RPN-1250

[Benoit Maag]

Following the repurposing of the TI-1200 into the RPN-1200 RPN scientific calculator, I wanted to take the challenge of making a programmable version by repurposing the TI-1250, which is has the same enclosure and basic design as the TI-1200 but has an extra row of keys (6 rows instead of 5 for the TI-1200). The result is the RPN-1250 (see pictures)
   

The design is based on a 64kbyte flash Microchip PIC 18F2680 driving a MAX 7219 8-digit 7-segment LED driver. The software is programmed in C with the Microchip IDE MPLAB X.
   

Functionalities as below:

- 4-level stack RPN scientific with conversions
- 20 memories (0 to 9 and .0 to .9) with store and recall arithmetic
- All memories and stack can be saved to and recalled from the 'constant' flash memory of the PIC
- programmable 98 steps (like the HP-29C) with alphanumerical display of the program
- 3 programs can be saved to and recalled from the 'constant' flash memory of the PIC
- 20 labels (0 to 9 and .0 to .9), subroutines, all 12 tests, PAUSE and VIEW functions, SST execution
- Speed roughly 8X the HP-41C

What it does not have (vs HP-29C) is:
- ISZ/DSZ
- indirect addressing
- ABS function but this can be easily programmed as x<0? CHS
- Polar/Rectangular conversions (sorry Den)

There can easily be implemented but there are not any keys left to include them without complicating the UI - any suggestions?

Hope I will have a chance to show it to HHC 2016 !

Benoit