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Preliminary

Processor Companion FM3316 - 33928 FM33256/FM3316

3V Integrated Processor Companion with Memory Features

Processor Companion High Integration Device Replaces Multiple Parts • Active-low Reset Output for V
DD and Watchdog • Serial Nonvolatile Memory • Programmable Low-V
DD Reset Thresholds • Real-time Clock (RTC) with Alarm • Manual Reset Filtered and Debounced • Low V
DD Detection Drives Reset • Programmable Watchdog Window Timer • Watchdog Window Timer • Nonvolatile Event Counter Tracks System Intrusions or other Events • Early Power-Fail Warning/NMI • 16-bit Nonvolatile Event Counter • Comparator for Power-Fail Interrupt or Other Use • Serial Number with Write-lock for Security • 64-bit Programmable Serial Number with Lock Ferroelectric Nonvolatile RAM Fast SPI Interface • 256Kb and 16Kb versions • Up to 16 MHz Maximum Bus Frequency • Unlimited Read/Write Endurance • RTC, Supervisor Controlled via SPI Interface • 10 year Data Retention • SPI Mode 0 & 3 (CPOL, CPHA=0,0 & 1,1) • NoDelay™ Writes Easy to Use Configurations Real-time Clock/Calendar • Operates from 2.7 to 3.6V • Backup Current under 1 µ A • Small Footprint “Green” 14-pin SOIC (-G) • Seconds through Centuries in BCD format • Low Operating Current, 50 µ A Standby Current • Tracks Leap Years through 2099 • -40 ° C to +85 ° C Operation • Uses Standard 32.768 kHz Crystal • Software Calibration • Supports Battery or Capacitor Backup

Description

The FM33256 and FM3316 are devices that integrate F-RAM memory with the most commonly needed functions for processor-based systems. Major features include nonvolatile memory, real-time clock, low-V
DD condition or a watchdog timeout. /RST goes active when V
DD drops below a programmable threshold and remains active for 100 ms (max.) after V
DD reset, watchdog timer, nonvolatile event counter, lockable 64-bit serial number area, and general purpose comparator that can be used for a power-fail (NMI) interrupt or other purpose. The devices operate from 2.7 to 3.6V. Each FM33xx provides nonvolatile RAM available in memory capacity of 16Kb and 256Kb. Fast write speed and unlimited endurance allow the memory to serve as extra RAM or conventional nonvolatile storage. This memory is truly nonvolatile rather than battery backed. The real-time clock (RTC) provides time and date information in BCD format. It can be permanently powered from external backup voltage source, either a battery or a capacitor. The timekeeper uses a common external 32.768 kHz crystal and provides a calibration mode that allows software adjustment of timekeeping accuracy. The processor companion includes commonly needed CPU support functions. Supervisory functions include a reset output signal controlled by either a low V
DD rises above the trip point. A programmable watchdog timer runs from 60 ms to 1.8 seconds. The timer may also be programmed for a delayed start, which functions as a window timer. The watchdog timer is optional, but if enabled it will assert the reset signal for 100 ms if not restarted by the host within the time window. A flag-bit indicates the source of the reset. A comparator on PFI compares an external input pin to the onboard 1.5V reference. This is useful for generating a power-fail interrupt (NMI) but can be used for any purpose. The family also includes a programmable 64-bit serial number that can be locked making it unalterable. Additionally it offers an event counter that tracks the number of rising or falling edges detected on a dedicated input pin. The counter can be programmed to be non-volatile under V
DD power or battery-backed using only V
BAK . If V
BAK is connected to a battery or capacitor, then events will be counted even in the absence of V
DD .
This is a product that has fixed target specifications but are subject Ramtron International Corporation to change pending characterization results. 1850 Ramtron Drive, Colorado Springs, CO 80921 (800) 545-FRAM, (719) 481-7000 Rev. 1.1 http://www.ramtron.com Dec. 2007 Page 1 of 28