Nuts and Volts - May 2014

It can send the operators plus some special ones like Pi, the EE key, and a few others. Again, anything not found here can be sent by using sendCmd. This option is not recommended and may be eliminated. Use sendANstring instead.

I did not make the parser complete because the library is already over 16K if fully used, which is about half the Uno's code space. If you need more, you can easily modify the library.

A few other routines are Enter() to send the "enter" key; clearScreen(); getDir() which gets a directory of the variables stores in the calculator and prints them to the serial monitor; and getStatus() which gets the status (and identity) of the calculator.

Finally, floatout corrects a defect in the Serial.print routine to handle floating point numbers correctly; comp holds the code used by the computer to send instructions and helps distinguish between the 86 and the 83+/84+ which use the same code.

Graphic commands can usually be sent by sendANstring or sendCmd if needed, or a combination of both — one of the examples at the article link shows this.

Plotting can be done via the Plot command. Lists can be sent as well, so statistics may be processed on them.

There are six example programs included in the available library. The first shows how to use the constructor (see Figure 3). There are examples of sending data and calculating math, as well as a demo of some of the functions. The last examples 5 and 6 draw a circle and plot data (Y vs X where Y=X^ 2).

Figure 4 is a screenshot of the plot (y=x^ 2) from example 6. The code that produced it is in Figure 5.

The final example ( 7) shows a case where two calculators are controlled at the same time (you can control as many calculators as you have pins for). Since this is really C++, we can create two instances of

Arto TI and deal with each instance separately. Obviously, you need two each of calculators, cables, and resistors, but at least you know that if you need this feature it is available.

For improvements, the parser can be expanded and lists can be sent via silent transfer. Currently, I cannot get it to work, so they are sent as keystrokes. If anyone can send the lists silently, I would like to see the protocol they are using. Finally, I am considering adding the 89.

I hope this library allows people to make use of these fine calculators in a new way! NV

May 2014 51

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