BeagleBoard Trainer

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Trainer Features:

  • I2C interface(+3.3v or +5v selectable)
  • SPI inteface (+3.3v)
  • GPIO's(+3.3v)
  • Large prototyping area (0.1" x 0.1" matrix with access to power bus)
  • Atmega328 processor (user programmable)
    • Arduino compatible
    • ATmega328 power is +3.3v or +5v selectable
    • Communicate to the ATmega328 via the BeagleBoard's second RS-232 uart

Available from


Trainer Rev-A

Trainer Rev-A Interface

I²C Interface

The Trainer provides an interface to the BeagleBoard's I²C port. The I²C signals are level translated to either +3.3V or +5V (user selectable with a jumper). The I²C signals are located next the the prototyping area.

How to access the I2C bus (from software):

SPI Interface

The Trainer provides an interface the the BeagleBoard's SPI port and the signals are level translated to +3.3V. The SPI signals are located next to the prototyping area.

GPIO Interface

The Trainer provides an interface to several of the BeagleBoard's GPIO signals. The GPIO signals are level translated to +3.3V and are located next to the prototyping area.


The Trainer board provides an AT24C01 serial EEPROM that contains a Vendor ID and a Device ID that the BeagleBoard uses to identify the type of board connected to the expansion header. This information enables the BeagleBoard to auto-configure the pin mux for signals needed by the Trainer. More information can be found on the Beagle Board Pin Mux Page.

ATmega328 (Arduino Hardware Compatible)

An ATmega328 embedded processor is located on the Trainer board that is user programmable. The ATmega328 is hardware compatible with the Arduino and it's I/O signals are available next to the prototyping area. The ATmega328 can be user jumpered to run at either +3.3V or +5V. One of the BeagleBoard's GPIO signals (GPIO 162) controls the ATmega328's power supply and can turn on or off the power to the ATmega328. The ATmega328 can run off it's internal RC oscillator or it also has an external 8.0 Mhz ceramic resonator.

Note: The ATmega328 must be programmed with an external hardware programmer (not included) like the Pocket AVR Programmer or the ATAVRISP2.

avrdude -c usbtiny -p atmega328p -e -u -U lock:w:0x3f:m -U efuse:w:0x05:m -U hfuse:w:0xda:m -U lfuse:w:0xff:m
avrdude -c usbtiny -p atmega328p -U flash:w:ATmegaBOOT_168_atmega328_pro_8MHz.hex -U lock:w:0x0f:m
  • AVR code and Arduino sketches can be uploaded using avrdude on the BeagleBoard:
avrdude -V -F -c stk500v1 -p m328p -P /dev/ttyS1 -b 57600 -U flash:w:main.hex
  • AVR code and Arduino sketches can be uploaded using avrgal on the BeagleBoard:
avrgal main.hex

Prototyping / Breakout Area

  • provides a prototyping / breakout area with a standard 0.1" x 0.1" spacing matrix
  • Access to BeagleBoard's level translated signals
  • Access to the ATmega328's I/O pins

PC Board Test Point Locations

Trainer Rev-A

PC Board Silkscreen Errata

There are errors on four silkscreen labels on the Trainer Rev-A board. The silkscreen for the signals: GP135, GP134, GP133, and GP132 are mislabeled. The correct labels are indicated on the following image:

Trainer Errata Rev-A

Note: Trainer Rev-B has fixed these errors.

Soldering BeagleBoard's Expansion Header

This is a quick guide showing you how to solder the 2x14 Header into the BeagleBoard’s Expansion connector (J3).

Zippy2-expansion connector1.jpg

Insert the 2x14 Header’s SHORT PINS from the back side of the BeagleBoard into the BeagleBoard’s expansion connector (J3).

Zippy2-expansion connector2.jpg

Position the 2x14 Header so the LONG PINS are on the BACK SIDE of the BeagleBoard.

Zippy2-expansion connector3.jpg

Solder the SHORT PINS of the 2x14 Header from the TOP SIDE of the BeagleBoard.

Attaching to the BeagleBoard

Zippy2-expansion connector7.jpg

Attach the four board spacers with the screws provided.

Zippy2-expansion connector4.jpg

Connect the expansion board onto the BACK SIDE of the BeagleBoard by mating with the 2x14 Header you just soldered. Make sure all of the pins align correctly.

