2013 Joint International Conference on Rural Information & Communication Technology and Electric-Vehicle Technology (rICT & ICeV-T)

November 26-28, 2013, Bandung-Bali, Indonesia

978-1-4799-3365-5/13/$31.00 ©2013 IEEE

Design and Implementation Audio Processing in Angstrom Beagleboard

Rifki Wijaya#1, M. Vicky Ghani Aziz#2, Ary Setijadi Prihatmanto#3, Wisnu Siswantoko#4 #Sekolah Teknik Elektro dan Informatika, Institut Teknologi Bandung

Jl Ganesha 10 1rifkiwijaya@gmail.com

2vickyaziz@live.com 3asetijadi@lskk.ee.itb.ac.id 4wisnu.siswantoko@gmail.com

Abstract— This paper describe an implementation of audio processing in beagleboard. Audio processing in beagleboard can be done with some prerequisite software. Angstrom is operating system based on linux and portaudio is library for accessing audio port, both of them are important software. One beagleboard and two sound card can transfer full-duplex communication from one device to another. Analog audio transformed into digital data and then pre-processed in transmitter device and transform again into analog signal to be transmitted and vice versa. Keywords— audio processing, beagleboard, digital audio, analog audio.

I. INTRODUCTION There are few way to transfer audio from one phone to

another. Vega use xookynabox to transfer audio from analog to digital and back again to analog[1].

We need to explore the possibilities of open hardware in conjunction with open source software. These possibilities is to close the gap between music producers, musicians and the hardware used to create their sounds. It can be predicted that the closer the sound workers get to the tools they use, the more expressiveness and creativity that can be achieved.

A. Beagleboard The BeagleBoard is a low-power open-source hardware

single-board computer produced by Texas Instruments in association with Digi-Key and Newark element14. The BeagleBoard measures approximately 75 by 75 mm and has all the functionality of a basic computer.

The Beagle is based on a PoP (package-on-package) sandwich combining TI's OMAP35xx processor with 128MB of 166MHz DDR RAM and 256MB of NAND Flash. Storage is expandable via a real SD/MMC+ slot onboard.

NAND flash memory is a type of non-volatile storage technology that does not require power to retain data. An important goal of NAND flash development has been to reduce the cost per bit and increase maximum chip capacity so that flash memory can compete with magnetic storage devices like hard disks[2].

Fig . 1 Package-on-package, with processor, flash, and RAM

The board eschews any device-specific LCD interface, in favor of DVI and DVI-D chips aimed at gluelessly supporting most any inexpensive display, the project says. The board boasts dual independent displays, including an HDMI connector that, with an HDMI-to-DVI cable, supports external flat-panel displays up to XGA (1024x768) at 65 MHz and 24-bit ("true-color") pixel depth. There's also an S-video port.

Onboard I/O interfaces include:

• USB OTG (high-speed) • USB 2.0 host port • 9-pin RS-232 header • Audio I/O with 1/8-inch stereo mini-jacks • S-video port • 14-pin JTAG • Power LED, three software-controlled LEDs • Reset and user-programmable buttons

This paper use beagleboard C5. Beagleboard using 720MHz OMAP3530DCBB72 processor version in 0,4 mm PoP(Package on Package) packet.

Fig . 2 Beagleboard C5

Here it is list of beagleboard features.

TABLE I BEAGLEBOARD FEATURES

Feature Processor OMAP3530DCBB72 720MHz

POP Memory Micron 2Gb NAND (256MB) 2Gb MDDR

SDRAM (256MB)

PMIC TPS65950

Power Regulators Audio CODEC Reset USB OTG PHY

Debug Support 14-pin JTAG GPIO Pins UART LEDs

PCB 3.1” x 3.0” (78.74 x 76.2mm)

6 layers

Indicators Power 2-User Controllable PMU

HS USB 2.0 OTG Port

Mini AB USB connector TPS65950 I/F MiniAB

HS USB Host Port Single USB HS Port Up to 500ma Power

Audio Connectors 3.5mm 3.5mm L+R out L+R Stereo In

SD/MMC Connector

6 in 1 SD/MMC/SDIO 4/8 bit support, Dual voltage

User Interface 1-User defined button Reset Button Video DVI-D S-Video Power Connector USB Power DC Power

Expansion Connector (Not Populated)

Power (5V & 1.8V) UART McBSP McSPI I2C GPIO MMC PWM

2 LCD Connectors Access to all of the LCD control signals plus I2C

3.3V, 5V, 1.8V

B. Sound card

Fig . 3 Virtual 7.1 Channel USB 2.0 Sound Card Adapter Dongle

Here it is feature product and specification. • USB 2.0 Full-Speed (12Mbps), USB audio device

compliant • USB Bus powered, no external power needed

• Connectors : USB Type-A, Stereo output jack, Microphone-input jack

• Functional keys : Microphone - Mute, Speaker - Mute, Volumn up and - Volumn Down

