EE Times Under the Hood - June 23, 2008 - (Page U48)

UTH0623COMP_pg42_55.qxd 6/11/08 4:32 PM Page 48 under the hood: w w w. e e t i m e s . c o m C OMPUT ERS & GAM I NG • w w w. t e c h o n l i n e . c o m Their use brings integrity issues into play, for which the layout must be optimized. For example, care must be taken in how the Mobile DDR memory bus is connected to the microprocessor. Freescale writes some very specific application notes to help designers navigate through these trouble spots. On the software side, Sony had to write the application on top of the operating systems. That can get tricky, since the proper drivers must be loaded as needed. This is where the power management comes into play as well. It’s necessary to make sure that only the peripherals that are needed are turned on at any given time. Using the E Ink architecture rather than a standard LCD entailed some special circuitry. The system that I took apart used a Ricoh R5C807 to enable the E Ink technology. However, I’ve learned that the reference design that’s used by E Ink, as well as the latest e-book platforms from Sony, make use of an Actel ProASIC3 FPGA. Both devices also serve as an interface to the external memory cards. The FPGA, which functions as a display driver interface, takes the input from the host processor and acts as a bridge interface to it. The FPGA is also used for various lookup tables and display and power drivers. These functions are needed to implement E Ink’s “blanking” process, which stores the drivers needed to display the next “page” in the book. In other words, one page must go blank (or black) before the next one can be loaded. Martin Mason, a senior director at Actel, acknowledged that this was one of the more difficult challenges in the design. “It’s not so much a function of the drive electronics. It’s more a function of the display technology itself,” said Mason. Actel maintains that the security and low-power features of the ProASIC3 are what drew Sony to the part. ■ Richard Nass is editor in chief of Embedded Systems Design magazine. He can be reached at rnass@techinsights.com. tion on the display, but clearly, this is not the case. The processor that’s inside the reader is not exactly state of the art. It’s a Freescale Semiconductor DragonBall i.MXL applications processor, also known as the MX1 (more specifically, MC9328MXL). Designed circa 2002, this was Freescale’s first ARM-based processor. It has a 200-MHz ARM920T core surrounded by all the usual peripherals, like a UART and memory and SPI interfaces. It’s also got an integrated Memory Stick interface, which Sony took advantage of. While the PRS-500 is fairly new to the U.S. market, it’s been available in Japan for a number of years. That likely explains the use of the older microprocessor. Even though newer versions of the i.MX family are available, Sony would have to make changes to the software if it swapped processors. Some of the software could likely be reused, but that would depend on which processor was picked for the CPU upgrade. While a DSP would seem a likely choice, it would require a major change to the operating system stack. For designs such as the Sony e-book, Freescale is now promoting its i.MX31 microprocessor, based on the ARM11 core. It runs at 533 MHz. It’s not the company’s latest offering, but it’s well suited for an e-book design. “If they did want to switch processors, we’d probably be heavily involved,” said Boris Bobrov, manager of the Customer Projects Office at IN BRIEF Sony’s Portable Reader System (PRS) 500 circumvents many of the problems that plagued earlier electronic readers.The biggest problem was the readability of the display, which was overcome with the help of a key supplier, E Ink. Using E Ink’s Vizplex technology, the high-contrast (fourlevel grayscale), high-resolution (170 pixels/inch) display can be read in bright sunlight and offers a near-180° viewing angle.The PRS-500 sells for less than $300, it’s about a half-inch thick, about 7 x 5 inches in length and width, and weighs just 9 ounces.The readable display area measures 6 inches diagonally, which is about the same as one page in a paperback book.Aside from having buttons that were a little hard to navigate, this is a nice product. Freescale’s Multimedia Applications Division. “We have a customer support team in Japan that could have engaged with Sony if they needed our help. Depending on the customer’s wants and needs, we can be on site for them or not. In addition to assisting with the software, we can review schematics for the hardware or layout.” One of the difficult parts of this design, at least on the hardware side, comes from its high-speed buses. Component focus Sony’s e-book is designed with 64 Mbytes of internal memory, which the company claims is enough to store about 80 books.The processor that’s inside the reader is not exactly state of the art. It’s a Freescale DragonBall i.MXL applications processor, also known as the MX1 (or, more specifically, the MC9328MXL), designed around 2002. It was Freescale’s first ARM-based processor, incorporating a 200-MHz ARM920T core.The core is surrounded by all the usual peripherals, like a UART and memory and SPI interfaces.The Vizplex imaging film is designed for high performance with black-and-white electronic-ink pigment formulations. It’s brighter and offers a faster response time than previous-generation active-matrix imaging film. In addition, it can be manufactured in larger sizes, up to 9.7 inches. 48 Electronic Engineering Times, TechOnline | June 23, 2008 http://www.techonline.com http://www.eetimes.com

Table of Contents Feed for the Digital Edition of Under the Hood - June 23, 2008

Under the Hood - June 23, 2008 Extreme Design: SuitSat Pushes Desigers' Limits Evolution of the Smart Phone Mature Devices get Rolly Rocking GPS: Garmin Nuvi 750 vs. HP iPaq 310 Inside the Sony OLED TV Multizone Dgital Audio Flip Ultra Camcorder - An Ode to Clean Design Robot Guitar Tunes Itself E-book is a Sight for Sore Eyes Scientific Calculator Boils Down to Two ICs $100 BOM Eludes First OLPC Laptop 45 nm: What Intel Didn't Tell You Next Step in NAND Flash Evolution Surveillance on a Shoestring Hot 3G Phone Owes Debt to Analog SecurID Fob: Single-Chip Safety Net

Under the Hood - June 23, 2008

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