How To Program the Roland TB-303
Part I - Entering The Pitches
OK, here's how to program patterns into the 303. First turn the MODE dial to PATTERN WRITE. This puts the 303 in a step-record mode. (You should only use PATTERN WRITE or TRACK WRITE modes during editing and creating new patterns. Remember to switch back to PATTERN PLAY or TRACK PLAY when you are finished editing.)
Select the PATTERN NUMBER where your pattern will be stored. For example, we will choose pattern location #1 which is the 'C' key (also labeled '1') to the right of the function button. You may choose any of the 16 locations. Your patterns will remain in these memory locations as long as there are working-batteries in the 303.
Lets clear out any information that may already be stored here. Hold down your PATTERN NUMBER button and PATTERN CLEAR simultaneously.
Now enter the Pitch-Mode by pressing the PITCH MODE button.
Now we can enter the notes of our pattern using the 13 pitch buttons. The buttons are laid-out like a one octave keyboard. You will be able to hear the pitches as they are entered. Enter each note for your pattern, one at a time. The note-lengths will be determined in Part II. Later you will see how to transpose notes up and down in Part III.
When you're done press the FUNCTION button to exit pitch mode.
Part II - Entering The Timing
Now we need to create the rhythmic element of our pattern by entering the lengths of each note, such as eighth-notes, quarter-notes, etc... To begin, push TIME MODE to enter the timing mode.
The timing info is entered using combinations of 16th notes, 16th holds, and 16th rests. These keys are also labeled TRANSPOSE DOWN, UP and ACCENT. So lets say we want to enter 2 quarter-notes and 4 eighth-notes, your entry should look like this:
Once you are in TIME MODE, the 303 is waiting for your input for the first position in the 16-note pattern. We want to designate that note as a quarter-note. To do this, hit the  key (also labeled Transpose Down [TD]). Next hit the [o] (Transpose Up [TU]) key three times. This combo of one 16th-note followed by three 16th-holds creates a quarter note. The pitches you entered in Part I will only occur wherever you place a  note. If you hit the [-] (Accent) key in place of the [o] key then you will have entered three rests and your first note will be a true sixteenth note. Becoming creative or being random with these three buttons is the key to finding the types of patterns that made the 303 and Acid-lines famous! Finish off this pattern by pressing the keys:  TD, [o] TU, [o] TU, [o] TU,  TD, [o] TU,  TD, [o] TU,  TD, [o] TU,  TD, [o] TU. This completes our simple measure. Once you've entered all 16 notes of timing info you will automatically return to the FUNCTION MODE.
Part III - Entering Accents and Slides
Now we may want to enter slides, octave transpositions and accents. Hit PITCH MODE to return to the pitch entry mode.
We will scroll through to the pitch where we want to add any slides, accents or transpositions. Press WRITE/NEXT to scroll through the notes. Scroll through your pattern (counting in your head) until you know that the next time you hit the WRITE/NEXT key it will be for the particular note you are planning to edit.
For example, if we wanted to add an ACCENT and SLIDE to the 3rd note (the eighth-note in position 9) in our pattern from above: Press the WRITE/NEXT button two times, and then hold it down for the third time and simultaneously hit the ACCENT and SLIDE keys (their LEDs will light up) to apply them to the third note in our sequence. Do the same wherever you want to add slides, accents, transpose a note up or down.
When you are done with that, hit FUNCTION to leave the pitch mode.
Now you can hit RUN/STOP to hear your pattern. At anytime you can re-enter any of these modes to change the timing, pitches, or effects. Just remember to use the WRITE/NEXT button to scroll through your pitches+effects or your timing info.
GO TO THE TB-303 PAGE.