Pegasus: An Ideal Digital Signage Display Solution

Customer

A Russian developer of digital signage displays, information displays and other digital signage devices.

Objective

The customer developed Pegasus, an innovative platform for digital signage displays and information displays. Full Linux support had to be provided for the whole set of chips and interfaces installed on the Pegasus platform, as well as external modules and daughter-boards. Also, an embedded Linux distribution had to be developed, with a set of applications that demonstrate the hardware platform capabilities.

Hardware

The Pegasus platform is based on the Samsung S3C6410 processor, with 128 Mb RAM and 128 Mb NAND flash. The platform includes a WiFi/Bluetooth combo module, an audio codec and GSM/GPRS connectivity. It has a possibility of connecting a display with a LVDS or RGB interface with a sensor panel. The platform is fitted with connectors for SD/MMC, microSD and SIM cards, USB devices as well as two VGA cameras. It also has two accelerometers and an NFC (RFID) module.

The Pegasus platform is based on the Samsung S3C6410 mobile processor which provides support for the whole set of periphery, and video content playback. S3C6410 was specifically designed for low-power mobile devices with extended multimedia capabilities. It is built around the 32-bit ARM1176 core and fitted with an embedded multi-format codec.

RAM: 2õ512 Mb 16-bit mobile DDR connected to the processor through a 32-bit interface using an embedded DRAM controller.

Program Storage: 1 Gb NAND Flash, connected to the processor through a 8-bit multiplex interface using an embedded NAND controller.

The WM8753 audio codec is connected to the processor through an I2S interface and provides stereo audio content playback and microphone connection. A connection with a GSM module through a PCM interface makes it possible to set up voice communication.

Video information from the processor display controller is converted from the RGB interface to LVDS through the SN75LVDS83 converter and transmitted to the LCD display with an embedded LVDS controller.

The sensor panel can be connected to the Touch screen controller through four analog inputs.

Murata SP-W8ME2, a WiFi/Bluetooth combo module, is connected to the processor through the SDIO and UART interfaces and provides the following connection interfaces: 802.11 b/g and Bluetooth 2.1 + EDR.

GSM/GPRS connectivity is available as pluggable modules (Wavecom Q2687, AnyDATA DTM-500A, AnyDATA DTP-601W) which can be connected to the processor through the UART and USB interface. They can provide voice communication through a microphone when connected to the audio codec.

The board is fitted with: a CS8900A Ethernet controller, two BMA150 accelerometers with an SPI interface, 2 USB ports, SD and microSD connectors and Microread NFC.

The LTC3555 power management IC relies on a USB power source and provides battery power delivery simultaneously charging the battery.

Software Platform

The customer needed a quickly configurable software platform with a possibility of installing additional software on existing digital signage displays on advertising sites. The system of the choice was OpenEmbedded, a software framework to create Linux distributions for embedded Linux-based solutions. OpenEmbedded has a number of advantages:

• Support for a widerange ofprocessor architectures;
• Targets embedded applications;
• Support for a package management system (opkg);
• Centralized assembly and configuration management;
• Support for a large number of software packages (over 1,500);
• A large community of developers;
• Support for a set of various Linux distributions;
• Easy to expand and customize;
• Tools for creating software development kits (SDK);
• Runs on any Linux distribution.

Angstrom 2008.1 based on an OpenEmbedded framework was selected as the Embedded Linux basic distribution for the project. Some of its advantages include:

• Support for a package management system (opkg);
• A set of ready-to-use startup scripts;
• Optimized completion of the installed software;
• Installed software stability.

The Linux kernel selected for the project was 2.6.31-rc4 version with many architecture specific modifications for the S3C6410 processor and multimedia interfaces.

Solution

The project involved providing full Linux support for the whole set of chips and interfaces installed on the Pegasus platform, as well as external modules and daughter-boards.

Specifically, the project included the following tasks:

• Creation of an OpenEmbedded based build framework;
• Improvement of the USB Host and USB OTG driver;
• Improvement of the SPI bus driver;
• Improvement of the BMA150 accelerometer driver;
• Development of a robust versatile system for updating digital signage solutions firmware;
• Improvement of the video drivers for high-definition mode support;
• Improvement of the media player MPlayer with support for MPEG4/H.264 video decoding through an embedded multi-format codec;
• Development of power management drivers for the LTC3555 and DS2745 integrated circuits;
• Creation of a versatile Angstrom-2008.1 based distribution with automatic setting of the following subsystems: WiFi, WiMax, CDMA, GPRS, SD, Ethernet, Bluetooth;
• Change from core version 2.6.21 to 2.6.31;
• Creation of a software development kit for third-party digital signage application developers;
• implementation of a set of applications that demonstrate the hardware platform capabilities;
• Implementation of external CDMA/EVDO modem support;
• Implementation of external GSM/GPRS/EDGE modem support;
• Implementation of external WiMax module support;
• Implementation of support for two video cameras on the external module.

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