Interrupt Logic

Figure 2–8 provides an overview of the interrupt control sequence. INT0 is the highest priority interrupt, and INT7 is the lowest priority interrupt.

Figure 2–8. Interrupt Initialization Sequence

INTD

CLEAR

instruction

 

 

 

SET

 

 

 

 

 

 

 

INTE

 

instruction

 

 

 

 

 

Interrupt

Service

Routine

(1 of 8)

INTE

IRET

Global Interrupt Enable

CLEAR

Interrupt-Trigger Event

Internal Timer Underflow

External Input Falling-Edge

External Input Rising-Edge

Software Write Instruction

SET BIT

CLEAR BIT

INT Flag bits (IFR)

 

 

Associated With the Interrupt-Trigger Event

 

 

 

 

Interrupt Flag Register (0x39)

INT7 INT6 INT5 INT4 INT3 INT2 INT1 INT0

INT Mask bits (IMR)

Specific Enable for Interrupt Service

Interrupt / General Control Register (0x38)†

INT7 INT6 INT5 INT4 INT3 INT2 INT1 INT0

Interrupt Service Branch

Highest Priority INT is Selected From

Among Those Flagged and Enabled.

Program Branches to Location

Stored in Interrupt Vector.

Interrupt Vector Storage

0x7FF0 0x7FF2 0x7FF4 0x7FF6 0x7FF1 0x7FF3 0x7FF5 0x7FF7

The port-addressed write instruction (OUT) can be used to SET or CLEAR bits in the IFR and IMR.

MSP50C6xx Architecture

2-25

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Image 49
Texas Instruments MSP50C6xx manual Interrupt Initialization Sequence