Re: Finally a PIC32 with FPU for embedded Lua on MIPS

The new Cortex-M7 from ARM supports double precision FPU as an implementation option too:

http://www.bdti.com/InsideDSP/2014/09/25/ARM

We just need to wait a bit for the chips to appear. Also, double-precision FPU existed on Cortex-R parts for a while now, see for example http://www.ti.com/mcu/docs/mcuproductcontentnp.tsp?sectionId=95&familyId=2056&tabId=2841&DCMP=hercules&HQS=hercules-rm4x-pr-pf.

Indeed, the Microchip parts have an impressive amount of on-chip RAM, which definitely makes them suitable for Lua. I've looked at porting eLua to these for a while, but every time I got put off by various licensing issues with Mircrochip's not-exactly-open-source tools and libraries. Too bad.
In any case, things are looking good for Lua on this front :)

On Fri, Jan 9, 2015 at 12:54 PM, KHMan <keinhong@gmail.com> wrote:

Hi all,

A bit of good news for embedded Lua users, specifically on the topic of Lua on a MIPS chip :-)

A PIC32MZ EF Family data sheet recently popped up on Microchip's data sheet RSS feed [1]. FPU on the chip finally! No official announcement yet, and it's not in the PIC32 parts table, so probably no customer samples etc yet. It's just a data sheet drop before PR releases, advance info, but I think we should be able to buy it this year.

So finally there will be a MIPS part that can run standard Lua with floating point hardware, and minimal source code changes, and can be easily purchased by normal folks [2]. For those who don't want to peruse the data sheet, it's 200MHz, up to 512KB SRAM [3] and up to 2MB flash on chip. FPU throughput is mostly 1 cycle, latency for ADD/SUB is 4/5 cycles. Downside: the errata doc for its predecessor PIC32MZ EC family was very long...

[1] http://www.microchip.com/RSS/Recent-DataSheets.xml
[2] there is Ingenic, but it's kinda hard to source
[3] a goodly amount of RAM for Lua on an easily solderable TQFP (everything else with >=512KB SRAM on Farnell is a BGA part)

--
Cheers,
Kein-Hong Man (esq.)
Kuala Lumpur, Malaysia