16-Bit Microcontroller From Maxim Extends Battery Life in Portable Equipment

To further prolong battery life, the MAXQ610 consumes an ultra-low 200nA (typ) in stop mode, and delivers up to 12MIPS at 3.75mA (typ) in active operation. In all, the device can lengthen the life of batteries by several months.

The MAXQ610 is an integrated, low-cost solution that simplifies the design of low-power applications. The microcontroller includes two USARTs, an SPI(TM) master/slave communication port, dual 16-bit timers, an 8kHz wakeup timer, and up to 38 general-purpose I/O pins capable of supporting an electromechanical or capacitive-touch keypad matrix. Additionally, the MAXQ610 provides a secure memory management unit (MMU) to prevent device cloning and unauthorized access to sensitive application code.

The MAXQ610 is ideally suited for battery-powered equipment such as sensors, universal remote controls, meters, and data loggers.

Manufacturers of battery-powered devices can reduce the environmental impact of their products by utilizing low-power microcontrollers that can extract every available milliwatt of power from batteries.

Battery-powered systems must operate over a very wide voltage range to support battery technologies with different minimum operating voltages. For example, AA batteries reach end of life at approximately 0.8V per cell, or 1.6V for two AA cells. However, most 8- and 16-bit microcontrollers on the market today only operate down to 2.0V, leaving as much as 20% of the battery capacity unused.

The MAXQ610 solves this problem by operating down to 1.7V, which allows the device to utilize 95% of the battery capacity. Effectively increasing battery life by up to 15% over conventional solutions, the device extends operation by several months in many applications.

In addition to improved battery-capacity utilization, the MAXQ610 offers advanced power-saving modes to further extend battery life.

Many low-power applications spend the vast majority of their time in stop mode, only waking up periodically to perform a required function. With a glucose meter, for example, the user may take readings several times a day, with each reading taking less than a minute. In this case, the device may be in stop mode for as much as 98% of the day. A competitive microcontroller that consumes 5mA when running and 1microamp in stop mode would have an average current consumption of: (2% x 5mA) + (98% x 1microamp) = 101microamps. At 101microamps, two heavy-duty AA batteries rated at 1000mAh total would last about 1.1 years. In contrast, the MAXQ610 consumes 3.75mA when active and 200nA in stop mode, effectively increasing battery life to approximately 1.5 years.

Stop-mode options on the MAXQ610 give the designer the flexibility to switch to a low-power regulator during stop mode, turn off the power-fail monitor, and generate wake-up events from external inputs or from an internal ultra-low-power, programmable 8kHz timer. When exiting stop mode, the power-fail monitor verifies that system power has stabilized before it allows the microcontroller to execute code. If the system power is below the minimum operating voltage (< 1.7V), the MAXQ610 goes into a power-checking mode until the voltage returns to above 1.7V.

At the heart of the MAXQ610 is a high-performance, MAXQ RISC core. This proprietary architecture offers the industry's best MIPS/mA rating, allowing designers to achieve the same performance as competing microcontrollers but at substantially lower power.

The MAXQ core delivers an optimum performance-to-power ratio by maximizing clock-cycle utilization for user-code execution. Unlike competitive architectures, the MAXQ core executes nearly all instructions in a single clock cycle. This capability increases instruction bandwidth and allows designers to reduce clock frequency. By distributing clocks to only those circuits that require clocking at any instant, this architecture minimizes power consumption as well as noise that can affect sensitive analog circuits.

All of these power and performance enhancements give industrial and commercial equipment a competitive advantage; however, it is critical to protect an application's IP in order to maintain this advantage.

The MAXQ610 provides multiple levels of security to assist developers with protecting their IP. With a user-definable scrambling key, the MAXQ610 stores application code in an obfuscated format, increasing the difficulty of reverse engineering. In addition, a unique customer-assigned application key can be programmed into the MAXQ610 during manufacturing. This key allows a customer's application code to validate against the MAXQ610 hardware and prevent code execution if the validation fails.

For rapid application development, a MAXQ610 evaluation (EV) kit is available. Providing both the microcontroller evaluation platform and all necessary software, the kit seamlessly connects the microcontroller's onboard boot loader and debugging features with PC-side software to communicate with an integrated development environment. Options for application development include a free assembly project development environment (MAX-IDE), Rowley CrossWorks IDE, and the IAR Embedded Workbench(R) for MAXQ (available in time-limited or code-limited versions for free product evaluation). An integrated JTAG-compatible debug port on the MAXQ610 provides hardware-based in-circuit debugging and programming support for both C and assembly-based applications.