BeagleBoard open source project gets shot in the ARM
BeagleBoard, the ARM-based development board from Texas Instruments, has caused a stir in the open source community, but it might not ever have appeared without the intervention of component distributor Digi-Key.
“It was developed with a little bit of seed funding from TI,” BeagleBoard software architecture manager Jason Kridner told EW. “In order to reach the right price point, we had to order 1,000 at a time with a commitment for 10,000.”
There followed a debate over who would pay, when Digi-Key stepped in.
“They put up the initial money and made the commitment,” said Kridner. “Without that, it would have been very difficult to execute the project.”
BeagleBoard is a 75x75mm mini-computer based around the powerful ARM Cortex-A8.
It is the ARM equivalent of mini single board x86 computers like Via Technologies’’ EPIA pico-ITX and Mobile-ITX motherboards, and slightly larger Intel Atom boards.
TI makes a range of OMAP ARM-based microcontrollers, some for specific applications and others for general purpose use.
“The idea was to make the OMAP chip family available to more people and to make something that would really address the needs of the open source community,” explained Kridner.
And the open source community has lapped it up. Currently, there are 164 projects registered with the BeagleBoard website.
The original BeagleBoard has three processors, all on an OMAP3530 microcontroller: A 600MHz 1,200DMIPS super-scalar ARM Cortex-A8 with 256kbyte L2 cache, a 10 million polygon/s Imagination Technologies PowerVR OpenGL ES 2.0 capable 2D/3D graphics accelerator, and a 430MHz HD video capable TMS320C64x+ DSP.
The whole thing consumes only 2W and can run from a USB cable.
There are all the usual PC-like interfaces: DVI-D video, USB, MMC+/SD/SDIO for flash cards, S-Video, stereo in and stereo out.
Following discussions with the BeagleBoard community, earlier this month TI released details of a second generation board called BeagleBoard-xM
“TI really keeps beagleboard.org separate from corporate TI,” said Kridner. “We got a tremendous amount of guidance from the community about developing the product.”
The main processor on xM is now a 1GHz Cortex-A8, and the graphics processor has the same functionality, but can render 3D at 20Mpolygon/s, twice the speed of its predecessor.
So far, TI will not disclose much about the C64x DSP on the new board, although Kridner did say that the information for the original DSP can still be used with the xM DSP.
The board is capable of displaying 720p video without invoking the mysterious C64x DSP.
“At recent classes we ran 1,280×1,024 desktop monitors at just under 60Hz,” said Kridner. “The limitation is output clock frequency, not processor power.”
One of the community projects demonstrated a 2,700×1,440 video wall using six of the original BeagleBoards.
Something that Kridner said was somewhat controversial within the community was the removal of on-board NAND flash from xM.
The original board could be configured by on-board flash or SD card, causing confusion amongst some uses.
Without on-board flash, xM can only be configured from a flash card.
“You are no longer able to misconfigure the board, it will always boot from the microSD card,” said Kridner. “You plug in a suitable card to run which ever operating system you want.”
Ethernet was the most requested addition, which TI has supplied on xM using a USB hub chip with integrated Ethernet.
This also added three more USB ports – the card sometimes needs a separate power supply if the hub is used.
A DRAM increase to 512Mbyte now allows user to build Ubuntu locally.
“Ubuntu policy is to build on the target and the compiler takes quite a few bytes,” explained Kridner. “Previously you had to cross-compile, or build on another ARM platform.”
“xM is a lot cheaper than the original if you include all of the things you used to have to buy, and a lot less messy,” claimed Kridner.
Not everything has been catered for.
For example, the serial interfaces (SPI, I2C and UART) and the general purpose IO lines are brought out to a header, but at 1.8V.
“Folks have made level-shifter daughter boards and break-out boards. There is one called Trainer with a prototype area as well,” said Kridner.
Trainer even includes an Atmel ATmega328, that is compatible with that other popular microcontroller development board, the Arduino.