This is the I2C spec for the chip I was fighting:
http://www.nxp.com/acrobat_download/usermanuals/UM10204_3.pdf
It has a (to me) useful description of the spec and clock/data sequence.
Careful comparison to your observations might turn something up.
Pay attention to the relationship between clock and data...IIRC the
data must be stable the entire time the clock is active (high or low,
I don't remember for sure...)
Are you sure you are sending the right slave address? If the target
doesn't agree it won't respond.
Is your TOS MSP I2C implemented in hardware or software?
MS
Tommaso Montisci wrote:
> Hi Michael, thanks for your answer.
>
> I try to explain you my problem:
> I'm able to send the START condition and the slave address, but I
> receive no ACK from my sensor(HMC6343 digital-compass). I know that I
> have sent the right-byte through the Oscilloscope.
> Without the acknowledgment it seems that I'm not able to sent further
> data to my device (is it true that I need the ack before sending data?).
>
> Have you any suggestions?
>
> best,
> Tommaso.
>
>
>
>
> 2009/8/23 Michael Schippling <[email protected] <mailto:[email protected]>>
>
> I discovered a "lapse of implementation" in the T1 atmega I2C
> implementation, which is BTW entirely done in bit-banging software.
> I don't use or have access to a T2 tree and haven't looked at the
> MSP implementation, but I might be able to help if you describe
> your problem.
>
> My problem was when reading multi-byte data from an I2C device.
> According to the spec the slave can request a "wait-state" between
> bytes. The TOS code was ignoring this and getting out of bit sync.
>
> MS
>
> Tommaso Montisci wrote:
>
> Hi all,
>
> I'm working to write TinyOS 2.x drivers for a 3-axiss digital
> compass(HMC6343).
> This sensor communicates via a two-wire I2C bus system as a
> slave divice with a microprocessor MSP430.
> I would like to know if someone just working in similar context
> couse I'm in trouble to recive the ack from the compass.
>
> Thanks,
>
> Tommaso Montisci.
>
>
>
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