EVAL-ADUC836QS AD [Analog Devices], EVAL-ADUC836QS Datasheet - Page 62

• Manufacturer Part Number: EVAL-ADUC836QS
• Description: MicroConverter, Dual 16-Bit ADCs with Embedded 62 kB Flash MCU
• Manufacturer: AD [Analog Devices]

Interrupt Priority
The Interrupt Enable registers are written by the user to enable
individual interrupt sources, while the Interrupt Priority reg is ters
allow the user to select one of two priority levels for each inter-
rupt. An interrupt of a high priority may interrupt the ser vice
routine of a low priority interrupt, and if two interrupts of differ-
ent priority occur at the same time, the higher level in ter rupt will
be serviced fi rst. 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 used to
determine which interrupt is serviced fi rst. The poll ing sequence
is shown in Table XXXVIII.
Source
PSMI
WDS
IE0
RDY0/RDY1
TF0
IE1
TF1
ISPI/I2CI
RI + TI
TF2 + EXF2
TII
ADuC836
Table XXXVIII. Priority within an Interrupt Level
Priority
1 (Highest)
2
3
4
5
6
7
8
9
10
11 (Lowest)
Description
Power Supply Monitor In ter rupt
Watchdog Interrupt
External Interrupt 0
ADC Interrupt
Timer/Counter 0 Interrupt
External Interrupt 1
Timer/Counter 1 Interrupt
SPI Interrupt
Serial Interrupt
Timer/Counter 2 Interrupt
Time Interval Counter Interrupt
–62–
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 Table XXXIX.
*The watchdog can be confi gured to generate an interrupt instead of
Source
IE0
TF0
IE1
TF1
RI + TI
TF2 + EXF2
RDY0/RDY1 (ADC)
ISPI/I2CI
PSMI
TII
WDS (WDIR = 1)*
a reset when it times out. This is used for logging errors or examining
the internal status of the microcontroller core to understand, from
a software debug point of view, why a watchdog timeout occurred.
The watchdog interrupt is slightly different from the normal inter-
rupts in that its priority level is always set to 1 and it is not possible
to disable the interrupt via the global disable bit (EA) in the IE SFR.
This is done to ensure that the interrupt will always be responded
to if a watchdog timeout occurs. The watchdog will only produce an
interrupt if the watchdog timeout is greater than zero.
Table XXXIX. Interrupt Vector Addresses
Vector Address
0003H
000BH
0013H
001BH
0023H
002BH
0033H
003BH
0043H
0053H
005BH
REV. 0