The first offering of a new generation of BLHeli ESCs.  Designed to bring high performance through hardware PWM and the Silabs Busybee line of microprocessors.  Stated benefits are more throttle resolution, smoother response, higher RPM ability and automatic detection of OneShot 125, OneShot 42 and Multishot protocols.

Rated for 2S-4S
30A continous, 40A burst
dimensions
cm battery wires, cm signal leads
weight 

SSKaug stated the features of the new BLHeli_S program in the above thread as:

"BLHeli_S is an improved version of the base BLHeli code.

BLHeli_S delivers a throttle response that is Smooth as Silk, and the main factor contributing to this, is that it uses hardware to generate motor PWM. Two MCUs support this for BLHeli_S, namely the BusyBee1 at 24MHz (EFM8BB10F8) and the BusyBee2 at 48MHz (EFM8BB21F16).

BLHeli_S will have the same good Sync holding properties as base BLHeli. Maybe even better.

BLHeli_S generally does Startup better than base BLHeli.

BLHeli_S does damped light. Only.

BLHeli_S has motor PWM that is Synchronous to the MCU master clock, as it is generated by hardware. This makes the motor Silent.

BLHeli_S has very Small throttle Steps. The resolution varies between hardware configurations (MCU clock speed and driver type), and is between a nominal 512 steps and 2048 steps.

BLHeli_S supports very high motor Speeds. A BB1 MCU will support 350k erpm, and the limit of the BB2 is not yet known, so the code is set to limit at 500k erpm.

BLHeli_S supports regular 1-2ms input signal, as well as Oneshot125, Oneshot42 and Multishot. Autodetected when the ESC sees an input signal.