NP-41 Emulator (may be)

[jch]

(01-26-2016 01:24 PM)J-F Garnier Wrote:  

(01-25-2016 07:33 PM)Chris Chung Wrote:  ... the display is of 132 x 32 pixels.

Great, it could be used to build a NP-71 (original HP71: 132 x 8 pixels plus annunciators)
:-)

Or even an HP-42S 131 x 16 pixels ;-)
But that's another and touchy topic.

(01-26-2016 01:00 PM)Chris Chung Wrote:  seems like I've opened up a can of worms (or candies)...
The original goal of the slim version is to create a lower cost HP-41 like machine so that I can carry around and play w/ FOCAL programming everywhere, plus I want something my kids can use in class and also a chance for them to explore RPN. And it can appeal to others who've never seen an RPN calculator before.

I am thinking of ways to squeeze the most juice out from the current design.

The 20K or so flash memory left unused can be used into ROM module storage of up to 4 x 4K rom modules (w/ compression 4K 10bit ROM takes 5Kbyte).

There are still 10+ GPIO lines I can used, so SPI, I2C, 2nd UART are all possible. Socket / slot for daughter board type expansion seems like a feasible idea.

The other options is to adopt a more capable MCU, something like 128K+ flash and 8K+ RAM. This will take longer as a lot of stuff need to start again.

I'm too lazy to check where I saw it, but a recent post stated something like 'one step at a time', and IMHO, NP-41, IS a major step, nice hardware design, 3D printed case & keys, expansion capabilities... Already a very serious calc ground.
I'm excited to get one.
Jean-Christophe