OTSM is fixed. (OP updated) and is working perfectly on a TAv1 17mm light. I don't see any reason this shouldn't become the default setup for these lights. It's just so much better than OTC. As this TAv1-OTSM build is now really (was always meant to be) the flagship HD build, maybe I need a new name for it.
Below are some details about how to build it, also found in the Manual and the OP. In the end this worked so well that it's likely possible to cut some corners, like use cheaper ceramic caps. Personally I probably just wouldn't, but it may work fine.
VIII.1 Parts and build for tested TAv1 board
OTSM is working better and better, but getting it there required a combination
of software work and the best parts. It may be possible now to use cheaper or
lesser parts since OTSM performs a little better than needed with these, but
these are tested and work.
MCU:
It's required to have BODS support for the mcu (see theory below). From page 36
of the manual this requires:
• ATtiny25, revision E, and newer
• ATtiny45, revision D, and newer
• ATtiny85, revision C, and newer
[This note not in manual yet: Revision letter is lower left most letter on bottom of Attiny 25. I forgot on attiny 45 where it is, might be on top.]
The spec for OTSM also requires V version (10Mhz, low voltage version) chips.
You might get by without it, but it won't work as well and may cause
corruption.
Unfortunately most ATtiny 85s reported off the shelf have been revion B, for
the past many years even. They don't work. So far Attiny25, attiny25V,
attiny45 and attiny45 v's where reports exist on this, have been of recent
enough version. Of course attiny25V is available in the smaller footprint and
fits 17mm TAv1 boards. At the time of this writing all HD features including
OTSM can fit on an attiny25.
Diode part number: RB751V40T1G
http://www.onsemi.com/pub/Collateral/RB751V40T1-D.PDF
This is the MCU protection diode. It isolates voltage from the C2 cap that
powers the MCU while input power is down. It was chosen for its low leakage
even at high temperatures. Leakage below 1 or 2 uA is probably fine.
C2 cap (powers MCU during off time, quality counts here)
Cap part number: 298D476X0010P2T
http://www.vishay.com/docs/40065/298d298w.pdf
This cap was chosen to get the most capacitance in an 0805 possible and because
Tantalum does not suffer from DC bias de-rating or temperature fluctuation.
Capacitance this high (47uF) in an 0805 are all low voltage. For Ceramic if
the DC offset is more than about 1/3 of the rated voltage the capacitance
starts to drop, some times a bunch. This cap does have a large tolerance
though unfortunately.
Voltage divider:
Tested with R1 of 1K and R2 of 3.3K R1 should be no more than about 1/3 of R2,
but this ratio should be ideal for OTSM performance in a 1S light (but only in
a 1S light). Lower values can improve OTSM performance, at the expense of
higher mood mode drain. If you use lower quality caps or diode, you can try to
add a bleeder of about 500ohm to gain a little advantage on off time, not much.
OTC:
None, unpopulated.
C1: 1uF (see TA instructions for part numbers)
For all other parts, see the Texas Avenger instructions.