[Arm-netbook] simplest internet connection

[Luke Kenneth Casson Leighton]

---
crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68


On Sun, Jul 17, 2016 at 12:30 PM, Nick Hardiman
<nick at internetmachines.co.uk> wrote:


> So if I got this right, I can set up a card with network access in three ways - a minimal standalone setup, a full desktop setup, or a PCB for many cards. First two are linked to the current crowdsourcing campaign, third one is a future enhancement.

 correct.

> Here’s what I understand about the first two. This look right? Please excuse my rough ASCII connections diagrams

 we like ascii connections.  thank you for not doing them as HTML.

> a minimal standalone setup
>
> power socket
> |
> power plug, $6
> delivering at least 3 watts, so thats practically any USB charger
> https://www.amazon.com/AmazonBasics-Wall-Charger-Outlet-Output/dp/B005CG2ATQ/ref=sr_1_7
> |
> USB OTG cable, $1.63 (!)
> https://www.amazon.com/Micro-Cable-Power-Samsung-Player/dp/B00CXAC1ZW/
> or
> USB + HDMI Cable Set, $15
> https://www.crowdsupply.com/eoma68/micro-desktop
> |  |
> |  USB to Ethernet adapter
> |  This one seems to contain an ASIX chip (AX88178)
> |  $25
> |  http://plugable.com/products/usb2-e1000

 plugable... mmmm... you're better off buying from thinkpenguin.

> |  |
> |  Network cable, to the network, say $10
> |
> Libre Tea Computer Card, $65

 that's basically it.  you won't be able to see any of the boot logs,
early kernel messages or OS boot logs with this setup.

 if you were to get the cable set *and* then plug in the HDMI cable
*and* the bootloader and kernel were configured to display onto HDMI,
*then* you would be able to use just the above, because you could plug
in a keyboard instead of the USB-ETH adapter.

> a full desktop setup, for seeing boot loader and kernel messages

 boot loader and kernel messages go to where the boot loader and
kernel are configured to send them.  *early* messages can *only* go to
the serial port.  this isn't a PC, it's an embedded computer.  if
you're not familiar with this you should read up on it, on the
linux-sunxi wiki, and ask more questions when you need to.

 basically the boot proces goes:

 * BROM (boot rom) http://linux-sunxi.org/BROM
 * NAND or SD/MMC 16k "very early bootloader".  this is so small it
can only do serial debug output

 depending on the very early bootloader, some people use allwinner
boot0/boot1, other people use u-boot "SPL" early bootloader, you have
different choices.

 * after u-boot-spl you can go direct to u-boot and from there LCD or
HDMI or UART is initialised, you can get early u-boot messages on LCD
or UART
 * boot0/boot1 is a bit weird, it can do LCD / HDMI initialisation but
it's for tablets, you don't get log messages.  you can put in your own
u-boot, that's where you could get LCD/HDMI started

 from there you get to kernel, that's when you have "console=XXXX"
from u-boot and associated scripts (uEnv.txt), that says where the
kernel console output goes.


 i will have this all set up correctly so that you won't need to do it
or know all of it in advance, and there will be people (at least me)
who can guide you through modifying it for particular setups.  there's
also the linux-sunxi community.


> Libre Tea Computer Card
> $65
> https://www.crowdsupply.com/eoma68/micro-desktop
> |
> Micro Desktop Housing
> $55
> https://www.crowdsupply.com/eoma68/micro-desktop
> |  |  |
> |  |  Network cable, to the network, say $10
> |  |
> |  Keyboard, Video, Mouse, say $100
> |
> power plug (a USB charger?)

 no, a 7-21v PSU (i'll likely supply a 12v one) with a standard 5.5mm
pin-positive jack.  the PSU is part of the micro-desktop kit.

l.