ST72361J4-AUTO View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ST72361J4-AUTO

8-bit MCU for automotive with Flash or ROM, 10-bit ADC, 5 timers, SPI, LINSCI™

STMicroelectronics 

ST72361xx-Auto

Table 12. Interrupt software priority levels

Interrupt software priority

Level

Level 0 (main)

Level 1

Level 2

Level 3 (= interrupt disable)

Low

High

I1

1

0

1

Interrupts

I0

0

1

0

1

Figure 17. Interrupt processing flowchart

RESET

RESTORE PC, X, A, CC

FROM STACK

PENDING

Y

INTERRUPT

N

TLI

Y

Interrupt has the same or a

lower software priority

than current one

N

I1:0

FETCH NEXT

INSTRUCTION

THE INTERRUPT

STAYS PENDING

Y

“IRET”

N

EXECUTE

INSTRUCTION

STACK PC, X, A, CC

LOAD I1:0 FROM INTERRUPT SW REG.

LOAD PC FROM INTERRUPT VECTOR

Servicing pending interrupts

As several interrupts can be pending at the same time, the interrupt to be taken into account

is determined by the following two-step process:

● the highest software priority interrupt is serviced,

● if several interrupts have the same software priority then the interrupt with the highest

hardware priority is serviced first.

Figure 18 describes this decision process.

Figure 18. Priority decision process

PENDING

INTERRUPTS

Same

SOFTWARE

PRIORITY

Different

HIGHEST HARDWARE

PRIORITY SERVICED

HIGHEST SOFTWARE

PRIORITY SERVICED

Doc ID 12468 Rev 3

49/279

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