Computer Old Farts Forum
 help / color / mirror / Atom feed
From: Ralph Corderoy <>
Subject: [COFF] Re: Porting the SysIII kernel: boot, config & device drivers
Date: Mon, 02 Jan 2023 09:37:18 +0000	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <20230101212609.yjg2poiggil7pwat@illithid>

Hi Branden,

> Paul Ruizendaal wrote:
> > That was my immediate pain point in doing the D1 SoC port.
> > Unfortunately, the manufacturer only released the DRAM init code as
> > compiler ‘-S’ output and the 1,400 page datasheet does not discuss
> > its registers. Maybe this is a-typical, as I heard in the above
> > keynote that NXP provides 8,000 page datasheets with their SoC’s.
> I don't think it's atypical.  I was pretty annoyed trying to use the
> data sheet to program a simple timer chip on the ODROID-C2
> OS nerds don't generally handle procurement themselves.  Instead,
> purchasing managers do, and those people don't have to face the pain.
> Data sheets are only as good as they need to be to move the product,
> which means they don't need to be good at all, since the people who
> pay for them look only at the advertised feature list and the price.

I think it comes down to the background of the chip designer.  I've
always found NXP very good: their documentation of a chip is extensive;
it doesn't rely on referring to external source code; and they're
responsive when I've found the occasional error, both confirming the
correction and committing to its future publication.

On the other hand, TI left a bad taste.  The documentation isn't good
and they rely on a forum to mop up all the problems but it's pot luck
which staffer answers and perennial problems can easily be found by a
forum search, never with a satisfactory answer.

My guess is Allwinner, maker of Paul's D1 SoC, has a language barrier
and a very fast-moving market to dissuade them from putting too much
effort into documentation.  Many simpler chips from China, e.g. a JPEG
encoder, come with a couple of pages listing features and some C written
by a chip designer or copied from a rival.

In my experience, chip selection is done by technical people, not
procurement.  It's too complex a task, even just choosing from those of
one supplier like NXP, as there is often a compromise to make which
affects the rest of the board design.  That's where FPGAs have an
allure, but unfortunately not in low-power designs.

Cheers, Ralph.

      parent reply	other threads:[~2023-01-02  9:38 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <>
     [not found] ` <>
     [not found]   ` <>
     [not found]     ` <>
     [not found]       ` <>
     [not found]         ` <>
     [not found]           ` <>
     [not found]             ` <>
     [not found]               ` <>
2023-01-01 17:21                 ` [COFF] Re: [TUHS] " Adam Thornton
2023-01-01 17:33                   ` Lars Brinkhoff
     [not found]       ` <>
     [not found]         ` <>
     [not found]           ` <20230101212609.yjg2poiggil7pwat@illithid>
2023-01-02  9:37             ` Ralph Corderoy [this message]

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).