Clean up tech notes

docs/tech-notes.md

@@ -70,11 +70,33 @@ Here's what each bit means:
 * 0o13: Cymbal modifier
 * 0o14: Select
 
+Hats
+----
 
-hatAndConstant
---------------
+I guess "hats" are what I would have called "joysticks and dpads".
 
-The HAT switch reports its position like a clock.
+
+### Hat 0: unknown
+
+This doesn't appear to be sent or used.
+
+### Hat 1: guitar analog controls
+
+The X axis is the position of the wammy bar.
+
+The Y axis is the pickup selector.
+I believe this was a 5-position switch on some guitars.
+Only Rock Band 1 seems to use this.
+
+### Hat 2: navigation
+
+Sent by the dpad on the controller,
+as `hatAndConstant`.
+
+Guitars send up/down for the up/down strum buttons.
+Drums send up/down on the blue/yellow cymbal pads.
+
+The position of this digital input is reported in only 3 bits:
 
     7   0   1
 
@@ -102,20 +124,19 @@ Sending these values does not seem to cause problems with my Wii games.
 Product ID (PID)
 ----------------
 
-Nicholas,
-who did the initial work on the guitar,
-suggested that PID 0x0005 would get the sketch working as drums.
-And that was correct:
-this works great on 
-Wii Rock Band 1 and 
-Wii LEGO Rock Band.
+The following USB PIDs are recognized by various things:
 
-But it fails in frustrating ways on
-Wii Rock Band 3:
-the yellow and blue pads don't navigate menus,
-and cymbals aren't detected.
+* 0x0003: XBox Drum
+* 0x0004: Wii Guitar
+* 0x0005: Wii Drums - Rock Band 1
+* 0x3110: Wii Drums - Rock Band 2
 
-The fix was setting the USB PID to 0x3110.
+There are some quirks to note:
+
+* Rock Band 3 won't recognize cymbal hits on PID=0x0005,
+  but the same program with PID=0x3110 works fine.
+* Wii games don't appear to recognized PID=0x0003.
+  Maybe Rock Band 3 does: I didn't test that one.
 
 
 Drum Velocity
@@ -123,7 +144,8 @@ Drum Velocity
 
 I split the 12 "reserved" bytes from Nicholas's 
 `struct InstrumentButtonState`
-into 4 bytes of I-Don't-Know, 4 bytes of velocity,
+into 4 bytes of I-Don't-Know,
+4 bytes of velocity,
 and 4 more bytes of I-Don't-Know.
 Whenever a pad is hit,
 I send 127 on the corresponding velocity.
@@ -134,29 +156,17 @@ and looks only at the velocity values.
 
 None of the Wii games I have
 seem to care what these values are set to.
+Clone Hero also does not care.
 
 
 Clone Hero
 ==========
 
-This controller doesn't have a dpad (currently),
-so we're using 12 buttons to represent the state of 9 inputs.
-Sometimes software is just weird!
+Clone Hero wants Hat 2 up on yellow cymbal hit,
+and Hat 2 down on blue cymbal hit.
 
-Clone Hero has two undocumented CymExt1 and CymExt2 mappings.
-It talks about what they should be set to (on Windows) in the wiki,
-but doesn't explain what they're used for.
-
-It seems that Clone Hero expects the Yellow and Blue cymbals
-to send dpad inputs, in addition to the pad color and cymbal modifier.
-If the controller doesn't send these,
-then every drum pad hit plays that color's drum and cymbal at the same time,
-and every cymbal pad hit does the same thing.
-
-I'm not exactly sure why Clone Hero does this,
-but in any case,
-Mockband sends the right things now,
-so the drum controller should work correctly after you map everything.
+If it doesn't see these while mapping drum pads,
+then hitting any color bad will trigger both drum and cymbal for that color.
 
 
 References