3xx is the effect that enables automatic portamento. It can be used on any channel except DPCM. xx selects the time it takes to sweep from one note to the next; larger values mean shorter sweep time (i.e. faster portamento). 00 disables portamento. It should be noted that any volume envelope does not reset during portamento. For best results, use instruments with constant volume.
Using this effect on the Konami VRC7 chip will eliminate any retriggering of notes.
C-4 00 F --- D-4 -- - 302 --- -- - ---
C-4 is note, 00 is instrument number, F is volume. Sound will start from C-4 and then pitch will slowly change to D-4.
Portamento example — portamento with same instrument and with additional instrument
- 0.2.2 stable: This effect was split into two separate commands when it was introduced in this version. One was the Fxx, the other Gxx. Fxx was equivalent to nowadays 3xx, with the operand incremented by 1. Gxx was equivalent to 300.
- 0.2.4 stable: Fxx and Gxx were renamed to 1xx and 2xx respectively.
- 0.2.7 stable: 1xx and 2xx were merged to a single effect, the 3xx. All subsequent versions automatically convert obsolete effects into the 3xx while opening an old FTM. The portamento off effect remains unused in the FamiTracker source.