AccuBalance Corp. AccuBalance

When Canon introduced in 1988 the Checkbook Recorder "Money Manager", it marked the eclipse of a series of Checkbook Calculators initiated already in 1975 with the Corvus 525 - better known as CheckMaster, brought to perfection with the National Semiconductor NS103A and brought to the masses with products like the Radio Shack EC-306 or TI 2200 II.

Fast forward and citing a patent application filed on December 2, 2003 by AccuBalance Corporation of St. Helena, CA:

AccuBalance Corporation was founded in November 2003 by Glenn Witherspoon in St. Helena, California with the clear mission to provide relief to millions of bank customers frustrated over the years with frequent checking account register errors and the dreaded end-of-the-month account reconciliation process. His extensive software development and Information Technology background, coupled with significant start-up and business development experience, provides the leadership and experience necessary to manage the development effort and bring AccuBalance to market.

Please find a press release of the U.S. Bank Market Trial with 1,000 AccuBalance units starting in September 2011 here.

The above mentioned "user device" was introduced in 2009 as AccuBalance, a Personal Digital Account Register, and it is pretty impressive! From the AccuBalance website, archived August 2009:

AccuBalance is finally here! A digital replacement for a paper register that fits in your checkbook wallet and keeps track of all account transactions, including debit card purchases, ATM withdrawals, checks, deposits, transfers, and fees. AccuBalance has touchscreen data entry, does all the math for you, and makes reconciling with your bank statement simple, quick, and accurate. No more overdraft fees! The number one recommendation for detecting unauthorized transactions and identity theft is to reconcile your account often. AccuBalance is easier to use than a calculator!

Architecture: Dismantling the AccuBalance manufactured in November 2010 reveals a modern architecture based on a NXP LH75411 microcontroller, formerly Sharp Microelectronics LH7xxx series, mounted in a low-profile quad flat pack package with 144 pins and powered by a single 3.3 V supply. Additional main components on the printed circuit board (PCB) are mostly memory devices and a USB to UART bridge. A second PCB provides the interface to the greyscale LC Display.

Processor: The The LH75411 is a 16/32-bit System-on-Chip (SoC) device centered around an ARM7TDMI-S core running at up to 84 MHz and completed with 32k Bytes SRAM, Touch Screen Controller, 3 Serial Interfaces (UART), Real-Time Clock, 3 Counters and Timers and a Color and Greyscale LCD Controller.

Memory: The AccuBalance makes use of two different memory chips:

• NOR Flash-ROM
• SRAM

Flash memory is non-volatile and does not need a battery to maintain the information stored in the chip. In the past years two different technologies emerged in parallel with some advantages and disadvantages.

The NOR Flash-ROM was invented by Toshiba in 1984 and found its way immediately as a replacement of the more expensive ROM (NRE mask costs) and EEPROM (device costs) memory. The NOR Flash-ROM's use an address and data bus to allow the random access to any memory location. Main disadvantages of the NOR Flash-ROM compared to the NAND Flash-ROM are the higher costs, larger housings and slower write speeds.

The disassembled AccuBalance makes use of one M29W160EB, manufactured by STMicroelectronics, with a selectable 1M*16 or 2M*8 (2M Bytes) organization.

SRAM is the abbreviation of static random access memory and is used as program and data memory for microprocessor systems.