Zippy2-expansion connector5.jpg

Continue pushing the two boards together until the connectors mate together.

Zippy2-expansion connector6.jpg

Attach the male standoffs as shown.

Zippy2-expansion connector8.jpg

Creating a bootable SD card in Ubuntu

This guide will demonstate how to create a dual-partition SD card for the BeagleBoard/Trainer board combination to boot Linux from the first partition and have the root file system located on the second partition.

This guide covers the same procedure as SDCard setup and LinuxBootDiskFormat.

This guide will use a 2GB SD card for all examples.

Determine which device the SD Card Reader is on your system

Insert the SD Card into the SD Card Reader reader on your Linux PC. Then determine which device it is on your system:

dmesg | tail
[2079456.496092] sd 34:0:0:0: [sdb] Mode Sense: 03 00 00 00
[2079456.496096] sd 34:0:0:0: [sdb] Assuming drive cache: write through
[2079456.513743] sd 34:0:0:0: [sdb] Assuming drive cache: write through
[2079456.513751]  sdb: sdb1
[2079456.529193] sd 34:0:0:0: [sdb] Assuming drive cache: write through
[2079456.529201] sd 34:0:0:0: [sdb] Attached SCSI removable disk

In this case it shows up as /dev/sdb (note sdb insite the square brackets above).

Check to see if the automounter has mounted the SD Card:

df -h
Filesystem            Size  Used Avail Use% Mounted on
...                   1.8G     0  1.8G   0% /lib/init/rw
/dev/sdb1             1.9G     0  1.9G   0% /media/6262-9331

If mounted, unmount the SD card

umount /media/6262-9331

Start fdisk:

sudo fdisk /dev/sdb

Print the partition record:

  Command (m for help): p

  Disk /dev/sdb: 1967 MB, 1967128576 bytes
  57 heads, 56 sectors/track, 1203 cylinders
  Units = cylinders of 3192 * 512 = 1634304 bytes
  Disk identifier: 0x00000000

  Device Boot      Start         End      Blocks   Id  System
  /dev/sdb1            1        1204     1920955+   6  FAT16

Note card size in bytes listed above (in this example: 1967128576). Write this number down, it will be needed later below.

Delete any partitions that are already on the SD card

 Command (m for help): d
 Selected partition 1

Set the Geometry of the SD Card

Go into "Expert mode":

 Command (m for help): x

Now we want to set the geometry to 255 heads, 63 sectors and calculate the number of cylinders required for the particular SD card you are using:

  Expert command (m for help): h
  Number of heads (1-256, default 57): 255

  Expert command (m for help): s
  Number of sectors (1-63, default 56): 63
  Warning: setting sector offset for DOS compatiblity

  Expert command (m for help): c
  Number of cylinders (1-1048576, default 1203): 239

The 239 entered in the cylinders above must be calculated based upon the size of your particular SD card.

Now Calculate the number of Cylinders for your SD card:

number of cylinders = FLOOR (the number of Bytes on the SD Card (from above) / 255 heads / 63 sectors / 512 sector size in bytes )

So for this example: 1967128576 / 255 / 63 / 512 = 239.156427 (use Google to calculate). So we use 239 (i.e. truncate, don't round).

Return to "Normal" mode:

Expert command (m for help): r

Print the partition record to check your work:

 Command (m for help): p

 Disk /dev/sdb: 1967 MB, 1967128576 bytes
 255 heads, 63 sectors/track, 239 cylinders
 Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System

Create the FAT32 partition for booting and transferring files from your PC

 Command (m for help): n
 Command action
    e   extended
    p   primary partition (1-4)
 Partition number (1-4): 1
 First cylinder (1-15, default 1): 1
 Last cylinder or +size or +sizeM or +sizeK (1-239, default 239): 50

 Command (m for help): t
 Selected partition 1
 Hex code (type L to list codes): c
 Changed system type of partition 1 to c (W95 FAT32 (LBA))

We use 50 cylinders of the total of 239 for the FAT32 partition above. The remainder of the cylinders will be used for the Linux root file system below.

