Sharp's ARM-based System-on-Chip

Price and battery life are definitely two of the top criteria for mobile devices. They're all currently too expensive and the stamina of a single charge could definitely be improved. There's nothing like whipping out your $500 PDA and realizing that you remembered to put in your schedule for the day, but forgot to charge (or change) your batteries. Sharp Microelectronics says that it's addressing both of these challenges with its new LH79520 SOC. To reduce cost, Sharp made efforts to reduce total chip count by using things like an on-chip programmable color LCD controller. The LCD controller can drive a range of displays (STN, CSTN, TFT), including Sharp's Highly Reflective TFT (HR-TFT) and Advanced TFT (A-TFT) displays, which can push out up to 64K colors and up to 800x600 resolution. On the memory side, the flexible external memory interface can directly interface with SDRAM/SRAM/Flash and ROM memory devices. The LH79520 also provides a range of parallel and serial interfaces. To increase battery life, Sharp says the LH79520 balances performance (75MHz) with a low leakage current (5uA). A power management function also lets the chip run in a variety of power-saving modes. Depending on the performance needed, customers can set the system clock frequency via the PLL, and independently dial in the frequency of the peripherals or the CPU clocks to allow trade-offs in performance and power. Sharp says that Beta sites are using the device to power color mobile and multimedia applications like low-cost PDAs, medical data terminals, and marine displays. The company expects to have production quality samples in February 2002. Folks designing apps for the LH79520 will be able to draw from the pool of software development tool kits available for the ARM720T architecture the SOC is built on. When the LH79520 is relesed, Sharp will offer a development tool kit (hardware, software, documentation, application notes and evaluation copies of RTOS/OSes). Features of the LH79520 include a 32-bit ARM720T with an ARM7TDMI RISC core (75MHz), 8 kB instruction and data cache, a WinCE-enabled Memory Management Unit (MMU), 32 kB Internal SRAM; a programmable color LCD controller with 800x600 resolution, up to 64K direct colors, 15 gray shades, and support for STN, Color STN, HR-TFT, TFT and DMTN; an external memory interface to SDRAM, SRAM, Flash and ROM; 3 UARTs and synchronous serial communications interfaces; four-channel DMA, programmable interrupt controller, watchdog timer, four counters/timers, two pulse width modulators, real-time clock, and GPIO; and low-power modes including standby, sleep and stop. Maybe fewer chips with more programming flexibility are the way to go in reducing cost. We'll just have to wait and see how much cheaper devices get. Be optimistic.