PQFP100 datasheet(96/429 Pages) STMICROELECTRONICS

Part #	PQFP100

Description	8/16-BIT SINGLE VOLTAGE FLASH MCU FAMILY WITH RAM, E3 TM(EMULATED EEPROM), CAN 2.0B AND J1850 BLPD

PDF	429 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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ST92F124/F150/F250 - INTERRUPTS

ARBITRATION MODES (Cont’d)

Examples

In the following two examples, three interrupt re-

quests with different priority levels (2, 3 & 4) occur

simultaneously during the interrupt 5 service rou-

tine.

Example 1

In the first example, (simplest case, Figure 46) the

instruction is not used within the interrupt serv-

ice routines. This means that no new interrupt can

be serviced in the middle of the current one. The

interrupt routines will thus be serviced one after

another, in the order of their priority, until the main

program eventually resumes.

Figure 46. Simple Example of a Sequence of Interrupt Requests with:

- Concurrent mode selected and

- IEN unchanged by the interrupt routines

Priority Level of

MAIN

INT 5

INT 2

INT 3

INT 4

MAIN

INT 5

INT 4

INT 3

INT 2

CPL is set to 7

CPL = 7

INTERRUPT 2 HAS PRIORITY LEVEL 2

INTERRUPT 3 HAS PRIORITY LEVEL 3

INTERRUPT 4 HAS PRIORITY LEVEL 4

INTERRUPT 5 HAS PRIORITY LEVEL 5

Interrupt Request

PQFP100 Datasheet(PDF) 96 Page - STMicroelectronics