MC56F8347 Freescale Semiconductor, Inc, MC56F8347 Datasheet - Page 75

• Manufacturer Part Number: MC56F8347
• Description: 56f8300 16-bit Digital Signal Controllers
• Manufacturer: Freescale Semiconductor, Inc

5.3.3
Fast interrupts are described in the DSP56800E Reference Manual. The interrupt controller recognizes
fast interrupts before the core does.
A fast interrupt is defined (to the ITCN) by:
When an interrupt occurs, its vector number is compared with the FIM0 and FIM1 register values. If a
match occurs, and it is a level 2 interrupt, the ITCN handles it as a fast interrupt. The ITCN takes the vector
address from the appropriate FIVALn and FIVAHn registers, instead of generating an address that is an
offset from the VBA.
The core then fetches the instruction from the indicated vector adddress and if it is not a JSR, the core starts
its fast interrupt handling.
Freescale Semiconductor
Preliminary
1. Setting the priority of the interrupt as level 2, with the appropriate field in the IPR registers
2. Setting the FIMn register to the appropriate vector number
3. Setting the FIVALn and FIVAHn registers with the address of the code for the fast interrupt
Fast Interrupt Handling
1. See IPIC field definition in
IPIC_LEVEL[1:0]
00
01
01
11
Table 5-2. Interrupt Priority Encoding
1
No Interrupt or SWILP
Priority 0
Priority 1
Priorities 2 or 3
56F8347 Technical Data, Rev.11
Current Interrupt Priority
Part 5.6.30.2
Level
Priorities 0, 1, 2, 3
Priorities 1, 2, 3
Priorities 2, 3
Priority 3
Exception Priority
Required Nested
Functional Description
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