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Canon Canola L100A Electronic Desktop Calculator

The Canon Canola L100A is a very simple desktop calculator designed with one intent in mind...to provide a quality desktop calculator for the least money possible at the time. Canon had a reputation as a high quality calculator manufacturer, making machines that were overbuilt, using high quality parts, sturdy chassis materials, thicker plastic castings for cabinetry, and high quality switchgear. This dedication to quality back in the early 1970's meant that Canon calculators were typically somewhat more expensive than other manufacturer's calculators. In the market frenzy that developed in the 1972 to 1973 timeframe, the driving factor for success in the marketplace was cost. Handheld calculators were becoming more popular and accessable as a consumer device, driving the price point down, which also had a peripheral effect on driving down the cost of desktop calculators, which were mostly intended for business use. The L100A was Canon's 'high quality, but low cost' entry into the desktop calculator market for consumer use. It is about as 'bare bones' in terms of function that a calculator can get, yet still retains Canon's quality construction and 'feel'. With Texas Instruments, Commodore, and many others competing in this marketplace, Canon had a fine line to walk between maintaining their high quality, and keeping the price of their product competitive.

Profile View of Canon L100A

The Canon Canola L100A is about as basic a calculator as one can find. It provides ten digits of capacity (as opposed to eight digits of many of its competitors), and does only the four basic math operations. It has floating decimal point, and leading zero suppression. It does not have constant or roundoff capabilities. The calculator uses algebraic math rather than arithmetic math of many of its competitors, which may have been an indicator that Canon targeted the machine to the newly-created home/consumer market rather than the business market, as most business calculators use arithmetic logic.

Inside the Canon L100A

Internally, the L100A uses earlier chipset calculator technology, probably to leverage lower-cost IC's that were quickly being replaced by new single-chip LSI calculator designs. The machine uses a two-chip set for its brains. The Texas Instruments-made TMC1824 and TMC1825 Large Scale IC's provide the calculating grunt, combining forces with integrated display drivers (2-KH6248 and 1-KH6249) and a KH5305 chip used for clock generation.

The keyboard of the machine retains Canon's high quality reed-switch design. The keyboard plugs into the main circuit board with a 20-pin edge connector. The power supply of the machine is a very simple linear, transistor-regulated affair that takes up the area at the back of the cabinet.

The Unusual Planar Gas-Discharge Display Panel Used in the Canon L100A (Note Obscured Digit)

A planar-style display panel is used for the display, but is definitely not a Burroughs Panaplex design. Instead, the display seems to be a planar version of earlier discrete tube gas-discharge display technology. The display panel has twelve digit positions, but one of them (the neighbor to the right of the left-most digit) is covered with a piece of black cardboard glued to the display panel that obscures the digit from view. The digit needs to be hidden because there are artifacts of the fact that the IC's were intended to multiplex an eleven-digit panel, and the 'extra' digit flickers with random garbage while the machine is in operation. Rather than try to fix this electronically (perhaps Canon got a great deal on these 12-digit display modules!), the simple solution was to just cover the digit up so it wouldn't be seen by the user. The left-most digit is used for error and (sometimes) sign indication, with the remaining ten viewable digits are used for numeric display. Each digit is formed using standard seven-segment arrangement. Each digit in the panel contains a right-hand decimal point, along with a 'tick' at the upper left of each digit. The 'tick' is not used in this application.

Very Simple and Straightforward Keyboard Panel on the L100A

The L100A provides only the standard four math functions, using algebraic logic. The machine displays numbers right-justified, with leading zero suppression. If the number in the display is negative, a '-' appears in the digit position before the most significant digit in the number. If all ten digit positions are filled with significant digits, then the negative sign appears in the left-most digit position, one normally reserved for indicating an overflow condition. Should an overflow occur, the left-most digit shows an "E", and the rest of the display shows the most-significant 10 digits of the result. However, as opposed to most calculators, the keyboard does not lock up or attempt in any way to prevent the user from continuing calculations with the result -- any press of any key clears the overflow indication and places the decimal point at the right end of the displayed result, allowing calculations to continue. Division by zero results in a different indication, with right-justified "E0" showing up on the display. Again, pressing any key will clear this condition leaving the machine effectively cleared to begin a new calculation.

This machine was built in August of 1972, based on quality assurance tags inside the cabinet and various date codes.

The L100A is about average in terms of speed, with the "all nines divided by one" problem taking a little under 1/4 second. During calculation, the display is blanked.

Text and images Copyright ©1997-2011, Rick Bensene.