boot430 0.91

 October 2013 v0.91a, add "hid mouse" example build along w/ bootloader function
 October 2013 v0.91, stability improvements
 chris chung (simpleavr) Feburary 2013 v0.90

CREDITS:

based on works from;
. Matthias Koch, Mecrimus-B, provides orginal assembler usb implementation
. Kevin Timmerman, oPossum, provides TI ccs v4 translation on usb implementation
. David Grimbichler, theprophet, enhance transfer timing and correct detail message formats
. Chris Chung, simpleavr, www.simpleavr.com, provides mspgcc translation
  and bootloader application logic
. Christian Starkjohann, OBJECTIVE DEVELOPMENT Software GmbH, www.obdev.at
  reference hid bootloader project, commandline code framework used in this project

  please see License.txt for licensing

DESCRIPTION:

. boot430 is usb bootloader for certain (8k and 16k) msp430g2xxx value line devices.
. based on bbusb (for bit-bang usb), a v-usb like low-speed usb implementaion on msp430
. requires a minimal component circuit and is very breadboard friendly.
. can be used for other usb implementations, by replacing bbusb_prototcol.c and main()
. there are many alternate h/w hookups, research "v-usb 3.3v"
. compile w/ mspgcc, works on linux and windows w/ cygwin
. requires libusb
* (new v0.91a) add new Makefile.hid to build a simple hid mouse instead of a complex bootloader

SCHEMATIC:
                  MSP430G2xxx                   Vcc (3.3v)
         Vcc   -----------------                 /|\
         /|\  |                 |                 |       ___
          |   |                 |                 |      /   \ LP2950AC3.3
          |   |                 | Vcc             +-----o__o__o------
         .-.  |                 | /|\             |    Out |  In    |
    4.7k | |  |                 |  |              |        |        |
         | |  |                 |  |              --| |----+---| |--+
         .-.  |                 | .-.               10uF   |  0.1uF |
          |   |                 | | | 1.5k                 |        ----------o Vusb (5v)
          ----|RST              | | |                      | 
          ----|P2.6             | .-.                      -------------------o Gnd
          |   |                 |  |
    led  \ /  |             P1.1|--+-[ 68ohm ]--------------------------------o D-
         ---  |                 |
          |   |             P1.0|----[ 68ohm ]--------------------------------o D+
          ----|P2.7             |

    * led is optional, if used, better attach a series resistor of a few hundred ohms for reliability
	* LP2950 can be replaced by similar 3.3v LDO regulator (try 3.6v LDO to improve reliability)

FEATURES:

. occupies 2.4k flash space
. requires no external crystal, timer sychronize via usb sync frame
. v-usb like circuitry, BOM (68ohm x 2, 1.5k, 4.7k, LP2950AC3.3, 10uF, 0.1uF, led)
. supports 8k and 16k msp430g2xxx value line devices
. bootloader checks for D- pull-up and usb host presence upon bootup

NOTES:
. change MCU= in Makefiles for target device (g2553, g2342 tested)
. commandline contains host side bootloader code
. apps directory contains sample applications to test firmware bootloading

(2013.10.xx)
  . there is no change in bootloader except toogle_syncled() disabled
  . add files and build mechanism for a simple hid mouse application (no bootloader)
  . use Makefile.hid instead of Makefile, sample "hid430.hex" firmware included
  . to build and flash, (1) make -f Makefile.hid, (2) make -f Makefile.hid flash
  . please view and change Makefiles to reflect your device (MMCU)

(2013.10.xx)
  2013.10 changes this v0.91 mainly contributed by David Grimbichler aka "theprophet"

  . David tried v0.90 and had numerous issues
  . had provided various fixes to enable reliability on various platforms
  . implement correct report_id according to usb standards
  . implement a much more reliable timing scheme for data flashing and transfer
  . bootloader is a bit slower but much more reliable
  * if you use a led "heartbeat" blinker between P2.6 and P2.7, be sure to use a resistor
  * if you have a choice, use a 3.6V LDO for better reliability
  * if you need help, find the appropriate thread in 43oh.com forum, most authors frequent that
  * now include binary excutable, Windows apps loader "commandline/boot430load.exe"
  * and bootloader hex firmware "boot430.hex"


(2012.12.xx)
  . it started from a thread post in 43oh.com, look for "bit-bang usb"
  . Macrimus-B posted code on a bit-bang usb implementation for msp430
  . oPossum translate assembler code to TI CCS, w/ simplier C entry points
  . myself translate code into mspgcc, implements this bootloader on top

(2013.02.05)
  . initial checkin