EMU_CHAN_PTRX_PITCHTARGET
emu_wrptr(sc, v->vnum, EMU_CHAN_PTRX_PITCHTARGET, pitch_target);
emu_wrptr(sc, v->vnum, EMU_CHAN_PTRX_PITCHTARGET, 0);
emu_wrptr(sc, v->vnum, EMU_CHAN_PTRX_PITCHTARGET, pitch_target);
emu_wrptr(sc, v->vnum, EMU_CHAN_PTRX_PITCHTARGET, 0);