Analog Devices ADuC812 manual Source Priority Description, Source Vector Address

Models: ADuC812

1 56
Download 56 pages 22.67 Kb
Page 39
Image 39

ADuC812

IE2:

Secondary Interrupt Enable Register

SFR Address

A9H

Power-On Default Value

00H

Bit Addressable

No

EPSMI

ESI

 

 

Table XXV. IE2 SFR Bit Designations

 

 

 

Bit

Name

Description

 

 

 

7

Reserved for Future Use.

6

Reserved for Future Use.

5

Reserved for Future Use.

4

Reserved for Future Use.

3

Reserved for Future Use.

2

Reserved for Future Use.

1

EPSMI

Written by User to Enable “1” or Disable “0” Power Supply Monitor Interrupt.

0

ESI

Written by User to Enable “1” or Disable “0” SPI/I2C Serial Port Interrupt.

Interrupt Priority

The Interrupt Enable registers are written by the user to enable individual interrupt sources, while the Interrupt Priority registers allow the user to select one of two priority levels for each interrupt. An interrupt of a high priority may interrupt the service routine of a low priority interrupt, and if two interrupts of different priority occur at the same time, the higher level interrupt will be serviced first. An interrupt cannot be interrupted by another interrupt of the same priority level. If two interrupts of the same priority level occur simultaneously, a polling sequence is observed as shown in Table XXVI.

Table XXVI. Priority within an Interrupt Level

Source

Priority

Description

 

 

 

 

PSMI

1

(Highest)

Power Supply Monitor Interrupt

IE0

2

 

External Interrupt 0

ADCI

3

 

ADC Interrupt

TF0

4

 

Timer/Counter 0 Interrupt

IE1

5

 

External Interrupt 1

TF1

6

 

Timer/Counter 1 Interrupt

I2CI + ISPI

7

 

I2C/SPI Interrupt

RI + TI

8

 

Serial Interrupt

TF2 + EXF2

9

(Lowest)

Timer/Counter 2 Interrupt

 

 

 

 

Interrupt Vectors

When an interrupt occurs the program counter is pushed onto the stack and the corresponding interrupt vector address is loaded into the program counter. The interrupt Vector Addresses are shown in the Table XXVII.

Table XXVII. Interrupt Vector Addresses

Source

Vector Address

 

 

IE0

0003 Hex

TF0

000B Hex

IE1

0013 Hex

TF1

001B Hex

RI + TI

0023 Hex

TF2 + EXF2

002B Hex

ADCI

0033 Hex

I2CI + ISPI

003B Hex

PSMI

0043 Hex

 

 

REV. B

–39–

Page 39
Image 39
Analog Devices ADuC812 manual Source Priority Description, Source Vector Address