The fx-7000GA is a calculator manufactured by the Casio Corporation of Japan in approximately 1987. This calculator is identical to the fx-7000G in every respect apart from minor cosmetic differences. Both calculators have 82 scientific functions.
The graphic display consists of 63 dots by × 95 dots for plotting graphs; however, it is also organised to display 8 lines of text where each line may have a maximum of 16 characters.
From the image at the top, you can see the keyboard and the functions that are available, and the manual is the best place to learn more about them.
One of the interesting features of this calculator was the ability to express multi-statement functions manually and in program mode. This is where one may write multiple formulas or commands separated by colon symbols.
This calculator comes from a very long line of graphing calculators going all the way back to the earlier 6000 series such as fx-6000G, and fx-6500G that had graphing capability.
The 6000 series had 32 dots by × 96 dots display; however, the 7000 series has an extended vertical display of 63 dots. The 6000 series was the most ground breaking in terms of technology, and this was because of the advances in low power memory IC by Sanyo. This was also one of the earliest graphing calculators on the market placing Casio firmly in the lead.
The electronic engineering behind the 6000 and 7000 series was very similar, and the main calculator chip is almost identical based on CMOS technology. What makes the 7000G better is that it had a bigger LCD screen, which became possible due to the improvements in the Liquid Crystal Display (LCD) driver chips.
Programming Model / Language
The programming model is formula based with a mix of mnemonics for the conditional jumps and glyph symbols for variable assignment. The system architecture is Harvard based.
The programming storage space consists of a maximum of 422 steps, where each step occupies a byte of memory. The program area divides into ten sections P0 through P9. You could have ten independent programs in each storage space, or one main program with nine subroutines. The main program can then call these routines when required.
The flow of program execution is very important and for that, you have the familiar “GOTO” command, as one would find in the BASIC language.
For its time, it had a powerful programming language as it could also manage array-type memories, and pointers.
It is very easy to program this, as the language would be second nature to any programmer. Just for fun, I wrote a program for the delta-y transformation as this is something very easy to remember and it took just a few minutes.
I made some games, learnt how the memory space was organised, and wrote a program for displaying the Mandelbrot set. This is normally difficult to achieve in 422 bytes, but after hacking its memory, I was able to use the variable register space as well.
Physical Power Switch
An interesting design feature was this physical power switch to control the power to the calculator. This is why the batteries lasted as long as they did. On average, the three CR2032 batteries lasted two years (or 100 hours) depending upon usage of course.
Overall, it is a nice toy to play with, and if you like vintage technology, you can pick one of these up cheaply from places such as eBay. The current price for a fx-7000G is around a £10 if it has the original box and manual with it. The price of the fx-7000GA is also around the same; however, it depends on the auction day and the number of collectors bidding.
My First Programmable Calculator
I bought this calculator in 2004 at Cash Converters, and even then, it was ancient for its time.
I have always hated programmable calculators especially the ones that drew fancy graphs. I remember when I was in school, a rich kid brought one to class, and he was always showing off with it and fiddling with the buttons all day long. Of course, he had the entire brat pack of rich kids following him around. They were all middle-class, white, and into computers. They of course thought they were very superior destined for Cambridge, and I used to let them think so. However, I had the ZX81 at home and was programming in Z80 assembly language, but I was not going to tell!
I still remember my maths teacher in college advising us not to rely on graphics calculators too much. In Pure and Applied Mathematics, when you had to sketch a curve, the skill was in understanding the equation and being able to extract the necessary information such as points of intersection. Being able to understand where the curve intersected the x-axis and the y-axis, and finding the turning points provided a deeper insight into the equation.
Of course, these days you just enter the equation, and the calculator will plot it all for you and provide you with all the pertinent information. The average run of the mill student stopped using his brains two decades ago!
The one thing the teacher forgot to mention was that if you were to use your brains, then over time you could solve these equations faster in your head, than it would take to program the calculator!
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fx-7000GA Circuit Board
fx-7000GA CR2032 Batteries
fx-7000GA Main Chipset
fx-7000GA Back Cover and Reset Switch