[Vm-dev] Re: [squeak-dev] MQTT for Squeak?

Ben Coman btc at openinworld.com
Sun Oct 30 14:06:28 UTC 2016

On Sun, Oct 30, 2016 at 9:26 PM, Ben Coman <btc at openinworld.com> wrote:
> On Sun, Oct 30, 2016 at 6:37 AM, tim Rowledge <tim at rowledge.org> wrote:
>> And now I have my ESP8266 with DHT22 temp/humidity sensor publishing ok. Arduino c++ is really quite an amazingly unpleasant language. We need Smalltalk on these things!
> How small could we conceivably make the VM to fit on one of these...?
> https://www.arduino.cc/en/Products/Compare
> For example the Mega...
> MCU: 8-bit 16 MHz AVR
> EEPROM:  4kB
> RAM:         8kB
> FLASH:      256kB
> Current vm build product sizes...
> 4.1M   phcogspurlinuxht/lib/.../pharo
> 4.8M   sqcogspurlinuxht/lib/.../squeak
> 3.9M   sqstkspurlinuxht/lib/.../squeak
> 1.2M   sqstkspurlinuxhtminimal/lib/.../
> That last one built without any internal nor external plugins.
> What areas might be attacked to feasibly improve on that, to the point
> it can meet rising hardware specs?
> The 8 bit-ness is probably a killer though (??)
> Maybe it would be better to port the VM to the ESP32...
> MCU:  32-bit 240 Mhz Tensilica Xtensa LX6
> ROM:  448 KBytes for booting and core functions
> RAM:  520 KBytes
> FLASH: 4MB (per retail boards - 4 x 16 MBytes supported)
> https://www.sparkfun.com/products/13907
> https://www.adafruit.com/products/3269
> https://cdn-shop.adafruit.com/product-files/3269/esp32_datasheet_en_0.pdf
> Those specs look like they are getting close enough to consider possibility.
> How small might an extremely minimal image be that just toggles an LED?
> Hmmm.... I wonder where we might find someone both familiar with the
> MCU and positively inclined to Smalltalk?
> https://en.wikipedia.org/wiki/Tensilica
> Some general ESP32 info...
> http://hackaday.com/2016/10/04/how-to-get-started-with-the-esp32/
> http://hackaday.com/2016/09/15/esp32-hands-on-awesome-promise/
> http://esp32.net/

Also, a slightly lower spec'd alternative, but ARM based may be an
easier port.  How feasible are these specs?
MCU: 32-bit 180 MHz ARM Cortex-M4F core
SRAM: 256 KB
FLASH: 2048 KB
SDRAM: 8MB - but maybe uses up too many I/O pins to make a useful
Arduino competitor
  $30 including 2.4" 240 x 320 LCD
Why not an arduino?... http://embedded.fm/blog/2016/8/16/lets-get-board

cheers -ben

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