May 2009

New "Processor Power Manager" Reduces the Cost of Microprocessor Support

New ProcessorPM devices integrate the functions of separate power management ICs used in microprocessor and DSP designs; improved monitoring accuracy increases design reliability.

Lattice has announced a new member of its award-winning Power Manager II family, the ProcessorPM device, a programmable, single-chip solution for the reset generation, watchdog timer and voltage supervision functions found in virtually every microprocessor or DSP design. While priced competitively with off-the-shelf three-supply supervisor ICs, the ProcessorPM integrates the functions of reset generator ICs with variable pulse stretch timing, watchdog timer ICs running up to two minutes, and six-supply supervisor ICs.

The ProcessorPM reduces design costs by integrating functionality typically implemented using individual reset, supervisor and watchdog ICs. The ProcessorPM also provides greater design flexibility by incorporating Lattice’s in-system programmability.

ProcessorPM integrates multiple discrete chips.

The ProcessorPM device provides six programmable threshold comparators (accuracy -0.7%) with individual glitch filters to monitor up to six supply rails without using external resistors and capacitors. The comparator outputs are connected to a 16-macrocell, ruggedized on-chip PLD that generates reset and brownout signals by using simple logic equations. Four timers can be individually programmed from 32 microseconds to 2 seconds and used for implementing watchdog timers or for reset pulse stretching. Two digital inputs can be used for manual reset inputs or for monitoring other digital inputs such as Power Down or Disable Processor signals.

All device settings are stored using on-chip non-volatile EEPROM that is programmed via a JTAG interface. Design modifications after the board is assembled, such as changing thresholds or altering timer values, can be achieved easily by modifying the design in PAC-Designer software and then downloading it into the design through JTAG. There is no need to change any resistors or capacitors.

Factory Preprogrammed ProcessorPM Increases Convenience and Reduces Board Cost

ProcessorPM devices are preprogrammed with an initial configuration to integrate a programmable six-supply reset generator (configured through pin strapping) and a programmable watchdog timer (configured through pin strapping). This configuration can be used "as is" across a large number of designs. The original configuration software source code is also provided to enable integration of additional functions for further board cost reduction.

ProcessorPM Design Support

ProcessorPM designs can be implemented using the intuitive, user-friendly GUI provided in version 5.1 of the PAC-Designer software tool suite, which can be downloaded for free from the Lattice website.

PAC-Designer 5.1 software’s enhanced LogiBuilder capability enables designers to reduce their solution cost. The LogiBuilder requires 20 to 30% less PLD logic, enabling further integration of microprocessor support functions into the ProcessorPM device.

The ProcessorPM device can be customized for a given design environment in four simple steps:

1. Set up the monitoring thresholds. Using a simple pull-down menu, the supply fault detection thresholds for a given design can be set using 192 threshold steps for each of the voltage monitoring inputs. 
2. Configure the logic equation and timer delay setting to meet the reset pulse stretching, output polarity and selected supply monitoring using the intuitive LogiBuilder interface. 
3. Iterate through the design using the waveform simulator. 
4. Download the design into a Processor Power Manager evaluation board and verify the design in hardware before using it in schematic.

To Learn More

Visit the Lattice website or contact your local Lattice sales representative for additional information about the new ProcessorPM device.