Just when I thought I had I2c sussed 24LC16WPI

Comments

• Archiver Posts: 46,084

  2002-10-09 02:44 edited 2002-10-09 02:44

  Try the data sheet at http://www.microchip.com/1010/index.htm
  Your assumption is correct, only one of these on a bus at a time. The
  address pins are no connects.
  
  Steve
  
  At 01:01 AM 10/9/02 +0000, you wrote:
  >I have this EEPROM hooked up and working fine, its not a
  >troubleshooting thing [noparse]:D[/noparse]
  >
  >Anyway, I thought I2C required that you set each chip's address by
  >grounding or pulling high the three address pins. THe 24LC16
  >doesn't! I've been searching the net for the last couple of hours
  >(including the yahoo group archive) and I can't seem to find
  >anything about this.
  >
  >If I stuck two of these chips onto the I2C bus, just how would I
  >differentiate between them? Or is it assumed that if you're cheap
  >arsed enough to buy just the 16k version then you won't have more
  >than one memory chip ? 8o\
  >
  >So far this is the only question I have about I2C. Got multiple SPI
  >chips working yesterday and today I'm trying I2C. In a month or so I
  >might actually start something useful.
  >
  >
  >
  >To UNSUBSCRIBE, just send mail to:
  > basicstamps-unsubscribe@yahoogroups.com
  >from the same email address that you subscribed. Text in the Subject and
  >Body of the message will be ignored.
  >
  >
  >Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
• Archiver Posts: 46,084

  2002-10-09 03:03 edited 2002-10-09 03:03

  As your luck would have it, the 24LC16 doesn't use the address pins, so you
  can only connect one device to your bus. You should probably download the
  specs (do a search [noparse][[/noparse]google] for 24LC16.PDF).
  
  The three "address" bits in the control byte actually select the one of eight
  256 byte blocks within the device. The address within the block is the next
  byte in the sequence.
  
  If you want to use multiple devices, consider the 24LC32.
  
  -- Jon Williams
  -- Parallax
  
  
  In a message dated 10/8/02 8:35:25 PM Central Daylight Time,
  ghidera2000@y... writes:
  
  
  > I have this EEPROM hooked up and working fine, its not a
  > troubleshooting thing [noparse]:D[/noparse]
  >
  > Anyway, I thought I2C required that you set each chip's address by
  > grounding or pulling high the three address pins. THe 24LC16
  > doesn't! I've been searching the net for the last couple of hours
  > (including the yahoo group archive) and I can't seem to find
  > anything about this.
  >
  > If I stuck two of these chips onto the I2C bus, just how would I
  > differentiate between them? Or is it assumed that if you're cheap
  > arsed enough to buy just the 16k version then you won't have more
  > than one memory chip ? 8o\
  >
  > So far this is the only question I have about I2C. Got multiple SPI
  > chips working yesterday and today I'm trying I2C. In a month or so I
  > might actually start something useful.
  >
  
  
  
  
  [noparse][[/noparse]Non-text portions of this message have been removed]
• Archiver Posts: 46,084

  2002-10-09 04:08 edited 2002-10-09 04:08

  Ah ok thanks for the replies!
  
  For once, I actually DID understand the data sheet then. I couldn't
  see how this chip could co-exist on the bus so I though I wasn't
  understanding the spec. I was wrong because I was right!
  
  Oh well, it'll still work fine for one of the projects I have in
  mind. Need it just for logging temperatures and storing strings for
  an LCD menu system.
  
  GLOAT: Got myself some 4x20 LCDs for $18 cdn apiece! Now I need more
  eeprom space to store strings [noparse]:D[/noparse]
• Archiver Posts: 46,084

  2002-10-09 09:38 edited 2002-10-09 09:38

  > GLOAT: Got myself some 4x20 LCDs for $18 cdn apiece! Now I need more
  > eeprom space to store strings [noparse]:D[/noparse]
  
  That's exactly what I'm doing with my datalogger project too. :-)
  
  Saved almost 20% stamp EEPROM by putting all display messages and Menu's in
  a 24C02 i2c eeprom (rather than, for example, startscreenmessage data
  "Hello", put the string "Hello" in to external memory...).
  
  
  Ben.
  
  
  --
  http://www.lennard.net.nz/
  Ben Lennard, NCEE, Dip EE
  
  Electronics R&D
  
  Hm: +64 4 972 7567
  Mb: +64 21 536 627
  87 Spencer Street
  Crofton Downs
  Wellington
  New Zealand
  
  "To the optimist, the glass is half full. To the pessimist, the glass is
  half empty. To the engineer, the glass is twice as big as it needs to be."
  
  No animals were harmed in the transmission of this email, although the
  Dog next door is living on borrowed time, let me tell you! Those of you
  with an overwhelming fear of the unknown will be gratified to learn that
  there is no hidden message revealed by reading this warning backwards.
  
  
  
  
  > From: "ghidera2000" <ghidera2000@y...>
  > Reply-To: basicstamps@yahoogroups.com
  > Date: Wed, 09 Oct 2002 03:08:26 -0000
  > To: basicstamps@yahoogroups.com
  > Subject: [noparse][[/noparse]basicstamps] Re: Just when I thought I had I2c sussed 24LC16WPI
  >
  > Ah ok thanks for the replies!
  >
  > For once, I actually DID understand the data sheet then. I couldn't
  > see how this chip could co-exist on the bus so I though I wasn't
  > understanding the spec. I was wrong because I was right!
  >
  > Oh well, it'll still work fine for one of the projects I have in
  > mind. Need it just for logging temperatures and storing strings for
  > an LCD menu system.
  >
  > GLOAT: Got myself some 4x20 LCDs for $18 cdn apiece! Now I need more
  > eeprom space to store strings [noparse]:D[/noparse]
  >
  >
  >
  > To UNSUBSCRIBE, just send mail to:
  > basicstamps-unsubscribe@yahoogroups.com
  > from the same email address that you subscribed. Text in the Subject and Body
  > of the message will be ignored.
  >
  >
  > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
  >
  >