Motorola ColdFire MCF5281 - Manual (Page 193)

Interrupt Controller Modules
Freescale Semiconductor 10-3
The level and priority is fully programmable for all sources except interrupt sources 1–7. Interrupt source
1–7 (from the Edgeport module) are fixed at the corresponding level’s midpoint priority. Thus, a maximum
of 8 fully-programmable interrupt sources are mapped into a single interrupt level. The “fixed” interrupt
source is hardwired to the given level, and represents the mid-point of the priority within the level. For the
fully-programmable interrupt sources, the 3-bit level and the 3-bit priority within the level are defined in
the 8-bit interrupt control register (ICRnx).
The operation of the interrupt controller can be broadly partitioned into three activities:
• Recognition
• Prioritization
• Vector Determination during IACK
10.1.1.1 Interrupt Recognition
The interrupt controller continuously examines the request sources and the interrupt mask register to
determine if there are active requests. This is the recognition phase.
6
7–4 #8–63
— (Mid-point) #6 (IRQ6)
3–0 #8–63
5
7–4 #8–63
— (Mid-point) #5 (IRQ5)
3–0 #8–63
4
7–4 #8–63
— (Mid-point) #4 (IRQ4)
3–0 #8–63
3
7–4 #8–63
— (Mid-point) #3 (IRQ3)
3–0 #8–63
2
7–4 #8–63
— (Mid-point) #2 (IRQ2)
3–0 #8–63
1
7–4 #8–63
— (Mid-point) #1 (IRQ1)
3–0 #8–63
Table 10-1. Interrupt Priority Scheme (continued)
Interrupt
Level
ICR[IL]
Priority
ICR[IP]
Supported Interrupt
Sources
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3