Motorola DSP56301 - Manual (Page 93)

Configuring Interrupts
Core Configuration 4 -19
4.4.3 Processing Interrupt Source Priorities Within an IPL
If more than one interrupt request is pending when an instruction executes, the interrupt
source with the highest IPL is serviced first. When several interrupt requests with the same
IPL are pending, another fixed-priority structure within that IPL determines which interrupt
source is serviced first. Table 4-7 shows this fixed-priority list of interrupt sources within an
IPL, from highest to lowest at each level
The interrupt mask bits in the Status Register
(I[1–0]) can be programmed to ignore low priority-level interrupt requests.
VBA:$52 0–2 SCI receive data with exception status
VBA:$54 0–2 SCI transmit data
VBA:$56 0–2 SCI idle line
VBA:$58 0–2 SCI timer
VBA:$5A 0–2 Reserved
VBA:$5C 0–2 Reserved
VBA:$5E 0–2 Reserved
VBA:$60 0–2 Host receive data full
VBA:$62 0–2 Host transmit data empty
VBA:$64 0–2 Host command (default)
VBA:$66 0–2 Reserved
: : :
VBA:$FE 0–2 Reserved
Table 4-7. Interrupt Source Priorities Within an IPL
Priority Interrupt Source
Level 3 (nonmaskable)
Highest Hardware RESET
Stack error
Illegal instruction
Debug request interrupt
Trap
Lowest Nonmaskable interrupt
Levels 0, 1, 2 (maskable)
Highest IRQA (external interrupt)
IRQB (external interrupt)
Table 4-6. Interrupt Sources (Continued)
Interrupt
Starting Address
Interrupt
Priority Level
Range
Interrupt Source