Editing and adding programs on an HP15C

[Dave Britten]

I find a spreadsheet to be the biggest help when writing a very involved program. I'll often be keying things into Excel and the calculator simultaneously. You can even make little stack diagrams to the right of the program steps to verify your program logic. Once you've finished writing the program, keying it into the calculator, and testing it, you can go even further and put the numeric keycodes back into the spreadsheet for verifying correct entry in the future.

This approach is almost required for programming the 65, which doesn't have a BST key - you either have to loop all the way around with SST, or go back to RUN mode and hit RTN to go to the top. And it's still extremely helpful for any of the models that display numeric keycodes, i.e. nearly everything before the Pioneers (41C being the notable exception), as well as the 20S and 21S, which are Pioneers. Even the models with alpha instruction display can benefit from having a nice big multi-line work surface.

The 15C is about the upper limit of how long of a program I would want to enter with only numeric keycodes, no mass storage, and only the ability to delete one or all program steps. 15.2 mode in the 15C CE is nice, but that's an awful lot of program steps you can fill, and shuffling small programs in and out is not at all convenient, as you've noticed!