|
|
|
# EEPROM 24C02 - But why?
|
|
|
|
|
|
|
|
The [Schematics Design Review checklist](https://ohwr.org/project/ed/wikis/schematics-checklist#fmc-mezzanine-cards) specifies:
|
|
|
|
|
|
|
|
"An FMC mezzanine should have a specific EEPROM (24C02, not a
|
|
|
|
24AA64T-I/MC, or a DS1624 temp sensor with EEPROM)."
|
|
|
|
|
|
|
|
But why?
|
|
|
|
|
|
|
|
The short answer is:
|
|
|
|
> Note that Rule 5.74 already refers to 'Platform Management FRU Information Storage Definition v1.0' in another context, but this document also says: 'Presently, the supported devices are SEEPROMs that use a `24C02`-compatible interface, and SEEPROMs that are compatible with the Dallas Semiconductor DS1624 Temperature Sensor/SEEPROM interface.'
|
|
|
|
> "
|
|
|
|
>
|
|
|
|
> So, looks like Platform Management FRU Information Storage Definition
|
|
|
|
> v1.0 calls up 24C02 indirectly. We are opening up VITA 57.1 for revision, we will add this as an item for inclusion.
|
|
|
|
|
|
|
|
The following mail exchange explains...
|
|
|
|
|
|
|
|
----
|
|
|
|
|
|
|
|
From: Erik Van Der Bij <Erik.van.der.Bij@cern.ch>
|
|
|
|
Date: Wed, 28 Feb 2018 at 17:46
|
|
|
|
Subject: RE: Re: FMC Discussion Forum - VITA 57.1 Rule 5.69: onboard EEPROM
|
|
|
|
To: be-dep-co-ht (All members of BE-CO-HT) <be-dep-co-ht@cern.ch>
|
|
|
|
|
|
|
|
|
|
|
|
Hi,
|
|
|
|
|
|
|
|
After the design review of the CTR mezzanine, I discussed with Federico who told that with the future software he will be able to handle both the old EEPROM (24AA64) and the suggested 24C02 EEPROM. Basically he will first read the contents as in the 24C02 format and if that doesn't show up some specific fields in the right place, he would read again, this time expecting to see a 24AA64.
|
|
|
|
|
|
|
|
Federico has not yet implemented this, this work likely can be done after the ADC work and Mock Turtle.
|
|
|
|
|
|
|
|
So from now on, new FMC designs we will design in the 24C02 EEPROM. I have added this in the design review checklist [1].
|
|
|
|
|
|
|
|
Best regards,
|
|
|
|
Erik
|
|
|
|
|
|
|
|
[1] https://www.ohwr.org/projects/ed/wiki/schematics-checklist
|
|
|
|
|
|
|
|
PS: Sundance/UK is always using the 24C02. At the same time they don't think they have had a customer of their FMC carriers and FMC modules actually making use of this EEPROM.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
-----Original Message-----
|
|
|
|
From: Federico Vaga
|
|
|
|
Sent: 20 February 2018 17:48
|
|
|
|
To: be-dep-co-ht (All members of BE-CO-HT) <be-dep-co-ht@cern.ch>
|
|
|
|
Subject: Fwd: Re: FMC Discussion Forum - VITA 57.1 Rule 5.69: onboard EEPROM
|
|
|
|
|
|
|
|
Hello,
|
|
|
|
|
|
|
|
I just received the answer from the VITA people about my question about the EEPROM type.
|
|
|
|
|
|
|
|
The quick answer is: our FMC mezzanine probably are not 100% compliant on this point because, indirectly, it was specified EEPROM 24C02 while we use bigger EEPROMs
|
|
|
|
|
|
|
|
|
|
|
|
Following the full discussion (I re-formatted the last email because of some weird character).
|
|
|
|
|
|
|
|
---------- Forwarded Message ----------
|
|
|
|
|
|
|
|
Subject: Re: FMC Discussion Forum - VITA 57.1 Rule 5.69: onboard EEPROM
|
|
|
|
Date: Tuesday, 20 February 2018, 16:49:33 CET
|
|
|
|
From: Jing Kwok (VITA) <jing.kwok@vita.com>
|
|
|
|
To: federico.vaga@cern.ch
|
|
|
|
CC: jerry@vita.com
|
|
|
|
|
|
|
|
Thank you for pinging back ...
|
|
|
|
|
|
|
|
Here is response form one member ...
|
|
|
|
|
|
|
|
"I totally agree that the current standard is missing this detail. I think it would be good to specify this in the new 57.1 revision.
|
|
|
|
Abaco/4DSP always used 24C02 devices on FMCs, but others might have been using other devices.
|
|
|
|
|
|
|
|
Note that Rule 5.74 already refers to 'Platform Management FRU Information Storage Definition v1.0' in another context, but this document also says: 'Presently, the supported devices are SEEPROMs that use a `24C02`-compatible interface, and SEEPROMs that are compatible with the Dallas Semiconductor DS1624 Temperature Sensor/SEEPROM interface.'
|
|
|
|
"
|
|
|
|
|
|
|
|
So, looks like Platform Management FRU Information Storage Definition
|
|
|
|
v1.0 calls up 24C02 indirectly. We are opening up VITA 57.1 for revision, we will add this as an item for inclusion.
|
|
|
|
|
|
|
|
Thanks for bringing this to our attention.
