Razor IMU Bootloader Issues

After connecting the Razor 9DOF IMU to the Arduino IDE and attempting the upload the code to the board, the following errors were displayed:

avrdude: stk500_getsync(): not in sync: resp=0x72
avrdude: stk500_disable(): protocol error, expect=0x14, resp=0x72

The board was connected correctly to the computer (since we were reading values output from the sample code pre-loaded onto the chip) and the IDE settings were correct. The correct COM port as well as the correct board (Arduino Pro or Pro Mini (3.3V, 8Mhz) w/Atmega328) were selected.

So after several hours of searching online and looking at other posts/replies regarding this type of issue (such as resetting the board, updating the FTDI drivers, etc), it was mentioned that it may be possible that either the Arduino Bootloader was the wrong version (since SparkFun just changed these boards from the Atmega168 to the Atmega328) or even the Bootloader was corrupted. With these in mind, we tracked down a programmer to try re-burning the Bootloader to the chip.


We weren't able to find an ISP programmer (any from the list in the Arduino IDE, such as the AVRISP or AVR ISP mkII), however we were able to find a AVR JTAGICE mkII programmer. This programmer is able to program through either the JTAG or ISP pins, which is great since the only connections available on the board are Serial and ISP/SPI. Since this programmer is incompatible with the Arduino IDE, we had to use AVRStudio4. Here are the steps we took to re-burning the Arduino Bootloader and getting the Arduino IDE to communicate with the chip:

1. Connected the programmer to the computer with the USB cable (and made sure that the computer had the correct drivers for it).
2. Connected the programmer to the board. After soldering pin headers to the 6-pin ISP/SPI connection, the squid breakout cable (which allows for each of the 10 JTAG cables to be connected individually) was connected using the following websites: JTAGICE mkII (for the programmer connections) and Razor 9DOF IMU Schematic (for the Razor ISP/SPI connections).
3. In AVRstudio, click "Tools" and then "Program AVR".
4. In the "Main" tab, change the device to "Atmega328p" and the programming mode to "ISP".
   
5. In ISP settings, we used 500kHz since the board has a 8MHz clock (ISP requires something under 1/4 the system clock for any board running below 12 MHz. 8/4 -> anything under 2MHz). We chose this just to stay on the safe side.
6. Click "Read Signature". We got a long hex string back (in the box under device name). This is a very good sign, since it means that we are getting data back from the board.
7. In the "Program" tab under "Flash", find the bootloader (this hex file is located in the Arduino folder so for us it was under arduino-0018\hardware\arduino\bootloaders\atmega). We used the ATmegaBOOT_168_atmega328_pro_8MHz.hex (several posts we found indicated that this was what should be used on this board).
8. Click "Program". The Razor board as well as the Tx and Rx pins on our FTDI board lit up as the data was sent and the new Bootloader was burning onto the chip. We didn't see any errors listed at the bottom of the screen, but we clicked "Verify" to make sure.

After we went through these steps, we were able to upload the AHRS code on the board using the Arduino IDE without any problems.