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Welcome to my little shop of art and stuff where everything is free for non-commercial use. In case you find something useful proper credit will be greatly appreciated. I am an occasional hobbyist in the field of drawing/painting and somewhat more active in electronics. Both aspects are presented in the following pages.
The Art Gallery features experiments using ballpoint pens, dry media and some oil paint.
The Electric Circuits page lists a number of excerpts, mostly elementary and others partly drawn from earlier work in the field of analog electronics that overall might be of some educational value.
The DemCalc machines are more recent in the line of computers.They are based, in one form or another, on RPN structures and especially for the DemCalcProg implementation the core supports nested expressions and control structures using recursion. Use IDE 1.8.13 to compile the source.
The DemUino machines are no longer supported.
Nick Gammon's High-voltage programmer for AVR chips
Recover your bricked atmega328p by changing the fuses.
Note:
If you don't have available a p-mosfet for the RESET circuit you can use a PNP BJT such as the complementary of 2N3904 - the 2N3906 - driven with a 10K or smaller resistor from the collector of 2N3904 to its base. The small resistor will ensure saturation of the CE junction; also, you will need a load of a few KOhms (I used 2.2K - use 3.3K,4.7K etc) from its collector to GND. Its collector also connects to the RESET pin of the target.
Instead of the 2N3904-6, I used a pair of BC546-BC556 BJT transistors.
STACK BASED RPN SCIENTIFIC CALCULATORS
COMMON HARDWARE
atmega328p @ 4MHz
8 x 7-segment leds
User defined system settings.
coin cell battery operation
Low battery drain <2mA min.
Auto shutdown less than 1uA
DemCalcProg5
Programmable RPN Calculator - version 2.87h
comprehensive programming model with dynamic buffers, user defined variables with resizable strings
Programmable expressions based on avr-libc functions
Single key operators plus explicitly typed commands using alphabet and symbols
Extensive programming using floats and control structures.- more than 80 operators
RPN stack based math and functionality with variable stack depth and tokens, user defined variables, global and local variable use as well as parameter passing to executing programs
Dynamic program allocation with variable length strings using linked list and nested RPN expressions and loops to memory limit.
User defined variables with arrays and auto resized strings using linked list.
1450 bytes free by default for programming expressions (dynamic buffers in version 2)
scientific notation only.
Integration, Derivative, Transfer Function computation in s/zdomains, DFT and convolution.
use EEPROM for programs and data with program allocation table
User defined fonts and system settings.
5 calculator key maps + 3 auxiliary for letters A...Z and symbols
Use IDE 1.8.13 for compiling.
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DemCalcBC
Arbitrary Precision RPN Calculator
ver 6a
A total of 5 key maps - single key operation - 1450 bytes free RAM
BigNumber and avr-libc functions.
Scientific and programmer's operations.
Stack based functionality with X,Y, Z & T registers.
Standard and scientific notation.
Brief visual mnemonic for all operators
Standard notation for BigNumbers up to 50 digits..
User defined system settings.
Low battery drain operating with 2mA min. for hw3
Auto shutdown to less than 1uA for hw3
Use IDE 1.8.13 for compiling.
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DemCalc64
Double Precision RPN Calculator
ver 3.0
A total of 5 key maps
A mixture of both fp64 and avr-libc functions.
Scientific and programmer's operations.
Stack based functionality with X,Y, Z & T registers.
Standard and scientific notation for fp64 numbers up to 17 significant digits.
Brief visual mnemonic for all operators
Transfer function in s and z domains, convolution and DFT using standard floats.
User defined system settings.
Low battery drain operating with 2mA min. for hw3
Auto shutdown to less than 1uA for hw3
Use IDE 1.8.13 for compiling.
Programmable fonts used by DemCalcProg machines
A 0 49 (1 A * SIN d[A] =) FOR
d[A 51 -] d[A 50 -] + 1 T - d[A 1 -] * - 1 T + / d[A] =
1 CmpCalc_PICO
SCIENTIFIC RPN CALCULATOR v1.21
with native support for complex numbers and BigNumbers
FEATURES
Based on raspberry pi pico, a 2x16 LCD text display, a 4x4 keypad, an SD card interface and rechargeable batteries.
Calculator (real numbers) and Programming (complex numbers) modes. Use .. to switch from PRG to CAL and back to PRG mode. A total of 8 calculator key maps including letters A...Z and symbols. RPN functionality with variable stack depth and number of tokens. User defined strings, variables and functions. Nested expressions to memory limit. Math functions with real and complex numbers using double precision floating point arithmetic as well as support for BigNumbers. Integration (line integrals), Derivative, Transfer Function computation in s/z/real domains, DFT and convolution. LittleFS (flash) as well as SD functionality for storing / recalling programs and data. Optional EEPROM FAT. Music playback of 8-bit mono .wav files.
Standard and scientific notation. Complex numbers support in both real and native mode. User defined system settings.
Low battery drain operation with 18mA nominal at VSYS=3.6V and 50MHz MCU clock speed.
If you have comments or questions you can either contact me at biromaster@yahoo.com or if you have a google account you can first sign in and then leave a comment at the bottom of the corresponding page.
Thanks for visiting and I hope you enjoy your stay.