- AVR studio (tested with 6.1)
- avrdude (tested with 6.1 built from source, the version in the Debian repositories does /not/ work) The boot loader is in the same repository as the library which is a bit of a mess but it makes it easy to build
start the avr studio shell
cd to lufa/Bootloaders/CDC/
make
the file "BootloaderCDC.hex" should be loaded onto the micro controller
avrdude -c avr109 -p x128a3u -P /dev/ttyACM0 -D -U flash:w:./rom.hex -C ./avrdude.conf
(specifying your avrdude.conf is not necessary if you have replaced the older avrdude.conf)
- Figure out what's wrong with reading the test switch
- Integrate Xbee stuff
#Possible XBee Path
Reference: Xbee 900HB Manual: ftp://ftp1.digi.com/support/documentation/90002173_B.pdf
Bee bootloader project
- maximum packet size with Xbee 900HB is 256. Expressed as global variable in Xbee.py
- refactor things so that escape bits are used (Arduino Xbee library requires escape characters so that way we match it)
- page 57 in documentation
- needs to parse firmware code from multiple packets
Any packet will have this kind of prefix:
| START DELIMITER (0x7E) | LENGTH (MSB) | LENGTH (LSB) | FRAME TYPE (TRANSMIT=0x10) | FRAME ID (want ACK) |
|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 |
Then, there is the actual API frame.
Finally, there is the suffix of the checksum. In python, checksum can be calcualted: (0xFF-sum(i[3:-1])&255)
Note that the API mode we are using implement escape bytes so that we can be compatible with the Xbee-Arduino library. Here is the relevant documentation:
Data bytes that need to be escaped: • 0x7E – Frame Delimiter • 0x7D – Escape • 0x11 – XON • 0x13 – XOFF
Example - Raw serial data frame (before escaping interfering bytes): 0x7E 0x00 0x02 0x23 0x11 0xCB
0x11 needs to be escaped which results in the following frame: 0x7E 0x00 0x02 0x23 0x7D 0x31 0xCB
Note: In the above example, the length of the raw data (excluding the checksum) is 0x0002 and the checksum of the non-escaped data (excluding frame delimiter and length) is calculated as: 0xFF - (0x23 + 0x11) = (0xFF - 0x34) = 0xCB
When the Xbee FRAME TYPE is transmit, then we enter the world of our own custom API.
Byte 5: bit 7: ACK request bit 6-4: Apitronics Frame bit 3-0: MS-half Byte Index
Byte 6: LSB Index
This means that the maximum index is 2**12=4096 which is enough to transmit over 1MB. It also means that the Apitronics Frame set can have at most 8 frames.
| ACK and Index | Index | Actual Data |
|---|---|---|
| 5 | 6 | 7 til end |