Design and Implementation of mobile multimedia communication terminal based on omap1510 dual-core architecture

Design and Implementation of mobile multimedia communication terminal based on OMAP1510 dual-core architecture

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Source: Electronic Technology Application Author: mei Xiaolan Zhang Qifang Mei qibin

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The third-generation (3G) wireless communication technology will provide real broadband services for cellular communication systems and personal communication systems. Service providers will provide higher-level wireless multimedia services, including data, audio, video, and voice services. To fully tap the potential of 3G Multimedia Communication, system developers need a new type of software and hardware technology. Therefore, the hardware platform must have high performance, low power consumption, and high integration. Because it must comply with multimedia, mobile operating systems, end users and other standards, but also must comply with a large range of changes, so programming must have greater flexibility.
The development of mobile communication requires more and more digital signal processors, and traditional DSP chips are no longer competent. To meet the needs of new Applications in the mobile communication and Multimedia fields, Texas Instruments Corporation proposed the architecture of Open Multimedia application Platform OMAP (Open Multimedia Applications Platform) and designed an OMAP chip for this purpose. It uses a unique dual-core structure that combines a high-performance, low-power DSP core with an ARM microprocessor with strong control performance to form a highly integrated SoC. It is an open and programmable DSP-based architecture. Because of the advanced and unique structure of OMAP, its chip processing capability is strong and its power consumption is low. It has obvious advantages in mobile communication and multimedia signal processing.
The mobile communication market is growing and wireless Internet applications are growing. Separated terminals are gradually merged into a single multimedia terminal device. New applications, such as MPEG4, TTS, Internet audio, and video conferencing, require processors with higher functionality and lower power consumption. The OMAP chip fully meets the requirements of these new applications. In addition, the Open Architecture of OMAP makes it easy for third-party developers to develop new wireless multimedia applications. The technical advantages of OMAP in mobile communication and multimedia signal processing make OMAP chip very suitable for third-generation mobile phones, wireless digital assistants, and future handheld computers.
TI currently provides a variety of OMAP platforms, including OMAP1510 dual-core architecture processors. OMAP1510 provides an excellent platform for the development of 3G multimedia wireless devices.
1 omap1510 hardware architecture
The OMAP hardware architecture consists of DSP core, ARM core, and Traffic Controller. The three parts can manage the clock independently to effectively control the power consumption, as shown in 1. The TI-enhanced ARM925 core is an advanced representative of the arm risc architecture. Its operating frequency is 175 MHz. It includes memory management units, 16 K bytes of High-speed instruction buffer memory, 8 K bytes of data high-speed buffer memory and 17-word write buffer. The disk contains MB of internal SRAM, which provides a large amount of data and code storage space for applications such as LCD display. It has 13 Internal interruptions and 19 external interruptions, and uses two-level interrupt management. In addition, there are ARM CP15 coprocessor and protection modules in the kernel. The C55x DSP core has the optimal power consumption performance ratio and the working frequency is 200 MHz. It adopts three key innovative technologies: an increasing idle power-saving area, a variable-length instruction, and an extended parallel mechanism. Its structure is highly optimized for multimedia applications and is suitable for low-power real-time voice image processing. The C55x DSP core provides hardware accelerators for processing motion estimation, discrete cosine transformation, discrete cosine inverse transformation, and 1/2 pixel interpolation, reducing the power consumption of video processing. The C55x DSP core contains 32 K double-access SRAM, 48 K single-access SRAM, and 12 K high-speed command cache. In addition, the core also contains memory management units, two-level interrupt manager, and direct memory access units. The OMAP1510 chip has a variety of peripheral interfaces, such: LCD controller, memory, camera, air, Bluetooth, universal asynchronous transceiver, I2C host, pulse width audio generator, serial, master client USB, secure digital multi-media card controller, keyboard and Other interfaces. These rich peripheral interfaces make OMAP1510 particularly suitable for third-generation mobile communication systems.

 

2 omap1510 Software Architecture
The OMAP software architecture is built on two operating systems: one is an ARM-based operating system, such as Windows CE and Linux, and the other is a DSP/BIOS based on DSP. The core technology used to connect two operating systems is DSP/BIOS bridge. It is the key to implementing and using OMAP. For software developers, DSP/BIOS bridge provides a seamless interface using DSP, allowing developers to use standard application programming interfaces on GPP (general-purpose processors, including arm, access and control the running environment of DSP. Using Ti's Code Composer Studio integrated development environment, from the developer's perspective, OMAP seems to have completed all the processing functions with only the GPP processor. In this way, developers do not need to program separately for the two processors, which greatly simplifies programming. In the OMAP architecture, developers can program the OMAP dual-processor platform just like a single GPP.
Omap1510 supports multiple real-time multi-task operating systems working on arm925 microprocessor. It is used to manage real-time multi-task scheduling of arm925 microprocessor and control and communicate with DSP c55x, it also supports multiple real-time multi-task operating systems on DSP c55x to implement complex multimedia signal processing. DSP/BIOS bridge includes DSP manager, DSP Management Server, Ram, DSP, and peripheral interface link driver. DSP/BIOS bridge provides communication management services between applications running on arm925 and algorithms running on DSP c55x. Developers can use the Application Programming Interface in the bridge to control the execution of real-time tasks in the DSP, and exchange the running results and status messages with the DSP. In this environment, developers can call the local DSP Gateway component to complete functions such as video, audio, and voice. Therefore, developers can develop new applications without having to understand DSPs and the bridge, as shown in figure 2.

