Memory Organization: RAM and ROM

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

I/O Map

Width of

Allowable

Control Register Name

Abbreviation

State after

Section for

Address

Location

Access

RESET LOW

Reference

 

 

 

 

 

 

 

 

 

0x39

8 bits

Read & Write

Interrupt flag

IFR

Same state as

2.7

before RESET

 

 

 

 

 

 

 

 

 

 

 

 

 

0x3A

16 bits

Read & Write

TIMER1 period

PRD1

0x0000

 

 

 

 

 

 

 

2.8

0x3B

16 bits

Read & Write

TIMER1 count-down

TIM1

0x0000

 

 

 

 

 

 

 

 

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

 

 

 

 

 

 

 

 

2.6.3Interrupt 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

Event Source

Interrupt Priority

Vector

 

 

 

INT0

0x7FF0

DAC Timer

Highest

INT1

0x7FF1

TIMER1

2nd

INT2

0x7FF2

TIMER2

3rd

INT3

0x7FF3

port D2

4th

INT4

0x7FF4

port D3

5th

INT5

0x7FF5

all port F

6th

INT6

0x7FF6

port D4

7th

INT7

0x7FF7

port D5

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.

2-18

Page 42
Image 42
Texas Instruments MSP50C6xx manual Summary of C614’s Peripheral Communications Ports, Interrupt Vectors