I've been working on an enhanced version of the GT_DEMO Phaser code.

I really don't know DSP and this is the first program I've done for the FV-1. I just beat / hacked it into submission, not really knowing what I was doing.

Iâ€™ve now got a great sounding phaser with LFO, Depth / Manual, and # of stages (4,6,8,10). Iâ€™ve decided to give back to the Spin community and post the finished code (copy attached).

BTW â€“ it took every last bloody program line!!!!

Enjoy

Doug

Code: Select all

```
;Slocum Phase shifter (From GA_DEMO - mods by Doug Slocum 10/20/2017)
; Uses every last bloody program line!
;Pot0 = Phase rate (manual if fully CCW)
;Pot1 = Sweep width (or manual)
;Pot2 = Num of Stages (4,6,8,10)
;register equates:
equ mono reg0
equ lp1 reg1
equ lp2 reg2
equ phase reg3
equ p1 reg4
equ p2 reg5
equ p3 reg6
equ p4 reg7
equ p5 reg8
equ p6 reg9
equ p7 reg10
equ p8 reg11
equ p9 reg12
equ p10 reg13
equ temp reg14
equ temp1 reg15
;clear registers and initialize LFOs:
skp run,endclr
wrax lp1,0
wrax lp2,0
wlds sin0,12,100 ;sin0 used for phaser operations
wlds sin1,0,32767 ;sin1 used for LFO
endclr:
;sum inputs to mono:
rdax adcl, 0.5
rdax adcr, 0.5
wrax mono, 0
;Do phase shifter from sin1
; Manual or LFO mode test
ldax pot0 ;read pot0, if it's zero then accumulator will be zero, else it will be positive
skp zro, MANUAL ;if zero, then skip to MANUAL otherwise do LFO stuff
;LFO stuff
rdax pot0, 1
mulx pot0
sof 0.12, 0.003
wrax sin1_rate, 0
cho rdal, sin1 ;read sin1 as +/-1
sof 0.5,0.5 ;make positive only sin ranges 0 to 1
log 0.5,0
exp 1,0 ;square root function
sof 1,-0.5 ;make +/-0.5
sof 1.999,0 ;make +/-1 again
mulx pot1 ;pot1 controls phaser depth
sof 0.26,0.72
skp gez, PHASER ;accumulator will always be positive so skip to PHASER:
MANUAL:
rdax pot1, 1
mulx pot1 ;multiply by pot1 for variable range
sof -.999,.999
log 0.9, 0
exp 1,0
PHASER:
wrax phase,0 ;write to modulation register
rdax mono, 1/64 ;input to phase shift network
wrax temp1, 0 ; save it away
; pot ship routines for selecting number of stages
rdax pot2, 1
and %01100000_00000000_00000000 ;mask off only 2 bits, leaving only 4 possibilities
skp zro,STAGES4 ;if zero, the skip over other code to reverb1
sof 1,-0.25 ;subtract 1/4
skp zro,STAGES6 ;if zero, skip over other code to reverb2
sof 1,-0.25 ;subtract 1/4
skp zro,STAGES8 ;if zero, skip over other code to reverb3
clr ;clear the accumulator, there's 1/4 left in it!
STAGES10:
rdax p1,1
wrax temp,1
mulx phase
rdax temp1,1
wrax p1,-1
mulx phase
rdax temp,1
wrax temp1,0
rdax p2,1
wrax temp,1
mulx phase
rdax temp1,1
wrax p2,-1
mulx phase
rdax temp,1
wrax temp1,0
STAGES8:
rdax p3,1
wrax temp,1
mulx phase
rdax temp1,1
wrax p3,-1
mulx phase
rdax temp,1
wrax temp1,0
rdax p4,1
wrax temp,1
mulx phase
rdax temp1,1
wrax p4,-1
mulx phase
rdax temp,1
wrax temp1,0
STAGES6:
rdax p5,1
wrax temp,1
mulx phase
rdax temp1,1
wrax p5,-1
mulx phase
rdax temp,1
wrax temp1,0
rdax p6,1
wrax temp,1
mulx phase
rdax temp1,1
wrax p6,-1
mulx phase
rdax temp,1
wrax temp1,0
STAGES4:
rdax p7,1
wrax temp,1
mulx phase
rdax temp1,1
wrax p7,-1
mulx phase
rdax temp,1
wrax temp1,0
rdax p8,1
wrax temp,1
mulx phase
rdax temp1,1
wrax p8,-1
mulx phase
rdax temp,1
wrax temp1,0
rdax p9,1
wrax temp,1
mulx phase
rdax temp1,1
wrax p9,-1
mulx phase
rdax temp,1
wrax temp1,0
rdax p10,1
wrax temp,1
mulx phase
rdax temp1,1
wrax p10,-1
mulx phase
rdax temp,1
sof -2,0
sof -2,0
sof -2,0
sof -2,0
sof -2,0
sof -2,0 ;output of phase shifter in acc
rdax mono,1
wrax dacl,1
sof 1,-0.04
wrax dacr,0
```