Difference between revisions of "BeagleBoard Zippy2"
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Revision as of 08:47, 4 June 2012
The Zippy2 Ethernet Combo Board (KSZ8851SNL-BBE-EVAL) is a low cost expansion board for the BeagleBoard that provides the following peripherals:
- 10/100BaseT Ethernet
- Second SD/MMC Interface
- Second RS232 Serial Interface
- Real-Time clock with Battery Back-up
- I2C Interface (+5V level)
- AT24C01 Serial EEPROM for Board Identification
- 1 Hardware
- 2 Soldering BeagleBoard's Expansion Header
- 3 Creating a bootable SD card in Ubuntu
- 4 Automated script to create a bootable SD card
- 5 Design Documents
- 6 Software Links
- 7 Programming the Zippy2
- 8 Where to purchase the Zippy2 (KSZ8851SNL-BBE-EVAL)
The Zippy2 provides a standard 10/100BaseT (10/100 Mbit) Ethernet interface and uses Micrel's KSZ8851SNL SPI to Ethernet controller.
The Zippy2 provides a second SD/MMC interface that supports both 3.3V and 1.8V SD memory cards.
RS232 Serial Interface
The Zippy2 provides a second RS-232 serial port for the BeagleBoard: There are two serial connectors provided.
- Standard DB9 Male connector
- 2x5 shrouded header (0.1 inch pin spacing).
The Zippy2 provides a battery backed-up Real Time Clock (RTC) which uses the Maxim DS1307. The backup power is provided by a small 3V lithium coin battery and is held in place by a battery holder.
Compatible 3V Lithium Coin Batteries:
Battery cell size = 12mm.
The battery is not included with the Zippy2 and must be purchased separately. Compatible batteries are available from Digi-Key:
Installing the 3V lithium coin battery:
Insert the battery with the positive "+" side up.
Slide the battery all the way into the battery holder.
The Zippy2 provides a 4-pin header expansion connector for access to the BeagleBoard's I²C signals. The signals have been level translated to 5V to allow easy connection to standard 5V peripherals.
I²C expansion header pin assignments:
- pin 1 - +5V Power
- pin 2 - SDA (5V signal level)
- pin 3 - SCL (5V signal level)
- pin 4 - Ground
The Zippy2 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 Zippy2. More information can be found on the Beagle Board Pin Mux Page.
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).
Insert the 2x14 Header’s SHORT PINS from the back side of the BeagleBoard into the BeagleBoard’s expansion connector (J3).
Position the 2x14 Header so the LONG PINS are on the BACK SIDE of the BeagleBoard.
Solder the SHORT PINS of the 2x14 Header from the TOP SIDE of the BeagleBoard.
Attaching to the BeagleBoard
Attach the four board spacers with the screws provided.
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.
Continue pushing the two boards together until the connectors mate together.
Attach the male standoffs as shown.
Creating a bootable SD card in Ubuntu
This guide will demonstate how to create a dual-partition SD card for the BeagleBoard/Zippy2 combination to boot Linux from the first partition and have the root file system located on the second partition.
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
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) p 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) ''p'' 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 information. 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/Zippy2 combination:
- MLO (save as MLO)
- u-boot.bin (save as u-boot.bin)
- uImage (save as uImage)
- 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.
Automated script to create a bootable SD card
The following script will create a formatted SD card using your Linux PC.
Make a working directory for the files: mksdcard.sh, MLO, u-boot.bin, uImage, and test-rootfs.tar.gz and copy them into it.
You will also need to make two mount points:
mkdir /mnt/sdcard1 mkdir /mnt/sdcard2
Then from inside the working directory you created above, issue the command like this:
Where /dev/sdb is the drive for the SD card.
This should generate a fresh bootable SD card for you!
The following are the design documents for the Zippy2 (KSZ8851SNL-BBE-EVAL) board:
The latest Linux driver for the KSZ8851SNL is included in the mainline Linux kernel and can be downloaded here:
Also, Linus' GIT repo can be pulled from here:
Or you can view just the driver:
Programming the Zippy2
All of the devices on the Zippy2 work as standard linux devices which means any reference material for these devices is applicable:
How to access the I2C bus (from software): http://i2c.wiki.kernel.org/index.php/Linux_2.6_I2C_development_FAQ
How to access the second UART: http://tldp.org/HOWTO/Serial-HOWTO.html and http://www.vanemery.com/Linux/Serial/serial-console.html
How to use and configure the Ethernet port: http://tldp.org/HOWTO/Ethernet-HOWTO.html
How to access the SD card: If you are using the Angstrom images, then all you have to do is insert the SD card and it will be automatically mounted. To check just issue the command "mount" at the prompt to view the currently mounted devices.
To set the real time clock (RTC) on the Zippy2 board:
First: Set the date:
date -s 2010.02.15-17:52
(date -s YYYY.MM.DD-HH:SS (the time HH:SS is in 24 hour format)
Then write the current date into the RTC's hardware registers:
As long as you have a good backup battery (the small coin battery), the RTC should keep the time correct even if you remove power and boot-up the BeagleBoard at a later time.
Where to purchase the Zippy2 (KSZ8851SNL-BBE-EVAL)
The Zippy2 can be purchased from TinCanTools.com here.