README: update

README.md

@@ -1,3 +1,31 @@
 # Stabilizer Firmware
 
-Hardware is at: https://github.com/sinara-hw/Stabilizer
+## Features
+
+* dual channel
+* SPI ADC
+* SPI DAC
+* fixed AFE gains
+* 500 kHz rate, timed
+* < 2 µs latency, unmatched
+* f32 IIR math
+* generic biquad (second order) IIR filter
+* anti-windup
+* derivative kick avoidance
+* configurable output limits
+
+## Hardware
+
+See https://github.com/sinara-hw/Stabilizer
+
+## Minimal bootstrapping documentation
+
+* Clone or download this
+* Get a recent openocd, a JTAG adapter ("st-link" or some clone) and
+  everything connected and permissions setup
+* Get a multiarch `gdb` (or a cross arm gdb and edit `.cargo/config` accordingly)
+* Get [rustup](https://rustup.rs/)
+* `rustup override add nightly`
+* `rustup target add thumbv7em-none-eabihf`
+* `openocd -f stabilizer.cfg` and leave it running
+* `cargo run --release`