PROGRAMMER'S MODEL
SC32442B RISC MICROPROCESSOR
2-14
Exception Priorities
When multiple exceptions arise at the same time, a fixed priority system determines the order in which they are
handled:
Highest priority:
1. Reset
2. Data abort
3. FIQ
4. IRQ
5. Prefetch abort
Lowest priority:
6. Undefined Instruction, Software interrupt.
Not All Exceptions Can Occur at Once:
Undefined Instruction and Software Interrupt are mutually exclusive, since they each correspond to particular
(non-overlapping) decodings of the current instruction.
If a data abort occurs at the same time as a FIQ, and FIQs are enabled (ie the CPSR's F flag is clear), ARM920T
enters the data abort handler and then immediately proceeds to the FIQ vector. A normal return from FIQ will
cause the data abort handler to resume execution. Placing data abort at a higher priority than FIQ is necessary to
ensure that the transfer error does not escape detection. The time for this exception entry should be added to
worst-case FIQ latency calculations.
Содержание SC32442B54
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Страница 59: ...PROGRAMMER S MODEL SC32442B RISC MICROPROCESSOR 2 16 NOTES ...
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Страница 167: ...THUMB INSTRUCTION SET SC32442B RISC MICROPROCESSOR 4 44 NOTES ...
Страница 187: ...MEMORY CONTROLLER SC32442B RISC MICROPROCESSOR 5 20 NOTES ...
Страница 250: ...DMA SC32442B RISC MICROPROCESSOR 8 14 NOTES ...
Страница 308: ...PWM TIMER SC32442B RISC MICROPROCESSOR 10 20 NOTES ...
Страница 330: ...UART SC32442B RISC MICROPROCESSOR 11 22 NOTES ...
Страница 417: ...SC32442B RISC MICROPROCESSOR LCD CONTROLLER 15 45 NOTES ...
Страница 427: ...ADC AND TOUCH SCREEN INTERFACE SC32442B RISC MICROPROCESSOR 16 10 NOTES ...
Страница 511: ...BUS PRIORITIES SC32442B RISC MICROPROCESSOR 24 2 NOTES ...
Страница 562: ...K5D2G13ACM D075 Revision 1 0 December 2006 7 MCP MEMORY 2Gb 256Mb x8 NAND Flash Memory A Die ...
Страница 599: ...K5D2G13ACM D075 Revision 1 0 December 2006 44 MCP MEMORY 512Mb 16Mb x32 Mobile SDRAM C Die ...