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CHAPTER 4 RESET AND "EIT" PROCESSING
4.6 Priority Levels
When multiple "EIT" requests occur at the same time, priority levels are used to select
one source and execute the corresponding "EIT" sequence. After the "EIT" sequence is
completed, "EIT" request detection is applied again to enable processing of multiple
"EIT" requests.
Acceptance of certain types of "EIT" requests can mask other factors. In such cases the
priority applied by the "EIT" processing handler may not match the priority of the
requests.
■ Priority of Simultaneous Occurrences
The FR family uses a hardware function to determine the priority of acceptance of "EIT" requests.
Table 4.6-1 shows the priority levels of "EIT" requests.
Table 4.6-1 Priority of "EIT" Requests
Priority Source Masking of other sources
1 Reset Other sources discarded
2 Undefined instruction exception Other sources disabled
3
INT instruction I flag = 0
Coprocessor not found trap
Coprocessor error trap
None
4 User interrupt ILM = level of source accepted
5 NMI ILM = 15
6 Step trace trap ILM = 4
7 INTE instruction ILM = 4