Update a README file

configs/pcduino-a10/README.txt

@@ -327,9 +327,13 @@ Configurations
   can be selected as follow:
 
     cd tools
-    ./configure.sh pcduino-a10/<subdir>
+    tools/configure.sh [OPTIONS] pcduino-a10/<subdir>
     cd -
 
+  Where [OPTIONS] include -l to configure for a Linux host platform and
+  -c means to configure for a Windows Cygwin host platform.  -h will give
+  you the list of all options.
+
   Before building, make sure the PATH environment variable includes the
   correct path to the directory than holds your toolchain binaries.
 

configs/pizero/README.txt

@@ -1,6 +1,22 @@
 README
 ======
 
+  This README file discusses the port of NuttX to the Raspberry Pi Zero.
+  The Raspberry Pi Zero is based on the Broadcom BCM2835 CPU.  This is the
+  same Broadcom chip used in the Raspberry Pi Model A, B, B+, the Compute
+  Module.
+
+STATUS
+======
+
+  2017-10-09:  This is a work in progress.  The port is not complete and
+    will not build to completion.  Missing logic includes:
+
+    - GPIO support,
+    - Peripheral clocking support,
+    - System timer initialization, and
+    - Serial driver.
+
 Basic Setup
 ===========
 
@@ -27,3 +43,51 @@ Basic Setup
   able to do that; my hub would not switch on power until it was enumerated
   by the host (the Raspberry Pi Zero), but then I could not power the Pi
   with the hub because it was not providing power.  Chicken'n'Egg.
+
+NuttX Boot Sequence
+===================
+
+  To be provided.
+
+Configurations
+==============
+
+  Information Common to All Configurations
+  ----------------------------------------
+  Each Raspberry Pi Zero configuration is maintained in a sub-directory
+  and can be selected as follow:
+
+    tools/configure.sh [OPTIONS] pizero/<subdir>
+
+  Where [OPTIONS] include -l to configure for a Linux host platform and
+  -c means to configure for a Windows Cygwin host platform.  -h will give
+  you the list of all options.
+
+  Before building, make sure the PATH environment variable includes the
+  correct path to the directory than holds your toolchain binaries.
+
+  And then build NuttX by simply typing the following.  At the conclusion of
+  the make, the nuttx binary will reside in an ELF file called, simply, nuttx.
+
+    make
+
+  The <subdir> that is provided above as an argument to the tools/configure.sh
+  must be is one of the following.
+
+  NOTES:
+
+  1. These configurations use the mconf-based configuration tool.  To
+    change any of these configurations using that tool, you should:
+
+    a. Build and install the kconfig-mconf tool.  See nuttx/README.txt
+       see additional README.txt files in the NuttX tools repository.
+
+    b. Execute 'make menuconfig' in nuttx/ in order to start the
+       reconfiguration process.
+
+  Configuration Sub-directories
+  -----------------------------
+
+  nsh:
+
+    This simple configuration directory provide the NuttShell (NSH).