4. Interrupt Controller
34
Interrupt Architecture Initialization Registers (ICW1-ICW4)
Each interrupt controller must be initialized before it is used. Initialization consists of
writing two, three, or four initialization commands. The programming sequence for these
registers is given in the "
Interrupt Initialization Programming
" figure below. ICW1, ICW2,
and ICW3 must be programmed during each initialization sequence. ICW4 may or may
not be programmed, as required by the application.
ICW1
BASE A0
BASE A1
ICW2
ICW3
BASE A1
BASE A1
ICW4
ICW1 BIT0=1
NO
YES
INITIALIZATION
COMPLETE
Interrupt Initialization Programming
0
0
7
6
5
4
3
2
1
0
0
1
Register : ICW1
Address: Base+1
Input Trigger
0 Edge Triggered
1 Level triggered
LTIM
0
0
1
Access:Write
Initialization Register ICW1
