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RPN-duino
11-14-2015, 05:27 PM (This post was last modified: 11-14-2015 06:39 PM by Chasfield.)
Post: #15
RE: RPN-duino
I have just added another home-made scientific calculator to my RPN-duino stable. This one is completely scratch built, with the keyboard constructed from 30 miniature push switches. It uses a 4 line x 20 character back-lit LCD module and features two wholly visible, 4-line stacks. The left stack works in the usual RPN fashion. The right stack is used for:

carousel storage of pushed X register values
context switching - effectively a two channel calculator
applying arithmetic and slide rule functions simultaneously to multiple stored values

Referring to the top down photo:

Stack control features are implemented on the yellow buttons

Non standard ones are as follows:

CLL - clear left stack, CLR - clear right stack
PSH - push X register to right stack, POP - pop right stack to X register
SAV - image all of left stack to right stack, CPYX - pop right stack to X register with no right stack drop - preserve right stack
FLIP - exchange left and right stack contents - horizontal stack roll
2STK - stack function shift - applies square, square root, reciprocal or arithmetic functions, simultaneously, to all right stack elements

In amongst the blue keys is the 'SUMS' button, which totals the right stack and stores the result in the X register.

The display is split asymmetrically, with 12 characters for the left stack registers and 7 for the right. Column 13 delimits the stacks, with the top row character providing a place for shift annunciator symbols. The 'FLIP' key is convenient for viewing right stack contents in full available precision. Right stack values have an exponent indicator but don't display its value for want of space. Again, a press of the 'FLIP' key reveals the whole picture.

I programmed the display with two custom characters that prefix a number's exponent field and indicate its sign in one column to save space.

The keyboard top plate, bearing the key legends, is retained by magnetic strips and is removable.

The case is 11cm wide and large enough to hold a small packed lunch. It proves Chasfield's law of project enclosures - "an assembly expands to fill the casing available for it". I had hoped to run the whole show from AA batteries but ended up having to work hard to fit a PP3 in there. Current draw is around 30 mA, so that is fine.


