[squeak-dev] 16 bit Squeak (was: 5.2 alpha test results: VM 201807260206 & trunk image - Windows 7 32-bit)

Ben Coman btc at openinworld.com
Wed Aug 1 01:45:44 UTC 2018


On 1 August 2018 at 07:05, Jecel Assumpcao Jr. <jecel at merlintec.com> wrote:
> Tim Rowledge wrote on Sun, 29 Jul 2018 14:20:11 -0700
>> > On 29-07-2018, at 1:50 PM, Eliot Miranda wrote:
>> > A particular case where this applies is Internet Of Things size devices.
>> >
>> > A 16-bit version would be killer.  What 16-bit processors are doing well
>> > in the market these days, if any?
>
> I think that the TI MSP430 is the most popular 16 bit processor.
>
> https://en.wikipedia.org/wiki/TI_MSP430

>From that page, maximum RAM seems to be 10K and max speed 25MHz.
Although here shows an $18 chip with 32KB of RAM.
https://www.digikey.com.au/products/en/integrated-circuits-ics/embedded-microcontrollers/685?FV=23c0026%2C1f140000%2Cffe002ad&quantity=&ColumnSort=-1000011&page=1&k=MSP430&pageSize=25&pkeyword=MSP430


Coincidentally I recently researched some ESP32 devices...
https://www.mouser.com/Search/Refine.aspx?Keyword=esp32+rover
$4.20  240MHz ESP32 WROVER 8MB SRAM, 4MB Flash
$5.00  240MHz ESP32 WROVER 8MB SRAM, 16MB Flash (seems a new product,
lead time 8 weeks)

Now I guess that most of the cheaper third-party (non-Espressif)
boards use the WROOM that only have 512KB SRAM,
but the extra SRAM of the WROVER will require less trimming of the Image.
Background info on ESP32 Modules and Boards
https://dl.espressif.com/doc/esp-idf/latest/hw-reference/modules-and-boards.html
and further here
http://esp-idf.readthedocs.io/en/latest/hw-reference/modules-and-boards.html

The ESP-WROVER-KIT V3 seems a useful host system for VM porting work.
Useful features...
  1. JTAG debugging interface may help VM development
  2. MicroSD card slot for quickly switching between test systems and
expanded memory
  3. LCD screen might facilitate Morphic performance testing (although
the aim would be for a headless system).
Available approx US$50 at
https://www.aliexpress.com/item/ESP-WROVER-KIT-ESP32-V3-Development-Board-with-WiFi-Wireless-Bluetooth-with-3-2-inch-LCD/32834370473.html
and https://www.adafruit.com/product/3384


>> I don't think there's any need for 16 bit; pretty much all IoT stuff is either
>> ARM (with quite a lot of it using v8 cores because you might as well) or
>> ESP/tensegrity. The ESP32 would run a stack vm ok I suspect, just needing
>> a well trimmed image. The tiny ARM machines could potentially even run a
>> Cog vm when memory allows.

> If you have a chip with 512KB of RAM, running a 16 bit image would get
> you roughly the same results as a 32 bit image in 1MB (actually less
> since Strings and Bitmaps would not change size).

True, but memory keeps getting bigger and cheaper on all devices.

cheers -ben


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