Update current state of project.

README.md

@@ -1,33 +1,55 @@
-Notes:
+Features already done:
 
-- Could make the clock oscillilator an external module, with the SEQ listening for a clock on the 16-pin IDC connector when nothing is plugged into CLOCK.
+- Internal clock with manual control.
-- A notable issue with this design is the decade counter expects CLOCK to pass 1/2 of V+ (i.e. 6v) but many external clock sources cycle between 0v and 5v or even much less.  
+- Clock in socket with amplifier to handle weaker (<6v) signals
-This can be fixed by increasing the gain on the CLOCK op-amp from 1 to something more decisive, like 3x.  Then a signal as low as 2v could works as an external clock.
+- Clock out socket, with option to send to 16-pin cable when nothing is plugged into it.
-- One idea: add a switch to disable the clock, and a momentary-on button to advance the step manually.  This requires hardware de-bouncing to avoid multiple triggers on each 
+- Manual one-step-forward via momentary push button.
-button push.
+- CV out, with switch for two different ranges (e.g. 0-2.5v / 0-5v)
-- Another idea: trigger (button push or CV) starts the sequence, which plays through exactly once, and then stops? Possibly put a switch between pin 15 and the three-way junction, and a NO switch across that switch… it might be fine, just go between +12v and pin 15 with the NO.  with the bonus that you can push it to reset a continually-running pattern whenever you want
+- Gate out, with probably +12v gates.
-- Could replace step IDs with a 7-segment display with a diode matrix to select segments from each step.
+- Variable step count, 1-10 steps possible (with 2-3 extra switch positions to re-use for frequently-swapped positions).
-- Could add a global/master pitch control/modulation function with a knob and with CV in implement a DC offset via non-inverting op-amp.
+- External reset via socket.
-- A CV in that pauses the clock and keeps current gate open whenever the voltage exceeds a certain threshold (perhaps useful for feedback effects where one sequencer is interacting with another). More of an experimental functionality
+- External reset via momentary push button.
-- Input/Output CV to permit chaining of Unseen Servants. For example, Unseen Servant 1 plays its sequence, then hands off to Unseen Servant 2, which plays its sequence and then hands back to Unseen Servant 1 (or hands of to Unseen servant 3, etc.). A jacked CV out with no return implies a play sequence once function?
+- Play continuously or play once (switch to select mode, then use manual reset button to run once)
+- Pause sequence and resume - a function of the run/stop switch.  Will hold open the gate of the last step and output CV continously while paused.
+- Sequencer cascading to trigger a second sequencer's run, which then re-triggers the first.
+
+More feature ideas:
+- Trigger out - could be done with a capacitor / resistor pair, see Fireball's hard sync input.
+        - But could also be done at the module that requires a trigger-sized pulse on input.
+- Portamento (aka slew rate controller aka glide).
+        - Knob version fairly simple.
+        - CV version maybe possible, but a much bigger circuit.  Haven't found a simple implementation.  Can be done externally with a more complex module, several variations on the classic "Maths" module exist for modifying a CV in complex ways.
+- CV in to pause the sequence.
+
+Probably can't do, or impractical:
+- CV-controlled clock.  Presumably the CV in controls the clock rate?  Possible in the digital realm, or perhaps an external CV-to-pulse-rate module?  Is this even useful?
+- Seven-segment display.  Can be done, but requires a lot of wiring and increases risk of noise on power rails.
+
+Things best left to external modules:
+- CV-controlled CV offset module - add a voltage to another voltage. Useful here for pitching up from a base.
 
 
 
 UI:
   11 potentiometers
-  11 SPDT switches
+  13 SPDT switches (many used as SPST)
+  2 momentary pushbutton switches
   1 rotary switch, 5+ positions
   10 LEDs
-  3 sockets
+  6 sockets
 
 Potentiometers:
 	One potentiometer per step, to set output voltages. (10)
 	One potentiometer for internal clock rate.
 
 Switches:
-	One SPDT switch per step, to enable/disable gate per step. (10)
+	One SPST switch per step, to enable/disable gate per step. (10)
 	One multi-pole rotary switch to set number of steps.  Exact configuration TBD.
-        One SPDT switch to adjust CV output range, switch between 5v and 2.5v max.
+        One SPDT switch to adjust CV output range, switch between 5v and 2.5v max (or whatever is configured).
+        Momentary-normal-off pushbutton to manually step.
+        SPST switch to disable clock (pause).
+        SPST switch to disable reset (run once).
+        Momentary-normal-off pushbutton to manually reset.
 	
 LEDs:
 	One per step, to indicate current step.  (10)
@@ -35,6 +57,8 @@ LEDs:
 Sockets:
 	CLOCK in
         CLOCK out
-        RESET in
+        RESET / CASCADE in
-	GATE out
+	RESET / CASCADE out
+        GATE out
 	CV out
+