• LED Indicator : green for Power and red for Microphone-mute

• USB interface allows you to easily add sound to any notebook or desktop computer

• Include Xear 3D, the virtual 7.1 channel sound simulation software

• 7.1 Channel Sound Adapter supports Windows 98SE/ME/2000/XP/Vista, Linux, Mas OS

• Transform analog Sound Signals to Digital

C. USB hub USB OTG port can be used as the primary power source

and communication link for the BeagleBoard and derives its power from the PC via USB cable. Port the client is limited in most cases to 500mA by the PC. A USB port is enough to power a single PC BeagleBoard. If additional devices are connected to the expansion bus and 5V rails are used to power them or if a high-powered USB devices are connected to the EHCI port, the power required to exceed that provided by the USB port or hub.

It is possible to bring this to 1A by using a Y cable if the additional power required for host USB port or an expansion card. The following figure shows and example of Y-Cable for USB.

Fig . 4 USB Y cable

Fig . 5 D-Link DUB-H4 4 Port High Speed USB 2.0 Hub

II. DESIGN AND SCENARIO

A. Beagleboard Usage Scenario Beagleboard has output port to LCD, there is S-video and

HDMI. Some operating system do not use LCD to control beagleboard. Mouse and keyboard is also not used for some operating system such as angstrom and another server operating system such as Ubuntu server. When Ubuntu, WINCE, Debian, and Archlinux as operating system they need monitor, keyboard and mouse to operate them.

Here it is scenario usage of beagleboard.

Fig . 6 beagleboard usage scenario

USB hub is used to get more power to carry out two sound card and USB flash disk. SDCARD is need to install OS angstrom on NAND or install on SDCARD itself.

B. Step by step test scenario Hardware Requirement test is mention below

• Beagleboard • Two sound card • USB hub with power from adapter • SDCARD • Adapter power for beagleboard • Debugging cable serial to USB • Macintosh • Two headphone • Two handphone with Bluetooth feature • Flashdisk

Software requirement test is mention below

• Image angstrom for beagleboard • Win32disk imager(to load image angstrom to SDCARD) • Gzip • Beagle_Revc5_Validation • minicom

This scenario need internet with direct connection, no

proxy no username, if there is connection like that it will simplify the step.

Scenario test is mention below.

Fig . 7 Test Scenario

III. TEST RESULT Macintosh is used to share internet from wifi to

beagleboard using USB to serial. Sharing is possible since macintosh has feature to share internet from LAN, wifi or VPN to other connection.

Fig . 8 Setup scenario beagleboard

Angstrom image is added into SDCARD using win32disk imager. Angstrom image on SDCARD write into NAND using user button on beagleboard. Beagleboard now can run angstrom without using SDCARD. SDCARD can be released to boot into NAND.

Fig .9 Two sound card with USB hub connection on beagleboard

Booting into angstrom took not less than a minute. It is

when no other application installed. In Angstrom we can add startup application to adjust our need. Application added in startup by placing the binary in path /etc/init.d/.

Fig . 10 Angstrom beagleboard booting.

Beagleboard now can start voice chat from one sound card to another. We can change the sample rate of the sound by changing at the code.

Fig . 11 Application to start voice chat from one sound card to another.

IV. CONCLUSIONS It is possible to do audio processing on beagleboard

especially on top of the OS angstrom. Audio processing can be encrypt and modulated using digital data.

Possibilities of open hardware in conjunction with open source software in this case Angstrom is available. This development can close the gap between music producer, musicians and the hardware used to create their sound.

REFERENCES [1] Vega, Rafael, and Daniel Gómez. "Using the BeagleBoard as hardware

to process sound." [2] (2013) The what is website. [Online]. Available:

http://whatis.techtarget.com/definition/NAND-flash-memory [3] David Vescovi. (2011) Procedure for preparing SD card for card based

image booting. [Online]. Available: https://beagleboardbsp.codeplex.com/documentation

[4] "USB-powered Beagle Board from Digi-Key Unleashes Community Development". Digi-Key. July 28, 2008. Retrieved May 12, 2011.

[5] M. Wegmuller, J. P. von der Weid, P. Oberson, and N. Gisin, “High resolution fiber distributed measurements with coherent OFDR,” in Proc. ECOC’00, 2000, paper 11.3.4, p. 109.

[6] "Android On Beagle". Beagleboard.org. Retrieved 2010-02-04. [7] Coley, Gerald (2009-08-20). "Take advantage of open-source

hardware". EDN. Retrieved October 13, 2011.