[Arm-netbook] Your personal wish list for an I/O board. (Was: EOMA-68 Carrier Board Concept)

[Scott Sullivan]

On 08/15/2013 11:43 AM, Philip Hands wrote:
> Scott Sullivan <scott at ss.org> writes:
>
> ...
>> Additionally, the question comes to my mind, how do you coordinate power
>> down of the IO board. I'm guessing there needs to be some sort of the
>> I2C power management chip for the I/O board? Otherwise how do you force
>> a power down of the USB peripherals? Phantom power issues if you don't
>> manage it?
>
> While considering power:  How about allowing for redundant supplies?  It
> would be cool to be able to detect one of the multiple power sources
> going away so that it would be possible for the machine to ask for
> maintenance in some way.
>
> Cheers, Phil.

While I love this idea, it think it's more suitable and cost effective 
in a multi-card chassis (rack mount?). Would certainly not be cost 
competitive for the single card I/O Board that Chris is outlining here.

Now, in the case of the EOMA-68-A20 Card I think you can achieve 
something similar. Luke has mentioned that I2C enumeration would be 
assumed from application of 5V to the EOMA-68 Interface. From this I 
infer that there is a way to distinguish between power from the USB OTG 
and the EOMA-68. If you can indeed detect this in software, and can 
safely power the card from both sides, I would reason that a cost 
effective method of achieving your goal. Although the first potential 
gotcha is if the I/O board needs to be powered for the Ethernet Jack to 
work correctly. (I haven't read the data sheets and only know some 
minimal electronics).


Now changing the Topic to reflect a more general Tangent.

What is your personal wish list for an I/O board. I know we have a fair 
survey already documented here: http://rhombus-tech.net/community_ideas/

I know for personal use I'd trying building a serial console server. I'd 
likely derive it from an arduino shield a colleague of mine did.

http://www.strichlabs.com/products/multiserial-shield
http://www.nxp.com/products/interface_and_connectivity/bridges/i2c_spi_slave_to_uart_irda_gpio_bridges/series/SC16IS752_SC16IS762.html

This chipset does has an existing SPI driver in the linux kernel. The 
heavy lifting would porting to I2C. Currently above me experience level, 
which makes is nice growth project.

-- 
Scott Sullivan