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Messages In This Thread
RPN-duino - Chasfield - 10-16-2015, 03:55 PM
RE: RPN-duino - eried - 10-16-2015, 07:03 PM
RE: RPN-duino - David Hayden - 10-16-2015, 07:22 PM
RE: RPN-duino - Chasfield - 10-16-2015, 07:23 PM
RE: RPN-duino - Dwight Sturrock - 10-16-2015, 11:40 PM
RE: RPN-duino - eried - 10-16-2015, 08:50 PM
RE: RPN-duino - rprosperi - 10-16-2015, 09:23 PM
RE: RPN-duino - Chasfield - 10-17-2015, 04:38 AM
RE: RPN-duino - Thomas Klemm - 10-17-2015, 07:48 AM
RE: RPN-duino - rprosperi - 10-17-2015, 12:56 PM
RE: RPN-duino - Dwight Sturrock - 10-17-2015, 04:41 PM
RE: RPN-duino - Dave Frederickson - 10-17-2015, 05:02 PM
RE: RPN-duino - Vtile - 11-14-2015, 08:25 PM
RE: RPN-duino - walter b - 11-14-2015, 09:11 PM
RE: RPN-duino - Chasfield - 10-24-2015, 10:45 AM
RE: RPN-duino - ggauny@live.fr - 10-29-2015, 08:26 AM
RE: RPN-duino - vido - 09-18-2016, 06:50 PM
RE: RPN-duino - Chasfield - 11-14-2015 05:27 PM
RE: RPN-duino - Thomas Klemm - 11-14-2015, 05:48 PM
RE: RPN-duino - Chasfield - 11-15-2015, 10:28 AM
RE: RPN-duino - compsystems - 11-17-2015, 07:51 PM
RE: RPN-duino - Chasfield - 11-18-2015, 05:14 PM
RE: RPN-duino - Chasfield - 11-18-2015, 07:25 PM
RE: RPN-duino - Chasfield - 11-22-2015, 10:21 AM
RE: RPN-duino - Chasfield - 02-13-2016, 12:28 PM
RE: RPN-duino - Chasfield - 08-24-2016, 01:23 PM
RE: RPN-duino - Chasfield - 09-17-2016, 02:49 PM
RE: RPN-duino - larthurl - 04-06-2018, 02:29 PM
RE: RPN-duino - Luigi Vampa - 09-17-2016, 03:33 PM
RE: RPN-duino - Nigel (UK) - 09-17-2016, 06:57 PM
RE: RPN-duino - Chasfield - 09-18-2016, 01:52 PM
RE: RPN-duino - Nigel (UK) - 09-19-2016, 08:48 AM
RE: RPN-duino - Maximilian Hohmann - 09-19-2016, 09:44 AM
RE: RPN-duino - Chasfield - 09-19-2016, 02:35 PM
RE: RPN-duino - Luigi Vampa - 09-19-2016, 04:05 PM
RE: RPN-duino - jch - 09-19-2016, 07:08 PM
RE: RPN-duino - Chasfield - 09-28-2016, 03:24 PM
RE: RPN-duino - Chasfield - 09-28-2016, 05:01 PM
RE: RPN-duino - Luigi Vampa - 09-28-2016, 07:23 PM
RE: RPN-duino - Chasfield - 09-29-2016, 06:51 AM
RE: RPN-duino - Chasfield - 09-30-2016, 06:50 PM
RE: RPN-duino - Chasfield - 10-01-2016, 01:18 PM
RE: RPN-duino - Luigi Vampa - 10-01-2016, 03:20 PM
RE: RPN-duino - Chasfield - 10-01-2016, 03:31 PM
RE: RPN-duino - Chasfield - 10-01-2016, 05:39 PM
RE: RPN-duino - Luigi Vampa - 10-01-2016, 06:38 PM
RE: RPN-duino - Chasfield - 10-01-2016, 07:00 PM
RE: RPN-duino - Luigi Vampa - 10-02-2016, 09:14 AM
RE: RPN-duino - Luigi Vampa - 10-02-2016, 12:43 PM
RE: RPN-duino - Chasfield - 10-02-2016, 01:54 PM
RE: RPN-duino - Chasfield - 10-16-2016, 03:41 PM
RE: RPN-duino - Luigi Vampa - 10-16-2016, 07:49 PM
RE: RPN-duino - larthurl - 04-06-2018, 02:38 PM
RE: RPN-duino - Chasfield - 10-17-2016, 05:31 AM
RE: RPN-duino - Chasfield - 10-27-2016, 02:13 PM
RE: RPN-duino - Luigi Vampa - 10-27-2016, 08:27 PM
RE: RPN-duino - Chasfield - 10-28-2016, 01:20 PM
RE: RPN-duino - Chasfield - 03-25-2017, 03:02 PM
RE: RPN-duino - Luigi Vampa - 03-25-2017, 09:52 PM
RE: RPN-duino - Chasfield - 03-26-2017, 08:32 AM
RE: RPN-duino - Chasfield - 03-27-2017, 03:19 PM
RE: RPN-duino - Maximilian Hohmann - 03-27-2017, 03:58 PM
RE: RPN-duino - BobVA - 03-27-2017, 05:00 PM
RE: RPN-duino - Chasfield - 03-27-2017, 04:42 PM
RE: RPN-duino - Chasfield - 07-19-2017, 04:51 PM
RE: RPN-duino - Luigi Vampa - 07-19-2017, 05:26 PM
RE: RPN-duino - EugeneNine - 07-19-2017, 06:12 PM
RE: RPN-duino - Chasfield - 07-24-2017, 01:50 PM
RE: RPN-duino - Dan - 07-27-2017, 03:44 AM
RE: RPN-duino - larthurl - 11-28-2017, 09:11 PM
RE: RPN-duino - Luigi Vampa - 11-28-2017, 09:40 PM
RE: RPN-duino - Chasfield - 04-05-2018, 04:41 PM
RE: RPN-duino - Luigi Vampa - 04-05-2018, 04:44 PM
RE: RPN-duino - Luigi Vampa - 04-06-2018, 02:41 PM
RE: RPN-duino - Chasfield - 04-06-2018, 06:14 PM
RE: RPN-duino - Chasfield - 04-08-2018, 10:34 AM



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