Linux-friendly SoCs target low-end multimedia
Jul 8, 2008 — by Eric Brown — from the LinuxDevices Archive — 5 viewsRenesas announced two highly integrated system-on-chip (SoC) processors based on its 32-bit RISC architecture. Aimed at low-end multimedia applications, the SH7262 and SH7264 processors each boast SuperH cores clocked at 144MHz, a 1MB SRAM buffer, 18 to 20 peripheral functions, plus support for VGA-size TFT LCD panels, says Renesas.
The SH7262 and SH7264 models are the latest in the Renesas line of SuperH processors. These include the recently released SH7723, a 400MHz version aimed at car navigation systems, as well as the earlier 266MHz SH7722 , which targets mobile applications.
The two new parts each come in a variety of models designed for digital audio systems, MP3 media player accessories, automotive dashboard displays systems, and industrial man-machine interfaces (MMI). According to Renesas, the high degree of integration, including memory and peripherals, offers a single-chip design for low- and mid-range applications. The only additional IC required is a read-only ROM chip for software storage, says the company, although additional external RAM would also be needed to run Linux.
SH7262 / SH7264 diagram
(Click to enlarge)
The processors use the company's SH2A-FPU SuperH core (with 16KB cache), as opposed to the more powerful SH-4A core used by the SH772X series. The company claims processing performance of 346 MIPS (Dhrystone 1.1 benchmark) and 288 MFLOPS. Renesas also touts the SoCs's signal-processing performance and high ROM code efficiency, which together are said to improve compression and decompression of audio data in formats such as MP3, WMA, or AAC (Advanced Audio Coding), leading to reduced program size. The SH7262 is packaged in a 176-pin QFP, offering four channels of A/D conversion, whereas the SH7264 comes in a 208-pin QFP, with eight A/D channels.
A 16-bit external data bus supporting 48MHz rates provides for direct connection to external memory such as flash ROM, SDRAM, or SRAM, thereby supporting complex operating systems such as Linux. The 1MB of integrated SRAM can be configured as a frame buffer for temporary storage of video data, enabling the SoCs to control a WQVGA-size TFT LCD panel (480 × 240 pixels) without external SDRAM. Larger displays up to VGA quality are supported if external SDRAM is used for the frame buffer, says Renesas.
Each of the processors are sold in eight models, differentiated by support for CAN or IEBus interfaces, as well as temperature range. Some of the parts support -4 to 185 degree F (-20 to 85 degrees C) temperatures whereas others go from -40 to 185 degrees F (-40 to 85 degrees C). On-chip functions include a new video display controller and digital video input pins that support applications including rear-view or side-view cameras, video recording, image-size reduction, alpha-blending effects, and superimposition of video inputs. Other functions include:
- Motor-control pulse width modulation (PWM) timer for controlling up to four gauge displays
- SD memory-card interface
- Hardware circuit for decompressing graphical data
- USB 2.0 Hi-Speed host/function interface
- Audio signal processor
- CD-ROM decoder
The SoCs offer an on-chip debugging function supporting the full 144MHz frequency, says Renesas, and there is an optional E10A-USB emulator, which runs off USB bus power. Digital audio compression middleware is also supplied, along with software supporting ISO 9660 and FAT32. Renesas says it is working on a future development platform that includes a reference board and additional middleware, including GUI libraries, development tools, and real-time operating system (RTOS) support.
Availability
The SH7262 and SH7264 series will be available in the third quarter, with over-10K prices starting at $12, says Renesas. More information should be available here
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