MT-DB-U4
User Guide
CDC Bootloader (Arduino/AVRDUDE)
CDC Bootloader (Arduino/AVRDUDE)
CDC Serial Driver
The CDC Serial driver allows the board to appear as a COM port. The driver itself is included
with Windows, but an .inf file is needed to configure it. Download the .inf file from
https://www.mattairtech.com/software/MattairTech_CDC_Driver_Signed.zip
. Note that
Windows Vista 64bit, Windows 7 64bit and Windows 8 require the signed driver. You may need to
rename the file so that it has the inf extension. Next, plug in the board with the jumper removed.
Windows will then prompt you for the MattairTech CDC Serial driver. Point the installer to the directory
where you downloaded the driver and install, ignoring any warnings. Once the driver is loaded, the
device will appear as the MattairTech CDC Serial device using a COM port in the device manager.
If you wish, doubleclick on the CDC Serial device entry in the device manager to configure the
driver. Nothing on the port settings tab needs to be changed. We are using a virtual COM port so the
settings are ignored. The baud rate will always be as fast as possible. On the advanced tab, you can
adjust the FIFO buffer sizes. If you experience any buffering problems (ie: a delayed response to user
input), then change both buffer sizes to 1.
CDC Bootloader
The CDC bootloader uses the AVR109 protocol, and can be used withing the Arduino
environment, or directly with AVRDUDE. Version 130410 or above is required to support the auto
reset feature (note that several boards that were shipped before 130626 still have the old bootloader).
If using a terminal emulator, you must first disconnect before running the bootloader. The bootloader
enters programming mode only if the jumper is installed, even when using Arduino autoreset. The
one exception is when the FLASH is empty. Even with the jumper installed, programming mode will
NOT be entered if the reset was from the watchdog timer. The one exception to this is when the boot
key is enabled and the key matches. The key will match when the Arduino IDE autoresets the board
to enter bootloader programming mode. The key is needed because the Arduino core part of the
firmware, which listens for the IDE autoreset signal, uses a watchdog reset to enter the bootloader.
This way, the user application can make use of the watchdog timer. The bootloader will jump to the
user application at the end of FLASH programming. Other operations with AVRDUDE, like writing the
EEPROM, will not trigger this. Just press reset to get back to the bootloader (as long as the jumper is
installed).
May 2, 2014 UPDATE:
Version 140502:
•
Added #define ARDUINO_MODE to AppConfig.h.
This eliminates the requirement for the
jumper to be installed.
Arduino users should now always leave the jumper off. If you cannot
enter the bootloader (ie: sketch compiled with USB_AUTORESET_DISABLED), you can force
the bootloader by installing the jumper (be sure to reselect the COM port).
December 30, 2015
25
http://www.mattairtech.com/
