HP15C CE Finance Pac

[Divasson]

After Geoff Quickfall's wonderful Aviation Pac (for which we have ordered silicon overlays like the HP16c overlay), we said "why not a Finance Pac".

Finance programs for the HP15c are readily available, but are long, cumbersome to enter and prone to errors. We decided to put together some of the main ones and create a suitable overlay for them too.

Programs require at least 19 free registers and occupy 407 program steps. Finance Pac runs on 15.2 mode (so you need to set the calculator on 15.2 mode prior to upload the memory file). Programs in yellow in the overlay (on the keyboard surface) are launched by clicking on the function key (A to F) or GSB number. Programs in blue in the overlay (slanted part of the key) are launched by clicking GSB .number.

Time Value of Money: function keys A to F. Taken from the HP15c Advanced Functions book with a change to the error exit label code.

NPV: Up to 18 years + initial flow. Enter number of years in Reg. .9 ; initial cashflow in reg. 0; annual cashflows in registers 1 to .0; discount % in X; returns NPV in X. Own development

IRR: same registers as above; use f SOLVE .1 (NPV) - returns IRR in X

Weighted average: enter pairs of numbers with the statistics key: volume ENTER price Sigma, volume2 ENTER price2 sigma, ..., Renders sum of volumes in Y and weighted average of prices on X. Own development.

- Sales tax. (VAT in Europe) Introduce sales tax % in reg .8; gets value including tax from X; returns value before sales tax in X, sales tax in Y. Own development

+ Sales tax. Introduce sales tax % in reg .8; gets value before sales tax from X; returns value including sales tax in X, sales tax in Y. Own development.

MM.DDYYYY to Julian Day number. Taken from HPmuseum.org (15C) MM.DDYYYY or DD.MMYYYY to Julian Day [Stack-Only] from Nick

Julian Day number to MM.DDYYYY - Own development. Horrible programming, using registers! - you are welcomed to improve it.

DDAYS: difference between days in format MM.DDYYYY in X and Y. Taken from HPmuseum.org (15C) Delta Days [12C Actual Day Basis] from Nick. Uses MM.DDYYYY to Julian Day number

DATE+: date in Y in format MM.DDYYYY, increase in X. returns DATE+increase in MM.DDYYYY format. Own development. Uses Gregorian to Julian and Julian to Gregorian routines

Day of Week : enter date in MM.DDYYYY in X, returns day of week with Sunday=0, Monday=1; Saturday=6 - own development. Uses Gregorian to Julian subroutine. Thanks to Jukka Levänen who spotted a rounding error!

Pending: to document validity range of Gregorian date to Julian day number and Julian day number to Gregorian date.

You can find the Finance Pac and the documentation (thanks to Torsten Manz and his HP15c simulator!) here:

Finance Pac
Finance Pac documentation
Finance Pac Overlay preorder page



Overlay colors will be yellow for the surface of keyboard labels, white for the top of key labels, and blue for the slanted part of keys - just like the HP16c overlay.

Thank you for your feedback. As the HP15c is open, we can change the pac as needed and all improvements or corrections will be updated in the google drive site.