Once upon a time, I wanted an programmable scientific calculator. In the following logs I'm going to explain how all the pieces interact with each other and how the behavior was defined. These are the main components used in the project. In the key 'B' a inverse function was coded. With the extra keys I added more functionalities like the '//' parallel (for impedance), '+-' change sign (unused), 'Fun' for functions and Enter. I also made a layout with paper and transparent tape, to know the meaning of each key and avoid noise on the exposed copper traces. The switch push button is 6圆mm and the pcb is 70x50mm.
I made a 6x4 matrix keyboard for this calculator. A pcb was made to adapt the smd pins to a "DIP" format. But it also has other interesting features, like SPI, USART, Timers, and Direct Memory Access (DMA) that I used in the graphics and the matrix keyboard. It has 64K bytes of flash memory and 8K bytes of ram. I used a stm32f030r8 as the main microcontroller. It's a simple ARM cortex-m0 with no floating point unit. And with two more GPIO the microcontroller was able to configure parameters like contrast and send all the graphics data.
#RPN SCIENTIFIC SERIAL#
It uses a SPI compatible serial communication protocol. It has 48x84 pixels, and if we use 8圆 pixel characters we end up with a display of 6x14 characters. That's why i choose the nokia 5110 lcd display. I considered using small 7 segment displays, but I couldn't get them because nobody in my area sold them, and I couldn't import them either.
#RPN SCIENTIFIC PLUS#
Lets start with the display, it had to be able to show a reasonable number of digits plus the signs, decimal point and exponent of scientific notation. There are other components like voltage regulators, battery chargers, on/off circuits but this project is focused only in building a calculator, it doesn't need to be standalone.
#RPN SCIENTIFIC MANUAL#
There’s even an in-app manual that features tutorial videos in case you’ve lost your touch." It uses the same Reverse Polish Notation entry system and supports the same mathematical functions. It mimics the look and feel of that classic number cruncher in every way possible. "Miss your old HP 11C RPN scientific calculator? Then give this utility app a try.
Cumulative statistical analysis & Linear regression.Index register for indirect operations.Factorial, absolute, integer & fractional.Probability (combinations and permutations).Hyperbolic and inverse hyperbolic trig functions.It uses the same RPN (Reverse Polish Notation) entry system and supports the same mathematical functions as the HP 11C Scientific Calculator. 11C Scientific Calculator is the most accurate and precise emulator of the HP 11C RPN scientific programmable calculator available for iPhone and iPod touch.
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