W78IRD2 Datasheet, PDF (32/76 Pages) Winbond – 8-BIT MICROCONTROLLER

W78IRD2
8. INTERRUPTS
This section provides more information about external interrupts INT2 and INT3 and provides an
overview of interrupt priority levels and polling sequences.
8.1 External Interrupts 2 and 3
The W78IRD2 offers two additional external interrupts, INT2 and INT3 , similar to external interrupts
INT0 and INT1 in the standard 80C52. These interrupts are configured by the XICON (External
Interrupt Control) register, which is not a standard register in the 80C52. Its address is 0C0H. XICON is
bit-addressable; for example, "SETB 0C2H" sets the EX2 bit of XICON.
8.2 Interrupt Priority
Each interrupt has one of four priority levels in the W78IRD2, as shown below.
Four-level interrupt priority
PRIORITY BITS
IPH.X
IP.X
0
0
0
1
1
0
1
1
INTERRUPT PRIORITY LEVEL
Level 0 (lowest priority)
Level 1
Level 2
Level 3 (highest priority)
Interrupts with the same priority level are polled in the sequence indicated below.
Nine-source interrupt information
INTERRUPT SOURCE
POLLING
SEQUENCE WITHIN
PRIORITY LEVEL
External Interrupt 0
0 (highest)
Timer/Counter 0
1
External Interrupt 1
2
Timer/Counter 1
3
Programmable
Counter Array
4
Serial Port
5
Timer/Counter 2
6
External Interrupt 2
7
External Interrupt 3
8 (lowest)
ENABLE
REQUIRED
SETTINGS
IE.0
IE.1
IE.2
IE.3
IE.6
IE.4
IE.5
XICON.2
XICON.6
INTERRUPT TYPE
EDGE/LEVEL
TCON.0
-
TCON.2
-
-
-
-
XICON.0
XICON.3
VECTOR
ADDRESS
03H
0BH
13H
1BH
33H
23H
2BH
33H
3BH
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