{| class="FCK__ShowTableBorders"
|-
| ''Bit'' || ''Value'' || ''Function''
|-
| 7 || 1 || rowspan="2" | Gate Array function
|-
| 6 || 0
|-
| 5 || - || not used
|-
| 4 || x || Interrupt generation control
|-
| 3 || x | *| 1 =Upper ROM area disable *, 0 =Upper ROM area enable
|-
| 2 || x | *| 1 =Lower ROM area disable *, 0 =Lower ROM area enable
|-
| 1 || x || rowspan="2" | Screen Mode slection
|-
| 0 || x
|}