README: add introduction

README.md

@@ -1,4 +1,23 @@
-# Build
+# Bare-metal Rust on Zynq-7000
+
+Supported features:
+
+* Clocking setup
+* UART
+* SDRAM setup
+* Ethernet with smoltcp and async-await on TCP sockets
+* SD card
+* PL programming and startup
+* Pure Rust SZL first-stage bootloader, with SD boot and netboot
+* Control of second CPU core and message passing, with async-await support
+
+
+Supported boards:
+ * ZC706
+ * Red Pitaya (note: SDRAM issues, worked around using `ps7_init`)
+ * Cora Z7-10 (note: SDRAM issues)
+
+## Build
 
 ```shell
 nix-shell --command "cargo xbuild --release -p experiments"
@@ -6,9 +25,9 @@ nix-shell --command "cargo xbuild --release -p experiments"
 
 Currently the ELF output is placed at `target/armv7-none-eabihf/release/experiments`
 
-# Debug
+## Debug
 
-## Running on the ZC706
+### Running on the ZC706
 
 ```shell
 nix-shell --command "cargo xbuild --release -p experiments"
@@ -16,7 +35,7 @@ cd openocd
 openocd -f zc706.cfg
 ```
 
-## Running on the Cora Z7-10
+### Running on the Cora Z7-10
 
 ```shell
 nix-shell --command "cd experiments && cargo xbuild --release --no-default-features --features=target_cora_z7_10"
@@ -24,7 +43,7 @@ cd openocd
 openocd -f cora-z7-10.cfg
 ```
 
-## Loading a bitstream into volatile memory
+### Loading a bitstream into volatile memory
 
 ```shell
 openocd -f zc706.cfg -c "pld load 0 blinker_migen.bit; exit"