adding readme

pizero/README

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+
+See the top level README for information on where to find documentation
+for the raspberry pi and the ARM processor inside.  Also find information
+on how to load and run these programs.
+
+These examples are for the pi zero, see other directories for other
+flavors of raspberry pi.  The raspberry pi family is more similar than
+different, but I have decided it is easier to manage by grouping the
+examples by board type.
+
+The pi zero is similar to the original pi but overclocked and they
+removed much of the stuff on the board to get things to make it smaller
+and significantly lower cost.  I think this was a direct response to the
+getchip.com product.  I wonder if they will actually continue production.
+
+My preferred way to run examples is to use my bootloader07 kernel.img on
+the board with an ftdi usb to uart board or cable.  I also solder a
+momentary pushbutton on the RUN pins, which is basically a board reset.
+There are ways to do this without soldering, pins you can push in rather
+than solder.
+
+Once the sd card is in with bootloader07, press reset, download the
+intel hex (.hex) version of the program I want to run. Press 'g' to go.
+Repeat as necessary.
+
+Or you can copy the blinker01.bin file to the kernel.img file on your
+sd card, replace the sd card and turn the power on.