Lpc2000

Just learning to play with I2C.

I am trying to address a RAMTRON Serial RAM chip and am having some
difficulty getting proper responses from it.  I have the chip
addressed as 000, to make it easy on the electrical hookups.

My first trial is to READ data from a particular (selective) memory
location.

By reading, and if I understand it correctly, I need to do the following:

1. Issue a START command
2. Read the I2C0STAT register to determine the code.
3. An 0x08 means that START command was sent.
4. If 0x08 is received, issue a command thru I2C0DAT that contains the
chip select ID and the Device address.  Mine is 1010000x, where 'x' is
read (1) or write (0).  In this case A0.
5. Clear SI bit.
6. Read the I2C0STAT register to determine the code.
7. Should be either 0x18, 0x20, or 0x38 according to the manual.

Here's the result: 

After issuing a START command, I do get a 0x08 in the I2C0STAT
register (indicating START sent).  Then, I put the chip address in the
I2C0DAT register (0x40) which includes the Write bit in Bit 0.  I,
then, clear the SI bit.  But, I still get an 0x08 in the I2C0STAT
register.  I can never get anything else.  I tried clearing the SI bit
before putting the address on the bus, but still I get an 0x08.  Any
ideas what I am doing wrong in the sequence?  Thanks.

Sutton

Hello Sutton,

I think you need to clear the STA-bit after getting the 0x08 status.

Success,

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Aalt Lokhorst
Schut Geometrische Meettechniek bv
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E-mail: Lokhorst@...
==============================

> Here's the result:
> 
> After issuing a START command, I do get a 0x08 in the I2C0STAT
> register (indicating START sent).  Then, I put the chip address in the
> I2C0DAT register (0x40) which includes the Write bit in Bit 0.  I,
> then, clear the SI bit.  But, I still get an 0x08 in the I2C0STAT
> register.  I can never get anything else.  I tried clearing the SI bit
> before putting the address on the bus, but still I get an 0x08.  Any
> ideas what I am doing wrong in the sequence?  Thanks.
> 
> Sutton