7:5

0h

WO

Rotate and EOI Codes (REOI)

R, SL, EOI - These three bits control the Rotate and End of Interrupt modes and combinations of the two. A chart of these combinations is listed above under the bit definition.
000 Rotate in Auto EOI Mode (Clear)
001 Non-specific EOI command
010 No Operation
011 *Specific EOI Command
100 Rotate in Auto EOI Mode (Set)
101 Rotate on Non-Specific EOI Command
110 *Set Priority Command
111 *Rotate on Specific EOI Command
*L0 - L2 Are Used

4:3

0h

WO

OCW2 Select (O2S)

When selecting OCW2, bits 4:3 = 00

2:0

0h

WO

Interrupt Level Select (L2, L1, L0) (ILSLT)

L2, L1, and L0 determine the interrupt level acted upon when the SL bit is active. A simple binary code, outlined above, selects the channel for the command to act upon. When the SL bit is inactive, these bits do not have a defined function, programming L2, L1 and L0 to 0 is sufficient in this case.