Lpc2000

Thanks Mark.  I think I'm on the right track.  I've gotten the 0x18
response from addressing my chip.  But, I had forgotten to set the AA
bit.  It wouldn't work until then and I kept getting 0x08.

Sutton


--- In lpc2000@yahoogroups.com, "Mark Butcher" <M_J_Butcher@...> wrote:
>
> Hi Sutton
> 
> 
> > In the 'C' code, it appears that all the manipulation is done
> > to the SDA and SCL lines directly.
> 
> The example is very probably a bit-banging example for any chip, 
> even without an IIC controller. Of course you can also bit bang on 
> any port which can be configured as input and output - therefore the 
> code will even run.
> 
> If you want to use the IIC controller in the LPC then it will only 
> give you some ideas - you can use polling mode [presumably as in the 
> bit-banging example] or interrupt driven with teh internal IIC 
> controller.
> 
> Here's how to send (defines are hopefully logical) and it is assumed 
> that the I/O lines are configured for IIC, rather than general 
> purpose ports - interrupts configured and enabled.
> 1.     I2CONSET = (I2EN + STA); - send start condition
> 2. On interrupt, read I2STAT, which will read as 0x08. Now send 
> I2DAT = Address_of_chip;     followed by      
> I2CONCLR = (SIC);               // clear the SI bit and continue
> 3. When the slave sends an ACK to its address, the interrupt routine 
> is called and I2STAT is 0x18.
> I2DAT = ucI2CTxData;     // send the first byte of data 
> I2CONCLR = (SIC + STAC);      // clear the SI bit and STA bit
> 
> 4. Subsequent interrupts have the status 0x28 and the next byte of 
> data can be sent using the previous sequence, until all data has 
> been sent, in which case the following code is used:
> I2CONCLR = (SIC + STAC);      // clear the SI bit and STA bit
> I2CONSET = STO;               // set stop bit  
> 
> The transmission has now completed.
> 
> There are however a number of details which I haven't described, as 
> well as the receive case. For example there can be a number of error 
> interrupts such as a slave not responding and when using multi-
> master it can get even more complicated.
> Also some devices (possibly yours(?)) need a sequence where they are 
> first addressed and then a re-start sequence is performed before the 
> actual data is sent.
> 
> Therefore it is best to read through the operation of the controller 
> and device, including the error conditions and get to know the 
> protocol in some more detail (if multi-master mode is not required 
> then just ignore its details since it is much easier then).
> 
> Perhaps this has also cleared up the SI use.
> 
> Cheers
> 
> Mark Butcher
> www.mjbc.ch
> 
> > 
> > Another ? I have is that in the user manual, it always says 'When 
> your
> > data has been sent and the acknowledgement has been received, then
> > ....', is the ACK the SI bit?  Or do I have do anything else 
> besides
> > clear the SI bit to 'get the acknowledgement'?  Not clear on 
> that...
> > 
> > Sutton
> > 
> > Sutton
> >
>