Improve Mac and Windows instructions

openocd/README.md

@@ -9,10 +9,18 @@ flashing programs and bootloaders.
 
 On Linux, TODO.
 
-On Mac, using [Homebrew](https://brew.sh/): `brew install openocd`.
-
-On Windows, there is no package manager. Untested: there are binaries
-[here](https://gnutoolchains.com/arm-eabi/openocd/).
+On Mac, using [Homebrew](https://brew.sh/): `brew install openocd`. As of Dec. 5, 2019, this gives
+you version 0.10.0, which supports ATSAMD11, but not SAMD51. So you if you want to use the latter
+chip, you might need to build from source.
+
+On Windows, there is no package manager. But you can grab binaries
+[here](https://gnutoolchains.com/arm-eabi/openocd/). Once you've downloaded the latest release,
+unpack it and put it wherever you want it to live. The important file is `bin/openocd`. You can
+either type out the full path whenever you want to run it (e.g. something like `C:\\Program
+Files\openocd\bin\openocd`, instead of just `openocd`), or you can add the `bin` dir to your path.
+(See
+[here](https://www.howtogeek.com/118594/how-to-edit-your-system-path-for-easy-command-line-access/)
+or Google elsewhere for instructions on adding directories to your path.)
 
 ### From Source