Chipmakers are becoming slightly more granular in the way they position their automotive microcontrollers. Freescale and Renesas, to name two, each offer MCUs specifically for telematics. How do you select the one that’s right for your application, and what compromises, if any, do you have to make? To judge from the firms’ respective descriptions, what’s most important is the breadth and depth of application development/debug support, and the optimum combination of peripherals on-chip or readily accessible.

Freescale’s 885 MIPS MPC5200B, introduced at Telematics Detroit last year, is pin- and software-compatible with the MPC5200. It’s based on Freescale’s mobileGT architecture/infrastructure (Wind River, QNX, and Green Hills Software, etc.), and supported by the Media5200 Development System, the Lite5200B evaluation board, and various third-party firms.

Application development aids include PowerTAP run control tools; the OSEKturbo operating system; CodeWarrior Development Studio mobileGT Edition; and a Linux Board Support Package (BSP) optimized for the mobileGT architecture and Media5200 development platform.

The Media5200 includes 128MB DDR SDRAM and 64MB flash; an integrated graphics system with an 8.4-inch color LCD; a multi-channel audio subsystem with an AC’97 sound card; camera input; GPS; integrated CAN, J1850 and MOST networking support; two PCI and one mini-PCI connectors, and ATA, USB, Ethernet, S/PDIF and multiple serial connections.

Anand Ramamoorthy, general manager of Freescale’s infotainment, multimedia and telematics business, says the MPC5200B’s single (PowerPC) core is more efficient and less expensive than multi-core alternatives. The chip features a double precision floating point unit; a memory management unit-based architecture with DDR memory support; integrated PCI, ATA and USB buses; multiple serial channels; up to three I2S interfaces, and Ethernet support.

Because all applications execute on a single core, Ramamoorthy says that, for example, features like front-seat navigation can work in tandem with rear-seat entertainment. He adds that the MPC5200B can support audio compression decode/encode, as well as video decode.

Renesas is targeting cost-sensitive telematics applications with its 540 MIPS/2.1 GFLOPS SH7397 telematics chip, the “Euclid.” Based on a 300MHz SH-4A superscale core, the SH7397 is upward code-compatible with the 200MHz, SH-4-based SH7760 (“Camelot”). The new chip is at the high end of Renesas’ “compact solutions” line. The firm also offers “scalable” and “highly integrated” solutions.

The SH-4A core has two separate 32-Kbyte, 4-way set-associative cache memories, one for instructions and the other for data. Paul Sykes, product marketing manager for telematics, says the combination boosts throughput by improving the cache hit rate. On-chip, fast-access 16-Kbyte RAM also speeds processing.

The SH7397 has a built-in floating point unit, a dedicated bus for connection to external high-speed DDR SDRAM, a color LCD controller capable of approximately 64,000 colors on an 800x600-pixel LCD panel, and a USB interface with a v1.1 host and a v2.0 function controller. The controller enables connections to mobile phones, portable music players, and other consumer devices.

Other peripherals include a 4-channel 10-bit A/D converter, real-time clock (RTC), 6-channel timer (TMU), interrupt controller, and 6-channel direct memory access controller (DMAC) for high-speed data transfers to and from memory.

The SH7397 has a serial sound interface and an audio CODEC interface for transmission/reception of voice and audio data in hands-free applications. Memory card interfaces support MultiMediaCard, SD memory card, PC card, and smart card for exchange and storage of multimedia and other data. The chip includes a CAN interface, and an Ethernet controller that can be used as a general-purpose LAN interface and as a link for software debugging. It also has a 3-channel serial communication interface with FIFO (SCIF), a 3-channel serial I/O with FIFO (SIOF), and a 2-channel I2C bus interface.

Renesas’ “Sequoia” reference platform provides external memory; debug ports; peripheral functions for audio, display, and CAN; USB, PCMCIA, MMC, smart card, SD memory/IO card and Ethernet interfaces, and support for real-time operating systems (VxWorks, WindowsCE and embedded Linux) and middleware. QNX Software plans to add support for Sequoia to the QNX Neutrino RTOS.

What other devices work well for telematics applications?