[Arm-netbook] EOMA68 Power Specifications

[Luke Kenneth Casson Leighton]

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


On Wed, Aug 31, 2016 at 12:28 AM, Joseph Honold <mozzwald at gmail.com> wrote:
>
> On 08/30/2016 05:11 PM, Luke Kenneth Casson Leighton wrote:
>
>>> Seems like there should be a minimum power requirement that all cpu cards and devices must meet.
>>
>>  okay - so you used the word "devices" which is not part of EOMA68
>> terminology.  sorry i missed this, so didn't understand the question.
>
> I spose motherboard is the correct term i should have used.

 "Housing" is now the official term.  motherboard usually means "CPU
is on.... the motherboard".

>>  *from the perspective of the EOMA68 Cards* the *MAXIMUM* that they
>> are permitted to use is 1.0A @ 5.0v
>>
>>  therefore...
>>
>>  *from the perspective of EOMA68 ***HOUSINGS*** .... * the *MINIMUM*
>> that they must provide is: 1.0A @ 5.0v
>
> Maybe I'm misreading the spec, but I don't see it specify that my motherboard must be able provide 5V 1A to the cpu card. That's the reason for asking this question.

 i know... and it's a good question, which is why i've started a
section on the discussion page.

>>  above exactly 1.0A @ 5.0v, housings are ***REQUIRED*** to cut power
>> without warning.
>
> I don't see this in the spec either. Am I correct that http://elinux.org/Embedded_Open_Modular_Architecture/EOMA-68 is the 'official' specification for eoma-68?

 yes.  so it needs to be on that.

>>> This seems like a broken spec to me. Nothing in electronics is exact, so a
>>> sane spec should have a reasonable margin between the maximum current a card
>>> is allowed to draw and the point at which overcurrent protection is required
>>> to kick in.
>
>> appreciated - very good point  this is the first time it's really
>> been discussed.  i'm already uncomfortable with the idea of having 5.0
>> watts in an enclosed space.  3.5 is okay.  i _was_ thinking of raising
>> the Housing limit to 5.5 watts, but was slightly concerned that people
>> would abuse the extra headroom.
>>
>>  suggestions appreciated.... hmm... let me just add a section on the
>> specification / discussion on the elinux.org talk page to reference
>> this discussion...
>
> Adding a section for power specifics would help clarify things.

  yeahyeah.

l.