1  This directory contains the Optiboot small bootloader for AVR
 2  microcontrollers, somewhat modified specifically for the Arduino
 3  environment.
 4  
 5  Optiboot is more fully described here: http://code.google.com/p/optiboot/
 6  and is the work of Peter Knight (aka Cathedrow), building on work of Jason P
 7  Kyle, Spiff, and Ladyada.  Arduino-specific modification are by Bill
 8  Westfield (aka WestfW)
 9  
10  Arduino-specific issues are tracked as part of the Arduino project
11  at http://code.google.com/p/arduino
12  
13  
14  ------------------------------------------------------------
15  Building optiboot for Arduino.
16  
17  Production builds of optiboot for Arduino are done on a Mac in "unix mode"
18  using CrossPack-AVR-20100115.  CrossPack tracks WINAVR (for windows), which
19  is just a package of avr-gcc and related utilities, so similar builds should
20  work on Windows or Linux systems.
21  
22  One of the Arduino-specific changes is modifications to the makefile to
23  allow building optiboot using only the tools installed as part of the
24  Arduino environment, or the Arduino source development tree.  All three
25  build procedures should yield identical binaries (.hex files) (although
26  this may change if compiler versions drift apart between CrossPack and
27  the Arduino IDE.)
28  
29  
30  Building Optiboot in the Arduino IDE Install.
31  
32  Work in the .../hardware/arduino/bootloaders/optiboot/ and use the
33  "omake <targets>" command, which just generates a command that uses
34  the arduino-included "make" utility with a command like:
35      make OS=windows ENV=arduino <targets>
36  or  make OS=macosx ENV=arduino <targets>
37  On windows, this assumes you're using the windows command shell.  If
38  you're using a cygwin or mingw shell, or have one of those in your
39  path, the build will probably break due to slash vs backslash issues.
40  On a Mac, if you have the developer tools installed, you can use the
41  Apple-supplied version of make.
42  The makefile uses relative paths ("../../../tools/" and such) to find
43  the programs it needs, so you need to work in the existing optiboot
44  directory (or something created at the same "level") for it to work.
45  
46  
47  Building Optiboot in the Arduino Source Development Install.
48  
49  In this case, there is no special shell script, and you're assumed to
50  have "make" installed somewhere in your path.
51  Build the Arduino source ("ant build") to unpack the tools into the
52  expected directory.
53  Work in Arduino/hardware/arduino/bootloaders/optiboot and use
54      make OS=windows ENV=arduinodev <targets>
55  or  make OS=macosx ENV=arduinodev <targets>
56  
57  
58  Programming Chips Using the _isp Targets
59  
60  The CPU targets have corresponding ISP targets that will actuall
61  program the bootloader into a chip. "atmega328_isp" for the atmega328,
62  for example.  These will set the fuses and lock bits as appropriate as
63  well as uploading the bootloader code.
64  
65  The makefiles default to using a USB programmer, but you can use
66  a serial programmer like ArduinoISP by changing the appropriate
67  variables when you invoke make:
68  
69     make ISPTOOL=stk500v1 ISPPORT=/dev/tty.usbserial-A20e1eAN  \
70          ISPSPEED=-b19200 atmega328_isp
71  
72  The "atmega8_isp" target does not currently work, because the mega8
73  doesn't have the "extended" fuse that the generic ISP target wants to
74  pass on to avrdude.  You'll need to run avrdude manually.
75  
76  
77  Standard Targets
78  
79  I've reduced the pre-built and source-version-controlled targets
80  (.hex and .lst files included in the git repository) to just the
81  three basic 16MHz targets: atmega8, atmega16, atmega328.