3 interrupt vectors – Texas Instruments MSP50C614 User Manual

Page 48

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Memory Organization: RAM and ROM

2-18

Table 2–2. Summary of C614’s Peripheral Communications Ports (Continued)

I/O Map

Address

Width of

Location

Allowable

Access

Control Register Name

Abbreviation

State after

RESET LOW

Section for

Reference

0x3A

16 bits

read & write

TIMER1 period

PRD1

0x0000

2 8

0x3B

16 bits

read & write

TIMER1 count-down

TIM1

0x0000

2.8

0x3D

16 bits

WRITE only

Clock speed control

ClkSpdCtrl

0x0000

2.9.3

0x3E

16 bits

read & write

TIMER2 period

PRD2

0x0000

2 8

0x3F

16 bits

read & write

TIMER2 count-down

TIM2

0x0000

2.8

2.6.3

Interrupt Vectors

When its event has triggered and its service has been enabled, an interrupt
causes the program counter to branch to a specific location. The destination
location is stored (programmed) in the interrupt vector, which resides in an up-
per address of ROM. The following table lists the ROM address associated
with each interrupt vector:

Interrupt Name

ROM address of

Vector

Event Source

Interrupt Priority

INT0

0x7FF0

DAC Timer

Highest

INT1

0x7FF1

TIMER1

2nd

INT2

0x7FF2

TIMER2

3rd

INT3

0x7FF3

port D

2

4th

INT4

0x7FF4

port D

3

5th

INT5

0x7FF5

all port F

6th

INT6

0x7FF6

port D

4

7th

INT7

0x7FF7

port D

5

Lowest

0x7FFE

storage for ROM Protection Word

RESET

0x7FFF

storage for initialization vector

Note:

ROM Locations that Hold Interrupt Vectors

ROM locations that hold interrupt vectors are reserved specifically for this
purpose. Additional ROM locations 0x7FF8 - 0x7FFD are reserved for future
expansion. Like the interrupt vectors, they should not be used for general
program storage.

The branch to the program location that is specified in the interrupt vector is,
of course, contingent on the occurrence of the trigger event. Refer to Section

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