Fujitsu FR family 32-bit microcontroller instruction manue Manual do Utilizador descarregar pdf (Página 75)

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

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

1 2 ... 70 71 72 73 74 75 76 77 78 79 80 ... 313 314

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Fujitsu FR family 32-bit microcontroller instruction manue Manual do Utilizador Página 75