|
|
# EEPROM 24C02 - But why?
|
|
|
|
|
|
## Update (January 2022)
|
|
|
|
|
|
The latest version of the standard, ANSI/VITA 57.4-2018 defines that both 24C02 and 24C32 devices may be used:
|
|
|
|
|
|
**Observation 5.4-1:** VITA 57.1 specifies the use of a 2Kb EEPROM per the IPMI specification
|
|
|
which calls up a **24C02**. <snip> The 2Kb EEPROM does not provide
|
|
|
enough space for all FMCs, and larger EEPROMs are desired. 2Kb and smaller EEPROMs use
|
|
|
one byte addressing. <snip> As a result, the decision was made to
|
|
|
skip over the 4 to 16Kb EEPROMs and specify a 32Kb or larger **24C32** compatible EEPROM if a
|
|
|
module needs a larger EEPROM. Since the 24C32 uses two byte addressing, it also has a
|
|
|
different base address than the 24C02 compatible EEPROMs.
|
|
|
|
|
|
**Observation 5.4-2:** For carrier cards to discern between 2Kb and 32Kb EEPROMs, they must
|
|
|
first look for the 2Kb EEPROM at the addresses provided in Table 5.4-1. If not found, look for the
|
|
|
32Kb EEPROM per Table 5.4-2.
|
|
|
|
|
|
See also [FPGA Mezzanine Card Plus (FMC+) standard AV57.4-2018](https://catalogue.library.cern/literature/n6rga-vgv34) - (CERN only)
|
|
|
|
|
|
|
|
|
## Original from May 2021
|
|
|
|
|
|
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
|
... | ... | @@ -181,3 +202,6 @@ On 2018-02-15 9:21 AM, Federico Vaga wrote: |
|
|
>
|
|
|
|
|
|
|
|
|
---
|
|
|
|
|
|
27 January 2022 |
|
|
\ No newline at end of file |