Browse Prior Art Database

Identical I2C Components Sharing a Unique I2C Address

IP.com Disclosure Number: IPCOM000123301D
Original Publication Date: 1998-Sep-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 59K

Publishing Venue

IBM

Related People

Benayoun, A: AUTHOR [+4]

Abstract

The problem to fix is how to access separately many identical I2C components (for example EEPROM's) located on a card decoded by a unique I2C address.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 58% of the total text.

Identical I2C Components Sharing a Unique I2C Address

   Problem description

   The problem to fix is how to access separately many
identical I2C components (for example EEPROM's) located on a card
decoded by a unique I2C address.

   State of the art The I2C address is made of two fields:
  o  The first field is dedicated to I2C component
     identifier.  This identifier is hardwired in the chip
  o  The second field is dedicated to the I2C address inside
     the machine.  This is usually the card slot location which
     is hardwired on the board

   Therefore it can be easily understood that it is not
possible to address identical I2C components on a card.

   Applications of the invention The problem occurs when the
design requires at least two identical I2C components on the card.
That is usually the case with the EEPROM housing the VPD's (Vital
Product Data) when the board is made of a mother card and a daugther
card, each of them having their own VPD's.

   Description of the invention

   Brief description of I2C bus The I2C bus is made of two
signals: a clock signal (SCL) and a bidirectional serial data signal
(SDA).  I2C addresses and data are carried onto the SDA signal
according to the I2C protocol.

   The I2C address is made of 7 bits: 4 bits are dedicated to
I2C components while the remaining 3 bits are allocated to the user
for the design at box level.  As an example, the 7 address bits for
the I2C 256x8 EEPROM (PCF8582) are 10...