Mark this FAT32 partition as bootable:

Command (m for help): a
Partition number (1-4): 1

Create the Linux partition for the root file system

 Command (m for help): n
 Command action
    e   extended
    p   primary partition (1-4)
 Partition number (1-4): 2
 First cylinder (51-239, default 51): 51
 Last cylinder or +size or +sizeM or +sizeK (51-239, default 239): 239

Print the partition record to check your work

 Command (m for help): p

 Disk /dev/sdb: 1967 MB, 1967128576 bytes
 255 heads, 63 sectors/track, 239 cylinders
 Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
 /dev/sdb1               1         50     1920955+   c  w95 FAT32 (LBA)
 /dev/sdb2              51         239               83 Linux

Save the new partition records on the SD card

This is an important step. All work up to now has been temporary.

  Command (m for help): w
  The partition table has been altered!
  Calling ioctl() to re-read partition table.
  WARNING: If you have created or modified any DOS 6.x
  partitions, please see the fdisk manual page for additional
  Syncing disks.

Format the partitions

  sudo mkfs.msdos -F 32 /dev/sdb1 -n boot
  mkfs.msdos 3.0.3 (18 May 2009)

  sudo mkfs.ext3 -L rootfs /dev/sdb2
  mke2fs 1.41.9 (22-Aug-2009)
  Filesystem label=rootfs
  OS type: Linuxsudo mkfs.ext3 -L rootfs /dev/sdb2
  mke2fs 1.41.9 (22-Aug-2009)
  Filesystem label=rootfs
  OS type: Linux
  Block size=4096 (log=2)
  Fragment size=4096 (log=2)
  95040 inodes, 379535 blocks
  18976 blocks (5.00%) reserved for the super user
  First data block=0
  Maximum filesystem blocks=390070272
  12 block groups
  32768 blocks per group, 32768 fragments per group
  7920 inodes per group
  Superblock backups stored on blocks:
	  32768, 98304, 163840, 229376, 294912

  Writing inode tables: done
  Creating journal (8192 blocks): done
  Writing superblocks and filesystem accounting information: done

Copy files onto the BOOT partition

You will need to download the demo/test files for the BeagleBoard/Trainer board combination:

  1. MLO (save as MLO)
  2. u-boot.bin (save as u-boot.bin)
  3. uImage (save as uImage)
  4. test.rootfs.tar.gz (save as test.rootfs.tar.gz)

And now copy the first three files onto the boot partition (IMPORTANT: Copy MLO FIRST! because of a bug in the X-loader which causes problems if MLO is not the first file written onto the boot partition).

 cp MLO /media/boot/MLO
 cp u-boot.bin /media/boot/u-boot.bin
 cp uImage /media/boot/uImage

Copy the files onto the Linux partition

The next step is to extract the files in test-rootfs.tar.gz into the rootfs partition (NOT the boot partition) on the SD card. This can only be done by using Linux.

 sudo tar -zxvf test-rootfs.tar.gz -C /media/rootfs

Unmount the SD card from the Linux PC and insert it into the BeagleBoard's SD connector.

Then boot your BeagleBoard while holding down the "User" button.

Trainer Schematics

The Trainer Rev-A schematic is avalible here:

The Trainer Rev-B schematic is avalible here:

Where to purchase the Trainer board

The Trainer board can be purchased from:




RevB Changes

  • Fix the silkscreen errors on the signals: GP135, GP134, GP133, and GP132. They are currently mislabeled.
  • Change the pushbutton switch (S1 - ATMEL reset switch) to a different part.
  • Move TP58 (+5V) away from the mounting hole about 0.050 inches. It can sometimes short when the mounting screw touches it.
  • Add a 2x2 header break-out for the TXD and RXD signals going to the ATMEGA328.
    • Some people want to be able to use the level translated serial signals to communicate with the Beagle/Beagle-xM instead of using it for the ATMEGA328.
    • Add two traces on the back of the board connecting the two header holes so that jumper are not required.
  • Fix the footprint on the ceramic resonator.
  • Change the I2C level translator to a PCA9306. This will allow smaller pull-ups for the I2C signals going to the AT24C01 EEPROM.
  • Eliminate resistor network RN1 and replace it with three individual 2.2K pull-up resistors (0402).

Other Links

Makezine post about the Trainer Board is located here.