Re: PMC

[Mike Jones <proclivis@gmail.com>]

Patrick,

Now I see clearly.

I’ll see more where the ADI team wants to go in terms of demonstration.

Are there existing PMC implementations for ORv3, or is the work of your interest the first? Is their existing hardware to base OBMC running in a BMC to work from?

Mike

> On Apr 23, 2021, at 11:19 AM, Patrick Williams <patrick@stwcx.xyz> wrote:
> 
> Hi Mike,
> 
> On Fri, Apr 23, 2021 at 08:49:05AM -0600, Mike Jones wrote:
>> Patrick,
>> 
>> We are using spec: Open Rack V3 48V BBU.
> 
> Got it.
> 
> I think you'll want to look here:
> - https://www.opencompute.org/wiki/Open_Rack/SpecsAndDesigns
> 
>> In the case of a PMC, since I don’t know the OCP architecture well, is there a PMC device in the rack that would manage a BBU, or do devices that plug into their rack each have a PMC?
>> 
>> Looking at the above spec, the functions of the MCU are quite limited, so I assume there is a PMC device that is managing these other elements like a BBU. 
> 
> If you look at the Power Shelf design you'll see mention of a PMC/PMI
> connector.  This is a slot for which two different designs can fit into:
> PMC or PMI (and I don't recall exactly what the "I" stands for).
> 
> With PMC, the intended design was this was a full BMC-class device with
> a network interface.  This would run OpenBMC.
> 
> With PMI, there is a MCU in place of the BMC and the PMI is connected to
> the top-of-rack switch using a modbus / RS-485 over RJ-45 implementation
> like was available in ORv2.  I think the PMI would speak the same exact
> protocol as the similar device in ORv2.
> 
> You might find details on this modbus protocol in the above link, but
> there is a lot to dig through...
> 
> -- 
> Patrick Williams