Specifications

Interrupt Controller (V40)
IIW1 and IIW2
Interrupt Initialization Words 1 (IIW1) and 2 (IIW2) are required
for ICU initialization. The IIW1 register, shown in Figure 8-3, is
divided into two fields labeled II4 (Interrupt Initialization 4) and
LEV (Level). The II4 bit selects whether or not the IIW4 register
is to be programmed. If II4 is set to a logical 1, the ICU expects
IIW4 to be written as part of the initialization. The LEV bit of
IIW1 selects between level- or edge-triggered interrupt request
inputs. Setting LEV to a logical 1 selects level-triggered inputs,
while a logical 0 selects edge-triggered.
IIW1
Address: Base + 0
Access: Write
76543210
II4
Writes IIW4
0 IIW4 not required
1 IIW4 required
1—LEV
Level-Triggered Mode
0 Edge-triggered
1 Level-triggered
1———
Figure 8–3. Interrupt Initialization Word 1.
8-9