System Interface Unit (SIU)
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
4-18 Freescale Semiconductor

The SICR register bits are described in Table 4 -4.

4.3.1.2 SIU Interrupt Priority Register (SIPRR)

The SIU interrupt priority register (SIPRR), shown in Figure4-11, defines the priority between

IRQ1–IRQ5, PIT, PCI, and TMCNT.

The SIPRR register bits are described in Table 4- 5.

Table4-4. SICR Field Descriptions

Bits Name Description
0–1 Reserved, should be cleared.
2–7 HP Highest priority. Specifies the 6-bit interrupt number of the single interrupt controller interrupt source
that is advanced to the highest priority in the table. HP can be modified dynamically. To retain the
original priority, program HP to the interrupt number assigned to XSIU1.
8–13 Reserved, should be cleared.
14 GSIU Group SIU. Selects the relative XSIU priority scheme. It cannot be changed dynamically.
0 Grouped. The XSIUs are grouped by priority at the top of the table.
1 Spread. The XSIUs are spread by priority in the table.
15 SPS Spread priority scheme. Selects the relative YCC priority scheme. It cannot be changed dynamically.
0 Grouped. The YCCs are grouped by priority at the top of the table.
1 Spread. The YCCs are spread by priority in the table.
02356891112 15
Field XS1P XS2P XS3P XS4P
Reset 000 001 010 011 0000
R/W R/W
Addr 0x0x10C10
16 18 19 21 22 24 25 27 28 31
Field XS5P XS6P XS7P XS8P
Reset 100 101 110 111 0000
R/W R/W
Addr 0x10C12

Figure 4-11. SIU Interrupt Priority Register (SIPRR)