Embedded Systems Design Europe - October 2007 - (Page 28) microcontrollers The proper use of an embedded MCU’s low-power/sleep modes is critical to a design’s success. MCU’s low-power modes Use an in foreground/background BY MIRO SAMEK systems n today’s world of battery-operated devices, the proper use of the low-power/sleep modes provided in most embedded microcontrollers (MCUs) is critical. At the same time, most high-volume MCU applications, such as home appliances, vending machines, motor controllers, and electronic toys, are organized as foreground/background systems (super-loops or main + ISRs). The foreground/background architecture consists of two main parts – the foreground comprises the interrupt service routines (ISRs) that handle asynchronous external events in a timely fashion, and the background is an infinite loop that uses all remaining CPU cycles to perform the less time-critical processing. The foreground typically communicates with the background through shared memory. The background loop protects this memory from potential corruption by disabling interrupts when accessing the shared variables. To employ a low-power MCU mode, the background loop must first determine that all external and internal events have been processed so that the CPU clock can be stopped until the next external event (an interrupt) will wake the CPU up. This situation is called the idle condition I 28 OCTOBER 2007 | embedded systems design europe | www.embedded.com/europe 028-029-030-031-032-033-034_ESDE28 28 10/10/07 11:37:06 http://www.embedded.com/europe
Table of Contents Feed for the Digital Edition of Embedded Systems Design Europe - October 2007 Embedded Systems Design Europe - October 2007 Contents Linux Set to Dominate Torvalds Updates Linux Kernel ARM Establishes Smart Card Foundry Program Emerson Buys Motorola's Embedded Comms Group LynuxWroks and TTTech to Cooperate on Avionics MontaVista CEO Looks for Acquisitions in Europe Ready: Multiprocessing Technology Provides Opportunity Automotive to Drive MCU Market New Supporters Join COM Express Group Analyst Weighs TI Versus Xilinx Versus PicoChip Cover Feature: Embedded Systems Security Has Moved to the Forefront Trace Exposes the Toughest Real-Time Bugs Employ a Secure Flavor of Linux Use an MCU's Low-Power Modes in Foreground/Background Systems Transporting Video Over Wireless Networks New Products Advertising Contacts Embedded Systems Design Europe - October 2007 Embedded Systems Design Europe - October 2007 - Embedded Systems Design Europe - October 2007 (Page 1) Embedded Systems Design Europe - October 2007 - Embedded Systems Design Europe - October 2007 (Page 2) Embedded Systems Design Europe - October 2007 - Contents (Page 3) Embedded Systems Design Europe - October 2007 - Contents (Page 4) Embedded Systems Design Europe - October 2007 - Contents (Page 5) Embedded Systems Design Europe - October 2007 - ARM Establishes Smart Card Foundry Program (Page 6) Embedded Systems Design Europe - October 2007 - ARM Establishes Smart Card Foundry Program (Page 7) Embedded Systems Design Europe - October 2007 - LynuxWroks and TTTech to Cooperate on Avionics (Page 8) Embedded Systems Design Europe - October 2007 - Ready: Multiprocessing Technology Provides Opportunity (Page 9) Embedded Systems Design Europe - October 2007 - Analyst Weighs TI Versus Xilinx Versus PicoChip (Page 10) Embedded Systems Design Europe - October 2007 - Analyst Weighs TI Versus Xilinx Versus PicoChip (Page 11) Embedded Systems Design Europe - October 2007 - Cover Feature: Embedded Systems Security Has Moved to the Forefront (Page 12) Embedded Systems Design Europe - October 2007 - Cover Feature: Embedded Systems Security Has Moved to the Forefront (Page 13) Embedded Systems Design Europe - October 2007 - Cover Feature: Embedded Systems Security Has Moved to the Forefront (Page 14) Embedded Systems Design Europe - October 2007 - Cover Feature: Embedded Systems Security Has Moved to the Forefront (Page 15) Embedded Systems Design Europe - October 2007 - Cover Feature: Embedded Systems Security Has Moved to the Forefront (Page 16) Embedded Systems Design Europe - October 2007 - Trace Exposes the Toughest Real-Time Bugs (Page 17) Embedded Systems Design Europe - October 2007 - Trace Exposes the Toughest Real-Time Bugs (Page 18) Embedded Systems Design Europe - October 2007 - Trace Exposes the Toughest Real-Time Bugs (Page 19) Embedded Systems Design Europe - October 2007 - Trace Exposes the Toughest Real-Time Bugs (Page 20) Embedded Systems Design Europe - October 2007 - Trace Exposes the Toughest Real-Time Bugs (Page 21) Embedded Systems Design Europe - October 2007 - Employ a Secure Flavor of Linux (Page 22) Embedded Systems Design Europe - October 2007 - Employ a Secure Flavor of Linux (Page 23) Embedded Systems Design Europe - October 2007 - Employ a Secure Flavor of Linux (Page 24) Embedded Systems Design Europe - October 2007 - Employ a Secure Flavor of Linux (Page 25) Embedded Systems Design Europe - October 2007 - Employ a Secure Flavor of Linux (Page 26) Embedded Systems Design Europe - October 2007 - Employ a Secure Flavor of Linux (Page 27) Embedded Systems Design Europe - October 2007 - Use an MCU's Low-Power Modes in Foreground/Background Systems (Page 28) Embedded Systems Design Europe - October 2007 - Use an MCU's Low-Power Modes in Foreground/Background Systems (Page 29) Embedded Systems Design Europe - October 2007 - Use an MCU's Low-Power Modes in Foreground/Background Systems (Page 30) Embedded Systems Design Europe - October 2007 - Use an MCU's Low-Power Modes in Foreground/Background Systems (Page 31) Embedded Systems Design Europe - October 2007 - Use an MCU's Low-Power Modes in Foreground/Background Systems (Page 32) Embedded Systems Design Europe - October 2007 - Use an MCU's Low-Power Modes in Foreground/Background Systems (Page 33) Embedded Systems Design Europe - October 2007 - Use an MCU's Low-Power Modes in Foreground/Background Systems (Page 34) Embedded Systems Design Europe - October 2007 - Transporting Video Over Wireless Networks (Page 35) Embedded Systems Design Europe - October 2007 - Transporting Video Over Wireless Networks (Page 36) Embedded Systems Design Europe - October 2007 - Transporting Video Over Wireless Networks (Page 37) Embedded Systems Design Europe - October 2007 - Transporting Video Over Wireless Networks (Page 38) Embedded Systems Design Europe - October 2007 - New Products (Page 39) Embedded Systems Design Europe - October 2007 - New Products (Page 40) Embedded Systems Design Europe - October 2007 - New Products (Page 41) Embedded Systems Design Europe - October 2007 - New Products (Page 42) Embedded Systems Design Europe - October 2007 - Advertising Contacts (Page 43) Embedded Systems Design Europe - October 2007 - Advertising Contacts (Page 44)
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