|
|
|
|
|
|
|
|
Regards
|
|
|
|
|
|
|
|
--
|
|
|
|
Jing Kwok
|
|
|
|
Technical Director, VITA
|
|
|
|
w.602-281-4497 jing.kwok@vita.com
|
|
|
|
website FAQ: http://www.vita.com/FAQ
|
|
|
|
|
|
|
|
On 2018-02-15 9:21 AM, Federico Vaga wrote:
|
|
|
|
> Hello,
|
|
|
|
>
|
|
|
|
> as promised I'm here to ping you on this topic: I2C EEPROM on FMC
|
|
|
|
> cards
|
|
|
|
>
|
|
|
|
> On Tuesday, 23 January 2018 20:42:15 CET Federico Vaga wrote:
|
|
|
|
>> Thank you very much!
|
|
|
|
>>
|
|
|
|
>> I will wait news from you (or I will ping you)
|
|
|
|
>>
|
|
|
|
>> On Tuesday, January 23, 2018 8:40:05 PM CET Jing Kwok (VITA) wrote:
|
|
|
|
>>> I do not know the answer to this ... I will send the question to the
|
|
|
|
>>> WG to see how they respond.
|
|
|
|
>>>
|
|
|
|
>>> I do know there were some discussion in this area but I am not
|
|
|
|
>>> familiar with the details ...
|
|
|
|
>>>
|
|
|
|
>>> I will pass on responses as I get them ... Stay tuned, feel free to
|
|
|
|
>>> ping me.
|
|
|
|
>>>
|
|
|
|
>>> Regards
|
|
|
|
>>>
|
|
|
|
>>> --
|
|
|
|
>>> Jing Kwok
|
|
|
|
>>> Technical Director, VITA
|
|
|
|
>>> w.602-281-4497 jing.kwok@vita.com
|
|
|
|
>>>
|
|
|
|
>>> website FAQ: http://www.vita.com/FAQ
|
|
|
|
>>>
|
|
|
|
>>> On 2018-01-23 9:31 AM, Federico Vaga wrote:
|
|
|
|
>>>> On Tuesday, 23 January 2018 14:44:25 CET Jing Kwok (VITA) wrote:
|
|
|
|
>>>>> Hi Federico,
|
|
|
|
>>>>>
|
|
|
|
>>>>> Please see below.
|
|
|
|
>>>>>
|
|
|
|
>>>>> --
|
|
|
|
>>>>> Jing Kwok
|
|
|
|
>>>>> Technical Director, VITA
|
|
|
|
>>>>> w.602-281-4497 jing.kwok@vita.com
|
|
|
|
>>>>>
|
|
|
|
>>>>> website FAQ: http://www.vita.com/FAQ
|
|
|
|
>>>>>
|
|
|
|
>>>>> On 2018-01-22 4:05 AM, Federico Vaga wrote:
|
|
|
|
>>>>>> Hello,
|
|
|
|
>>>>>>
|
|
|
|
>>>>>> I would like to have clarifications about the FMC standard (in
|
|
|
|
>>>>>> particular rule 5.60).
|
|
|
|
>>>>> jk> re Rule 5.60: The mezzanine module card shall only have one
|
|
|
|
>>>>> load on the TMS signal.
|
|
|
|
>>>>> What is your specific question?
|
|
|
|
>>>> Ok, I just realize that I got an old draft from the CERN
|
|
|
|
>>>> repository. Actually I meant:
|
|
|
|
>>>>
|
|
|
|
>>>>
|
|
|
|
>>>> Rule 5.69: The IO mezzanine module shall provide an onboard EEPROM,
|
|
|
|
>>>> which shall interface with the I2C bus signals.
|
|
|
|
>>>>
|
|
|
|
>>>>
|
|
|
|
>>>> In the standard I did not find any information about the kind of
|
|
|
|
>>>> EEPROM to use on the FMC module. It looks like that this choice is
|
|
|
|
>>>> open to the designers. Is it correct? Indeed I found mezzanines
|
|
|
|
>>>> with 2K EEPROM and others with 64K EEPROM.
|
|
|
|
>>>>
|
|
|
|
>>>> If my understand is correct, then I think the standard should
|
|
|
|
>>>> improve by specifying the kind of EEPROM to use.
|
|
|
|
>>>>
|
|
|
|
>>>> The information about an FMC module is specified in the FRU which
|
|
|
|
>>>> is contained in the EEPROM on the module itself. How do I access,
|
|
|
|
>>>> in a standardized way, this information? The way of accessing an
|
|
|
|
>>>> EEPROM changes according to the EEPROM type. For example, we have
|
|
|
|
>>>> small EEPROM with 1Byte address, bigger EEPROM with 2Byte address,
|
|
|
|
>>>> or other EEPROM that uses the I2C address as part of the internal
|
|
|
|
>>>> address. If I have to know in advance the FMC modules plugged, then
|
|
|
|
>>>> I do not really need the FRU information for some sort of
|
|
|
|
>>>> auto-discovery software.
|
|
|
|
>>>>
|
|
|
|
>>>> The IPMI specification is clearer on this point. For example at
|
|
|
|
>>>> chapter 38 it says: "System software needs to know the operation of
|
|
|
|
>>>> a 24C02-compatible SEEPROM interface to access these devices."
|
|
|
|
>>>>
|
|
|
|
>>>> Why this is not specified in VITA 57? The FRU information, of
|
|
|
|
>>>> course, fits perfectly into the 24C02 EEPROM (and compatible
|
|
|
|
>>>> devices).
|
|
|
|
>>>>
|
|
|
|
>>>> Is there something that I miss?
|
|
|
|
>>>>
|
|
|
|
>>>> thank you :)
|
|
|
|
>
|
|
|
|
>
|
|
|
|
>
|
|
|
|
|
|
|
|
|