request to the processor for that peripheral or software settable interrupt
request is acknowledged, the interrupt request to the processor can assert or
remain asserted for that peripheral or software settable interrupt request. In
this case, the interrupt vector will correspond to that peripheral or software
settable interrupt request. Also, the PRI value in either the
INTC_CPR_PRC0 or INTC_CPR_PRC1 will be updated with the
corresponding PRI
n
value in INTC_PSR
n
_
n
. Furthermore, clearing the
peripheral interrupt request’s enable bit in the peripheral or, alternatively,
setting its mask bit has the same consequences as clearing its flag bit.
Setting its enable bit or clearing its mask bit while its flag bit is asserted has
the same effect on the INTC as an interrupt event setting the flag bit.
9.4.1.1
Peripheral Interrupt Requests
An interrupt event in a peripheral’s hardware sets a flag bit that resides in the peripheral. The interrupt
request from the peripheral is driven by that flag bit.
The time from when the peripheral starts to drive its peripheral interrupt request to the INTC to the time
that the INTC starts to drive the interrupt request to the processor is three clocks.
Interrupt requests from devices external to the MPC5510 are classified as peripheral interrupt requests in
this reference manual. External interrupts are handled by the SIU (see
Section 6.4.3, “External Interrupt
9.4.1.2
Software Settable Interrupt Requests
An interrupt request is triggered by software by writing a 1 to a SETn bit in
INTC_SSCIR0_3–INTC_SSCIR4_7. This write sets the corresponding flag bit, CLRn, resulting in the
interrupt request. The interrupt request is cleared by writing a 1 to the CLRn bit.
The time from the write to the SETn bit to the time that the INTC starts to drive the interrupt request to the
processor is four clocks.