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Memory/RTCC Technology

High Endurance Serial EEPROM and Serial SRAM Memory

Since data storage is a critical factor, a reliable memory such as a serial EEPROM has been the industry preference for many years. The 24xxx and 25xxx serial EEPROM devices support an I²C and SPI serial interface respectively. Further details at www.microchip.com/memory.

Flash Memory

For applications with higher density memory requirements, Microchip’s NOR flash memory products with patented and proprietary SuperFlash® nonvolatile flash memory cells are an ideal solution. SuperFlash memory uses a split-gate cell design and a thick-oxide tunneling injector to offer significant cost and reliability benefits to customers. Superior reliability of 100,000 cycles endurance and greater than 100 years of data retention ensures robust and reliable designs for meter applications. Small Sector Architecture enables a system to choose the right amount of data/code to be erased to update contents allowing seamless partition of program and data code occupying less memory space.

Microchip offers multiple interfaces to satisfy different design needs; Parallel Flash offers asynchronous random access through dedicated address bus. SQI™ flash memory reads and writes through a 4-bit multiplexed synchronous serial communication interface enables true low-pin count, high-bandwidth code execute-in-place applications. SPI Flash serial interface is a cost effective option to store the boot loader code, making it available for download into shadow memory upon power-up.

Memory Cell Structure

  • No over-erase problem
  • Low total power consumption during erase
  • Low leakage current during erase
  • Small sector architecture
  • Faster re-write times
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Real-Time Clock/Calendar

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885x365_MCP795XXSPIRTCCFeatures

Integration

The MCP794XX and MCP795XXX low-power real time clock/calendar devices feature non-volatile memory and can operate down to 1.3V through the backup supply connected to the VBAT input for timekeeping and SRAM retention only. As part of the power sense circuit, a time saver function is implemented to store the time when main power is lost and again when power is restored to log the time and duration of any power failure. A Watchdog Timer is included for applications outside the microcontroller.

Accuracy

Accuracy is needed over a wide temperature range; these RTCC devices were implemented with digital trimming to support a software temperature- compensated design. Through the use of an MCU and an external temperature sensor, the digital trimming registers can be updated with new calibration parameters when the temperature changes.

Unique ID

A 64-bit or 128-bit protected EEPROM space is available for a unique ID or MAC address to be programmed at the factory or by the end user.

Anti-Temper

To support anti-tampering requirements, two types of digital event detects were implemented in the MCP795XXX RTCC. One event detect input is high speed with a programmable pulse count that can identify the 1/4/16/32 pulses before sending an interrupt the MCU. The second event detect is low speed with a built-in debounce input filter to support noisy mechanical switches or the removal of a panel from the meter. Since the real-time clock is running all the time, the event detects operate all the time.

Learn more at www.microchip.com/RTCC.

Metering Video Channel