HP-42S "reinterpretation"

[jch]

Robert, In the design using the PIC32MX170F256B, do you intend to use EEPROM as 'virtual' firmware memory, copying chunks of code to RAM before running them or as calculator continuous storage ?

The ARM way will even be more easily achieved using an already soldered device, like Teensy 3.1.
It has half the memory than the ATSAM4LS8AA, but could be a good candidate for a trial run. It also has some RTC like counter.
Did you had a look to this lcd, it has the same horizontal resolution as the original.

How much flash will be needed to host the firmware ?
At first glance, emulation mode could make the best usage of a limited flash, but it will be harder to add functionalities.
On the other hand, a re-implementation like Free42 could allow more expandability, but the current code seems much larger than what a SOC can offer us.
Though this was achieved one year ago, (but before Free42 switched from BCD20 to Intel's Decimal Floating-Point Library ?)

(02-27-2014 08:28 AM)brouhaha Wrote:  And a further clarification. The DIY4, DIY4X, and DIY5 hardware that exists and has been shown at conferences etc. does not (yet) run WP-43s firmware, because the WP-43s firmware doesn't yet exist. Up to now, we've run microcode-level 41CX simulation (with some added features like 256 flags, and four-level stack display), and Thomas Okken's Free42 (modified for seven-level stack display).

I am curious about flash and RAM footprints...