unusual bare metal target: Amazon Dash

[Rikki Cattermole via Digitalmars-d-learn]

On 19/08/2015 3:24 a.m., Laeeth Isharc wrote:
> On Tuesday, 18 August 2015 at 04:36:49 UTC, Rikki Cattermole wrote:
>> On 18/08/2015 1:32 p.m., Laeeth Isharc wrote:
>>> I don't know whether D can run on one, but from a quick look perhaps
>>> feasible.  Running D on something like this (perhaps it's underpowered,
>>> but looked to have similar spec to what people had been doing with
>>> related ARM cortex processors) would certainly make the point very vivid
>>> that it can be a bare metal programming language.
>>>
>>> Only 1Mb of flash RAM for the program - is that enough?
>>>
>>> https://learn.adafruit.com/dash-hacking-bare-metal-stm32-programming/programming
>>>
>>>
>>> https://learn.adafruit.com/dash-hacking-bare-metal-stm32-programming/overview
>>>
>>>
>>>
>>> The Amazon Dash button is a tiny device that orders products from
>>> Amazon.com at the press of a button.  It's designed to be put wherever
>>> you store consumeables like paper towels, trash bags, etc. so that you
>>> can easily order more when they run out.  The Dash is great at what it's
>>> designed to do, but did you know inside the Dash is a powerful ARM
>>> Cortex-M3 processor and WiFi module that are very similar to wireless
>>> development boards like the Particle Photon?  You'll even find there are
>>> easily accessible test pads on the Dash which allow you to reprogram its
>>> CPU and turn it into your own $5 internet button!  This guide will
>>> explore how to take apart the Dash and reprogram its CPU to run your own
>>> code.
>>> ...
>>> The CPU is a STM32F205RG6 processor which is an ARM Cortex-M3 that can
>>> run up to 120mhz and has 128 kilobytes of RAM and 1 megabyte of flash
>>> memory for program storage.
>>> The WiFi module is a BCM943362 module which in combination with the CPU
>>> make it a platform for Broadcom's WICED SDK.
>>> There's a 16 megabit SPI flash ROM which is typically used in
>>> conjunction with the WICED SDK for storing application data.
>>> An ADMP441 microphone is connected to the CPU and used by the Dash iOS
>>> application to configure the device using the speaker on a phone/tablet.
>>> There's a single RGB LED and a button.
>>
>> By what you are saying, I believe it should be doable.
>> Although I'm a little worried for the WiFi support. Do you need to
>> include the code to drive it beyond wrap up some communication to it?
>>
>> 1mb flash should be enough to run D code on it. If you strip out a
>> good percentage of druntime and definitely no Phobos.
>> Although you may be able to mark and use some of that 16mb flash rom
>> as executable code storage. If that's so, you'll be in a good place to
>> have more then 1mb. It would require some clever runtime linking
>> tricks however.
>>
>> I'm probably not the best person to go more in depth about it or the
>> specific chips. So I won't. Most of my knowledge comes from reading
>> what others says and talking with Jens Bauer.
>
> I think its doable too.  Nobody seems to have figured out the wifi yet -
> more at LED flashing stage.   It's funny these wifi devices have
> microphones in them !

I was thinking about that. Maybe for speech recognition? Of course there 
is no way that device could actually analyze it.