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Programmable Interrupt Controller Registers
12-22
élanSC520 Microcontroller Register Set Manual
Register Description
These registers map each of the interrupt sources (except for ECC and PCI Host Bridge interrupts, see page 12-19
and page 12-17, respectively) to their desired interrupt channel or NMI.
Bit Definitions
Programming Notes
This register should be programmed only when the corresponding interrupt channel mask bits are set in the PIC.
For NMIs, this register should be programmed only when bit NMI_ENB is cleared in the PICICR register (see page 12-4).
NMI_ENB can be set immediately after programming this mapping register to allow NMIs to be passed to the CPU.
Bit
Name
Function
7
–
5
Reserved
Reserved
This bit field should be written to 0 for normal system operation.
4
–
0
INT_MAP
[4–0]
Interrupt Mapping
The value in this 5-bit field maps the interrupt source for the register to one of the following
interrupt priority channels on the microcontroller or as an NMI.
00000 = Disables the interrupt source as an input
00001 = Priority P1 (Master PIC IR0) (Highest priority)
00010 = Priority P2 (Master PIC IR1)
00011 = Priority P3 (Slave 1 PIC IR0/Master PIC IR2)
00100 = Priority P4 (Slave 1 PIC IR1)
00101 = Priority P5 (Slave 1 PIC IR2)
00110 = Priority P6 (Slave 1 PIC IR3)
00111 = Priority P7 (Slave 1 PIC IR4)
01000 = Priority P8 (Slave 1 PIC IR5)
01001 = Priority P9 (Slave 1 PIC IR6)
01010 = Priority P10 (Slave 1 PIC IR7)
01011 = Priority P11 (Master PIC IR3)
01100 = Priority P12 (Master PIC IR4)
01101 = Priority P13 (Slave 2 PIC IR0/Master PIC IR5)
01110 = Priority P14 (Slave 2 PIC IR1)
01111 = Priority P15 (Slave 2 PIC IR2)
10000 = Priority P16 (Slave 2 PIC IR3)
10001 = Priority P17 (Slave 2 PIC IR4)
10010 = Priority P18 (Slave 2 PIC IR5)
10011 = Priority P19 (Slave 2 PIC IR6)
10100 = Priority P20 (Slave 2 PIC IR7)
10101 = Priority P21 (Master PIC IR6)
10110 = Priority P22 (Master PIC IR7) (Lowest priority)
10111 – 11110 = Disables the interrupt source as an input
11111 = NMI source
For example, if INT_MAP = 01101b, the interrupt request is mapped to interrupt priority P13 in
the microcontroller. If INT_MAP = 00000b or any binary value from 10111–11110b, the
interrupt request is disabled from reaching the microcontroller’s PIC. If this field is set to
11111b, then the interrupt is routed to generate an NMI.
If bit S2 in the MPICICW3 register is cleared (see page 12-34), the Slave 1 PIC is bypassed,
so programming the INT_MAP bit field to a value in the range 00100–01010b does not pass
the interrupt request to the CPU. However, if this bit field is programmed to 00011b with the
S2 bit cleared, the interrupt request is routed to the Master PIC IR2 input.
If bit S5 in the MPICICW3 register is cleared (see page 12-33), the Slave 2 PIC is bypassed,
so programming the INT_MAP bit field to a value in the range 01110–10100b does not pass
the interrupt request to the CPU. However, if this field is programmed to 01101b with the S5
bit cleared, the interrupt request is routed to Master PIC IR5 input.