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Benoit Maag · 09-27-2015, 06:17 PM

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

Harald · 09-27-2015, 08:40 PM

Very nice! Is the software open source?
Might be tempted to make an RPN-1250 myself then Smile

Jonathan Cameron · 09-27-2015, 09:42 PM

(09-27-2015 06:17 PM)Benoit Maag Wrote: 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)

<snip>

Benoit

Nice going Benoit! I look forward to seeing it!

-Jonathan

matthiaspaul · (This post was last modified: 09-28-2015 02:11 AM by matthiaspaul.)

(09-27-2015 06:17 PM)Benoit Maag Wrote: 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?

The original layout (as far as I could decipher it on the photo):

Code:

GTO   BST   SST   R/S

GSB   LBL   SV    PSE

RTN   TST   LD    VIEW

      PRGM  CHS   /

F     IP    EEX   FIX

G     FP    NOP   SCI

7     8     9     *

SIN   COS   TAN   STO

ASIN  ACOS  ATAN  RCL

4     5     6     -

LN    LOG   SQRT  x<>y

e^x   10^x  x^2   Rv

1     2     3     +

1/x   in>mm mi>km lb>kg

y^x   mm>in km>mi kg>lb

<     0     .     ENTER

CLR   pi    F>C   LASTx

ALL   >DRG  C>F

I took the freedom to rearrange some keys in order to add some of the missing functions. My suggestion would be as follows:

Code:

GTO   BST   SST   <

GSB   LBL   SV    CLR/A

RTN   TST   LD    PRGM

R/S   1/x   CHS   ENTER

F     Rv    x<>y  LASTx

G     SCI   FIX   VIEW

7     8     9     /

SIN   COS   TAN   RCL

ASIN  ACOS  ATAN  STO

4     5     6     *

LOG   LN    SQRT  y^x

10^x  e^x   x^2   |x|

1     2     3     -

in>mm mi>km lb>kg F>C

mm>in km>mi kg>lb C>F

0     .     EEX   +

PSE   IP    pi    P>R

NOP   FP    >DRG  R>P

- Combined R/S run/stop and F/G modifiers to something like F/G/R/S. Normal function is as F/G modifier, but if pressed three times in a row, it will work as R and run the program. In a running program, pressing the key will work as S, that is, stop the program. This will make it work as F/G modifier again.
- Combined CLR and ALL. First F+CLR will invoke "Clear", either F+CLR+< (or F+CLR immediately followed by F+CLR again) will invoke "Clear All".
- Added P>R and R>P functions
- Added |x| function
- Rearranged some assignments for an IMHO more logical, easier to memorize layout and more convenient usage (although various compromises had to be made given the very limited number of keys):

- EEX directly invocable and part of the numpad
- pi is often on the same key as EEX
- IP/FP are semantically related to decimal points
- PSE is often on same key as 0
- RCL is used more often than STO
- Operations 1/x and +/- are frequently needed and typically located close to Enter
- Rv and x<>y are frequently needed stack manipulations and should be easily accessible
- LOG and 10^x in same column as 1 for mnemotical reasons
- LN and e^x in same colum as 2 for mnemotical reasons (e=2...) (Another possible order instead of LOG/LN/SQRT could be SQRT/LN/LOG, but it would not group SQRT near y^x.)
- Enter key above op keys, not below them. This makes the four op keys line up nicely with the numpad
- Delete (<) in upper right corner

Greetings,

Matthias

Benoit Maag · 09-28-2015, 02:36 AM

(09-28-2015 02:01 AM)matthiaspaul Wrote:
(09-27-2015 06:17 PM)Benoit Maag Wrote: 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?
The original layout (as far as I could decipher it on the photo):

Code:

GTO BST SST R/S GSB LBL SV PSE RTN TST LD VIEW PRGM CHS / F IP EEX FIX G FP NOP SCI 7 8 9 * SIN COS TAN STO ASIN ACOS ATAN RCL 4 5 6 - LN LOG SQRT x<>y e^x 10^x x^2 Rv 1 2 3 + 1/x in>mm mi>km lb>kg y^x mm>in km>mi kg>lb < 0 . ENTER CLR pi F>C LASTx ALL >DRG C>F
I took the freedom to rearrange some keys in order to add some of the missing functions. My suggestion would be as follows:

Code:

GTO BST SST < GSB LBL SV CLR/A RTN TST LD PRGM R/S 1/x CHS ENTER F Rv x<>y LASTx G SCI FIX VIEW 7 8 9 / SIN COS TAN RCL ASIN ACOS ATAN STO 4 5 6 * LOG LN SQRT y^x 10^x e^x x^2 |x| 1 2 3 - in>mm mi>km lb>kg F>C mm>in km>mi kg>lb C>F 0 . EEX + PSE IP pi P>R NOP FP >DRG R>P
- Combined R/S run/stop and F/G modifiers to something like F/G/R/S. Normal function is as F/G modifier, but if pressed three times in a row, it will work as R and run the program. In a running program, pressing the key will work as S, that is, stop the program. This will make it work as F/G modifier again.
- Combined CLR and ALL. First F+CLR will invoke "Clear", either F+CLR+< (or F+CLR immediately followed by F+CLR again) will invoke "Clear All".
- Added P>R and R>P functions
- Added |x| function
- Rearranged some assignments for an IMHO more logical, easier to memorize layout and more convenient usage (although various compromises had to be made given the very limited number of keys):

- EEX directly invocable and part of the numpad
- pi is often on the same key as EEX
- IP/FP are semantically related to decimal points
- PSE is often on same key as 0
- RCL is used more often than STO
- Operations 1/x and +/- are frequently needed and typically located close to Enter
- Rv and x<>y are frequently needed stack manipulations and should be easily accessible
- LOG and 10^x in same column as 1 for mnemotical reasons
- LN and e^x in same colum as 2 for mnemotical reasons (e=2...) (Another possible order instead of LOG/LN/SQRT could be SQRT/LN/LOG, but it would not group SQRT near y^x.)
- Enter key above op keys, not below them. This makes the four op keys line up nicely with the numpad
- Delete (<) in upper right corner

Greetings,

Matthias

Matthias,

Thank you for the suggestions ! I will look into that.

BTW, there were a few things tha are not visible on the keyboard:
- pressing F/G 3 times currently loops back to no prefix (CLEAR-PREFIX) - maybe I can use NOP as the CLEAR-PREFIX option, or as R/S.
- G-ENTER actually calls an Escape Mode where the display brightness can be adjusted, the version of the software can be displayed and so on. So I would need a way to get there.

Benoit