Re: [coreboot] Embedded Controller (EC)

[Shawn N]

On Fri, Dec 8, 2017 at 8:30 AM, Randall Spangler  wrote:
> On Fri, Dec 8, 2017 at 5:57 AM, Аладышев Константин 
> wrote:
> > Thanks for your answer!
> >
> > I've looked more closely at Chromium Embedded Controller project and EC
> > chips it supports. To my surprise 'chromeec' even supports ordinary STM32
> > controllers without ACPI EC registers (am I right?).
>
> Yes, we've used it for everything from the main EC to a USB-PD controller to
> a charger.  STM32 isn't suitable as the main EC for x86-based Chromebooks,
> of course, due to lack of eSPI / LPC.
> > So I think is it very important to do schematics as it is in Chromebooks
> > to make use of this project.
> >
> > Is there any chance to find schematics for Chromebook boards, to get
> > reference design of implementing ECs with ‘chromeec’ project?
>
> I don't know.  But it supports several STM32 discovery boards, so you can
> tinker with it on ready-built hardware.

There are also schematics available for several misc. peripherals that
use stm32 + cros_ec, see twinkie for example:

https://www.chromium.org/chromium-os/twinkie

Unfortunately there are no schematics for actual Chromebook mainboards
publicly available. I looked into making some public, but there were
some overriding concerns.
> > Best regards,
> > Aladyshev Konstantin
> >
> > From: [e-mail] [mailto:[e-mail]] On Behalf Of
> > Randall Spangler
> > Sent: Friday, December 01, 2017 7:02 PM
> > To: Vadim Bendebury
> > Cc: Аладышев Константин; Coreboot; Shawn N
> > Subject: Re: [coreboot] Embedded Controller (EC)
> >
> > On Fri, Dec 1, 2017 at 6:32 AM, Vadim Bendebury 
> > wrote:
> > [+cc a couple of guys who might have some advice in this respect]
> >
> > On Fri, Dec 1, 2017 at 5:07 AM, Аладышев Константин 
> > wrote:
> > Hello! I'm trying to understand, what is the easiest way today to
> > integrate
> > EC to custom motherboard? What controller should I choose for new custom
> > motherboard?
> > First of all, are there any ECs on market that ship with embedded
> >
> > firmware, where all you need to do is just a little bit of register
> > configuration (like SuperIO)? Or is it always like you need to write all
> > firmware by yourself?
> >
> > Most EC vendors that sell dedicated ECs also sell their SDK and source
> > code, but it's not cheap.  So usually roll your own, hopefully based on an
> > open design.
> >
> > In that case what is the main difference between
> > ordinary microcontroller (for example STM32) and some controller marked by
> > vendor as EC?
> >
> > Interfaces.  EC will have:
> > • Keyboard scanner
> > • eSPI / LPC for connecting to x86 SoC
> > • More I2C ports
> > (and in the old days, PECI and PS/2 ports).
> > How stable and flexible are projects about open EC firmware? Is it
> >
> > possible to adapt these projects for my custom motherboard?
> >
> > I'm talking about:
> > Chromium Embedded Controller:
> >
> > http://www.chromium.org/chromium-os/ec-development
> >
> > This is used on all current Chromebooks, so it's full-featured and stable.
> > We do tend to branch old boards, so if your motherboard has an old chipset
> > on it you may need to look back in time to find support for it.
> > Origami-EC: https://git.code.paulk.fr/gitweb/?p=origami-ec.git;a=summary
> > What is the current status of EC support from coreboot point of view?
> >
> > https://review.coreboot.org/cgit/coreboot.git/tree/src/ec
> >
> > Best regards,
> > Aladyshev Konstantin