PXD20RM Datasheet, PDF (924/1628 Pages) Freescale Semiconductor, Inc – PXD20 Microcontroller

26.3 Block diagram
Figure 26-1 is a block diagram of the INTC.
Software
Set/Clear
Interrupt
Registers
Priority
Select
Registers
Module
Configuration ^Hardware
Register ^{Vector Enable}
1
Peripheral
Interrupt
Requests
Flag Bits
8
n¹
n¹ x
4-bits
Priority
Arbitrator
Highest
Priority
Interrupt
Requests
n¹
Request
Selector
4 Highest Priority
Lowest
Vector
Interrupt
Request
n¹
End of
Interrupt
Register
Vector
Encoder
Vector Table
Entry Size ¹
Interrupt
Vector
9
Processor 0
Interrupt
Acknowledge
Register
Interrupt
Vector
9
Pushed
New
Priority
Priority
4
4
Processor 0
Priority
LIFO
Popped
Priority
4
Processor 0
Current
Priority
Register
Current
Priority
4
Priority
Comparator
Update Interrupt Vector
1
Interrupt
Request to
Processor
1
Interrupt Acknowledge
Push/Update/Acknowledge
Pop
Memory Mapped Registers
Non-Memory Mapped Logic
1 _{The total number of interrupt sources is 187, which includes 8 software sources.}
Figure 26-1. INTC block diagram
1
1 Slave
Interface
1 ^{for Reads}
& Writes
Peripheral
Bus
26.4 Modes of operation
26.4.1 Normal mode
In normal mode, the INTC has two handshaking modes with the processor: software vector mode and
hardware vector mode.
26.4.1.1 Software vector mode
In software vector mode, the interrupt exception handler software must read a register in the INTC to
obtain the vector associated with the interrupt request to the processor. The INTC will use software vector
mode for a given processor when its associated HVEN bit in INTC_MCR is negated. The hardware vector
enable signal to processor 0 or processor 1 is driven as negated when its associated HVEN bit is negated.
The vector is read from INTC_IACKR. Reading the INTC_IACKR negates the interrupt request to the
associated processor. Even if a higher priority interrupt request arrived while waiting for this interrupt
acknowledge, the interrupt request to the processor will negate for at least one clock. The reading also
pushes the PRI value in INTC_CPR onto the associated LIFO and updates PRI in the associated
INTC_CPR with the new priority.
26-2
PXD20 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
Freescale Semiconductor