Lpc2000

IOn that system I think only one of the I2C buses has pullups fitted - the other doesn't.   Just checking you're not using the "second" I2C bus on the proto expansion board?

Worth also double checking the bit ordering (LSB or MSB) of any device you're talking to... I've seen people have back-to-front commands apparently "work" - for a little while anyways...  :-)

-- Alex
  ----- Original Message ----- 
  From: Sutton Mehaffey 
  To: lpc2000@yahoogroups.com 
  Sent: Thursday, May 04, 2006 9:34 PM
  Subject: [lpc2000] Re: I2C question


  Yes.  I'm using the Embedded Artists 2148 Demo board, in which the
  schematic shows pullups.  I'm connecting a RAM chip via their
  accessory prototype board, which has direct connections to the I2C bus.

  Sutton


  --- In lpc2000@yahoogroups.com, "Dezheng Tang" <dtang@...> wrote:
  >
  > Do you have pull-ups on SCK and SDA lines?
  > 
  > 
  > --- In lpc2000@yahoogroups.com, "Sutton Mehaffey" <sutton@> wrote:
  > >
  > > Can someone unconfuse me on several I2C issues as I try to 
  > understand
  > > the Philips I2C code in the file section?
  > > 
  > > On, my design using a LPC2148, I am using Master Transmitter mode 
  > to
  > > address a RAM.
  > > 
  > > The AA flag: Is it only used to acknowledge data received from the 
  > RAM
  > > after reading from I2C0DAT?  I assume that the ACKs received from 
  > the
  > > RAM when simply addressing it is not related to AA (but is the SI
  > > bit).  I noticed in the Philips code that the only AA assertion is
  > > done after receiving data from the chip.  I also assume that the 
  > slave
  > > will always give an ACK after sending it data (by the SI flag).  
  > Or,
  > > am I totally off base?
  > > 
  > > Also, does SCL run all the time, or just during the data transfer? 
  > > I'm not seeing a SCL signal at all when I start my code.
  > > 
  > > Thanks.
  > > 
  > > Sutton
  > >
  >







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