System Configuration and Protection
MPC561/MPC563 Reference Manual, Rev. 1.2
6-10
Freescale Semiconductor
The decrementer interrupt request is not a part of the interrupt controller. Each one of the external pins
IRQ[1:7] has its own dedicated assigned priority level. IRQ0 is also mapped, but it should be used only as
a status bit indicating that IRQ0 was asserted and generated NMI interrupt. There are eight additional
interrupt priority levels. Each one of the SIU internal interrupt sources, or any of the peripheral module
interrupt sources can be assigned by software to any one of the eight interrupt priority levels. Thus, a very
flexible interrupt scheme is implemented. The interrupt request signal generated by the interrupt controller
is driven to the RPCU core and to the IRQOUT pin (optionally). This pin may be used in peripheral mode,
when the RCPU is disabled, and the internal modules are accessed externally. The IMB interrupts are
controlled by the UIMB. The IMB provides 32 interrupt levels, and any interrupt source could be
configured to any IMB interrupt level. The UIMB contains a 32-bit register that holds the IMB interrupt
requests, and maps them to the USIU eight interrupt levels.
NOTE
If one interrupt level was configured to more than one interrupt source, the
software should read the UIPEND register in the UIMB module, and the
particular status bits in order to identify which interrupt was asserted.
The interrupt controller may be programmed to operate in two modes—a regular mode or an enhanced
mode.
6.1.4.3
Regular Interrupt Controller Operation (MPC555/MPC556-Compatible
Mode)
In regular operation mode (default setting) the interrupt controller receives interrupt requests from internal
sources, such as timers, PLL lock detector, IMB modules and from external pins IRQ[0:7]. All the internal
interrupt sources may be programmed to drive one or more of eight U-bus interrupt level lines while the
RCPU, upon receiving an interrupt request, has to read the USIU and UIMB status register in order to
determine the interrupt source.
The SIVEC register contains an 8-bit code representing the unmasked interrupt request which has the
highest priority level. The priority between all interrupt sources for the regular interrupt controller
operation is shown in
.
Table 6-3. Priority of Interrupt Sources—Regular Operation
Number
Priority
Level
Interrupt Source
Description
Offset in Branch
Table (Hex)
SIVEC Interrupt Code
1
0
Highest
EXT_IRQ0
0x0000 00000000
1 —
Level
0
0x0008
00000100
2
—
EXT_IRQ1
0x0010 00001000
3
—
Level 1
0x0018
00001100
4
—
EXT_IRQ2
0x0020 00010000
5
—
Level 2
0x0028
00010100
6
—
EXT_IRQ3
0x0030 00011000
7
—
Level 3
0x0038
00011100
Summary of Contents for MPC561
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Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
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Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...