Register Descriptions

10.3.5Interrupt Acknowledge Level and Priority Register (IACKLPRn)

Each time an IACK is performed, the interrupt controller responds with the vector number of the highest priority source within the level being acknowledged. In addition to providing the vector number directly for the byte-sized IACK read, this 8-bit register is also loaded with information about the interrupt level and priority being acknowledged. This register provides the association between the acknowledged “physical” interrupt request number and the programmed interrupt level/priority. The contents of this read-only register are described in Figure 10-8and Table 10-11.

Field

Reset

R/W

Address

7

6

4

3

0

 

LEVEL

 

PRI

 

 

 

 

 

0000_0000

R

IPSBAR + 0xC19, 0xD19

 

 

Figure 10-8. IACK Level and Priority Register (IACKLPRn)

 

 

 

 

Table 10-11. IACKLPRn Field Descriptions

 

 

 

 

 

Bits

Name

 

 

Description

 

 

 

 

7

 

Reserved

 

 

 

 

6–4

LEVEL

 

Interrupt level. Represents the interrupt level currently being acknowledged.

 

 

 

 

3–0

PRI

 

Interrupt Priority. Represents the priority within the interrupt level of the interrupt currently being

 

 

 

acknowledged.

 

 

 

0

Priority 0

 

 

 

1

Priority 1

 

 

 

2

Priority 2

 

 

 

3

Priority 3

 

 

 

4

Priority 4

 

 

 

5

Priority 5

 

 

 

6

Priority 6

 

 

 

7

Priority 7

 

 

 

8

Mid-Point Priority associated with the fixed level interrupts only

 

 

 

 

 

10.3.6 Interrupt Control Register (ICRnx, (x = 1, 2,..., 63))

Each ICRnx specifies the interrupt level (1-7) and the priority within the level (0-7). All ICRnx registers can be read, but only ICRn8 to ICRn63 can be written. It is software’s responsibility to program the ICRnx registers with unique and non-overlapping level and priority definitions. Failure to program the ICRnx registers in this manner can result in undefined behavior. If a specific interrupt request is completely unused, the ICRnx value can remain in its reset (and disabled) state.

MOTOROLA

Chapter 10. Interrupt Controller Modules

10-11

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Image 239
Motorola MCF5281 Interrupt Acknowledge Level and Priority Register IACKLPRn, Interrupt Control Register ICRnx, x = 1, 2