[coreboot] Embedded Controller (EC)

[Randall Spangler]

On Fri, Dec 8, 2017 at 5:57 AM, Аладышев Константин <aladyshev at nicevt.ru>
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.


> Best regards,
> Aladyshev Konstantin
>
>
>
> From: rspangler at google.com [mailto:rspangler at google.com] 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 <vbendeb at chromium.org>
> 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 <aladyshev at nicevt.ru>
> 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?
>
> 1) 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).
>
>
> 2) 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
>
> 3) 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
>
>
> --
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> https://mail.coreboot.org/mailman/listinfo/coreboot
>
>
>
>
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