| otir || 11101101 10110011 || 6/5 || 21/16 (4,5,3,4,5)/(4,5,3,4) || + || + || + || X || + || X || X || X || outi, if b <> 0 then pc -= 2 || I/O Output and Increment, Repeat
|}
=== I/O group ===
{| class="wikitable" style="white-space: nowrap;"
|-
! Instruction !! Opcode !! NOPs !! Cycles !! S !! Z !! 5 !! H !! 3 !! P !! N !! C !! Effect !! Description
|-
| in a,(N) || 11011011 nnnnnnnn || 3 || 11 (4,3,4) || - || - || - || - || - || - || - || - || a := ((N)) ||rowspan=3|I/O Input
|-
| in R,(c) || 11101101 01rrr000 || 4 || 12 (4,4,4) || + || + || + || 0 || + || P || 0 || - || R := ((c))
|-
| in f,(c) || 11101101 01110000 || 4 || 12 (4,4,4) || + || + || + || 0 || + || P || 0 || - || tmp := ((c))
|-
| out (N),a || 11010011 nnnnnnnn || 3 || 11 (4,3,4) || - || - || - || - || - || - || - || - || ((N)) := a ||rowspan=3| I/O Output
|-
| out (c),R || 11101101 01rrr001 || 4 || 12 (4,4,4) || - || - || - || - || - || - || - || - || ((c)) := R
|-
| out (c),0 || 11101101 01110001 || 4 || 12 (4,4,4) || - || - || - || - || - || - || - || - || ((c)) := 0 (255 on CMOS CPU)
|}
Note: The INI instruction has incorrect timing in the official Zilog manual. [https://forums.nesdev.org/viewtopic.php?p=181645f#p181645 Source]
=== Control flow group ===
|}
=== Letter I === {| class="wikitable" style="white-space: nowrap;"|-! Instruction !! Opcode !! NOPs !! Cycles !! S !! Z !! 5 !! H !! 3 !! P !! N !! C !! Effect !! Description|-| in a,(N) || 11011011 nnnnnnnn || 3 || 11 (4,3,4) || - || - || - || - || - || - || - || - || a := ((N)) ||rowspan=3|I/O Input|-| in R,(c) || 11101101 01rrr000 || 4 || 12 (4,4,4) || + || + || + || 0 || + || P || 0 || - || R := ((c))|-| in f,(c) || 11101101 01110000 || 4 || 12 (4,4,4) || + || + || + || 0 || + || P || 0 || - || tmp := ((c))|} Note: The INI instruction has incorrect timing in the official Zilog manual. [https://forums.nesdev.org/viewtopic.php?p=181645f#p181645 Source] === Letter L Load group ===
{| class="wikitable" style="white-space: nowrap;"
|-
| ld sp,I || 11i11101 11111001 || 3 || 10 (4,6) || - || - || - || - || - || - || - || - || sp := I
|}
=== Letter O ===
{| class="wikitable" style="white-space: nowrap;"
|-
! Instruction !! Opcode !! NOPs !! Cycles !! S !! Z !! 5 !! H !! 3 !! P !! N !! C !! Effect !! Description
|-
| out (N),a || 11010011 nnnnnnnn || 3 || 11 (4,3,4) || - || - || - || - || - || - || - || - || ((N)) := a ||rowspan=3| I/O Output
|-
| out (c),R || 11101101 01rrr001 || 4 || 12 (4,4,4) || - || - || - || - || - || - || - || - || ((c)) := R
|-
| out (c),0 || 11101101 01110001 || 4 || 12 (4,4,4) || - || - || - || - || - || - || - || - || ((c)) := 0 (255 on CMOS CPU)
|}