 

When developing multimedia applications, you can use the multimedia engine through the standard Multimedia Application Programming Interface (mm api) to facilitate application development; the multimedia engine uses DSP/BIOS bridge for DSP tasks through DSP Application Programming Interface (dsp api; finally, the DSP/BIOS Bridge coordinates the data, I/O stream, and DSP task control. 3.

 

3 dual-core communication
The OMAP software platform is independent of the hardware platform. How to make the two operating systems work seamlessly is the key to implementing an open software platform. Its core technology is to formally apply the DSP/BIOS Bridge On The OMAP platform. The DSP/BIOS bridge is used to connect the DSP and the OS on other general-purpose processors (GPP. GPP can be ARM in OMAP or MIPS (Microprocessor without Interlocked Pipe Stage. The DSP/BIOS bridge is used in an asymmetric, multi-processor environment consisting of a general-purpose processor (GPP) and one or more DSPs. As a software combination of gpp OS and dsp OS, DSP/BIOS bridge connects two operating systems. This connection enables GPP clients to exchange information and data with tasks on DSPs. There are two types of connections: Message subconnection and data stream subconnection. Each seed connection transmits messages in sequence. A message is first sent to the message chain, and a message is first transmitted. A same data stream is first sent to the data stream chain, and a data stream is first transmitted. Each sub-connection performs operations independently. For example, GPP sends a data stream and then a message. If a message has a high priority, the message is sent to the DSP first than the data stream.
DSP tasks generally use message objects to transmit control and status information, and data stream objects to transmit efficient real-time data streams. Figure 4 shows the relationship between GPP client programs and DSP tasks.

 

4 typical applications
4.1 multimedia terminal hardware solution
The hardware architecture solution 5 of the 3G mobile multimedia terminal based on OMAP1510 is shown in. The 3G mobile phone card provides air interface functions based on the 3G wireless transmission technology (RTT) specification, including the RF module, baseband processing module, and corresponding physical layer software. This solution adopts the technical specifications of CDMA. The interface between 3G mobile phone card and OMAP1510 can be implemented through the TI peripheral bus interface.

 

4.2 protocol software design scheme based on CDMA
The implementation of CDMA is divided into two stages: CDMA 2000-1X and CDMA2000-3X. The data rate of the former is 144 kbps, while that of the latter is 144 kbps, the number of mobile walking users is 384 kbps, and the number of indoor fixed users is 2 Mbps, supports high-speed Multimedia grouping data and voice services such as wireless Internet access and conference and television. The following describes the protocol software structure of mobile multimedia terminals.
The terminal protocol structure consists of the signaling protocol stack and Application Service protocol stack. The protocol software structure of the 3G mobile multimedia terminal based on CDMA 2000 is shown in Figure 6.

 

The signaling protocol stack of CDMA includes the high-level Signaling Layer, the data link layer (divided into the LAC sub-layer and the MAC Sub-layer), and the physical layer. The high-level Signaling Layer mainly describes the signaling structure, security authentication, signaling control and application, and Message format. The LAC sublayer provides the reliability guarantee for signaling transmission, including authentication, ARQ, functions, segmentation and re-installation, etc. The MAC Sub-layer implements Logical Channel service re-division and QoS control, and the physical layer implements data encoding/decoding, modulation/demodulation, and other physical channels.
The application service protocol stack includes multimedia video/audio codecs, real-time transmission protocol (RTP), call control signaling protocol, TCP/IP, and PPP. Multimedia Applications in the 3G mobile communication system are based on IP group data exchange. Call Control Management of multimedia sessions is completed by a set of signaling protocols. There are two common types: H.323 (group-based Multimedia Communication System) and SIP (Session Initiation Protocol ). The H.323 protocol set shown in Figure 6 is a widely used signaling protocol set. The video decoder adopts the H.263 standard and the audio decoder adopts the G.723 standard. RTP and Its paired protocol RTCP provide information related to the peer-to-peer multimedia application layer, while UDP can reduce the transmission delay of real-time multimedia streams. H.225.0 and H.245 are respectively H.323 call control protocols, running on TCP.
Another important component of mobile multimedia terminal software is the embedded operating system. Currently, popular embedded mainstream operating systems include VxWorks, WinCE, and Linux. Among them, Linux is open source code, with low costs and high development potential. It supports multiple processors such as arm, PowerPC, and x86. Therefore, this solution uses an embedded Linux operating system. The embedded Linux operating system can be independently developed or purchased for commercial use, such as μC Linux.
Mobile Multimedia is the main feature of the third generation mobile communication system. Therefore, it is critical to select a platform for 3G mobile terminals with multimedia functions. Omap1510 is designed with an open software architecture and dual-CPU hardware channel. It is easy for developers to program and integrate. With the formation and maturity of the 3G business market in the future, the demand for 3G mobile multimedia terminals will become larger and larger. In this paper, the implementation scheme of 3G mobile multimedia terminal based on omap1510 is discussed in connection with CDMA, one of the technical specifications of 3G wireless transmission. This terminal implementation scheme has been verified by relevant scientific research projects and is highly feasible.