[Tinyos-devel] More questions about using I2C on MicaZ / MTS300 (TinyOS 2)

[Vlado Handziski]

Hi Marina,
can you move this new thread to tinyos-help? We want to keep -devel only
focused on internal TinyOS development.

Thanks,
Vlado


On Thu, Jul 23, 2009 at 14:40, Marina Kurmanova
<marina.kurmanova at gmail.com>wrote:

> Hello again,
>
> I've been looking for schematic of the mts300 board in order to find out
> the model of its MIC sensor, but couldn't find anything. I want to know the
> I2C command set of the MIC, as well as its registers addresses. Where can I
> find it?
>
> Thanks in advance
> Marina
>
>
> 2009/7/21 Marina Kurmanova <marina.kurmanova at gmail.com>
>
> Thank you, very much. It was exactly that: the 7 bits of the slave address
>> of DS1621 are 1001000, or 0x48, but I treated them as 10010000, or 0x90,
>> using the 8th bit!!!
>>
>> Bye!
>>
>> 2009/7/21 Simon Kellner <kellner at ira.uka.de>
>>
>> * Marina Kurmanova [2009-07-21 14:59 +0200]:
>>> > Thank, you, Simon, the patch really solves the problem with the mts300
>>> > board.
>>>
>>> Glad to hear it.
>>>
>>>
>>> > Still, I cannot make I2C work with my DS1621 sensor. I wonder, how did
>>> you
>>> > get the new TOS_MIC_POT_ADDR = 0x2D address for mts300, and why did you
>>> > replace the old 0x5A address. Maybe it can help me with my DS1621
>>> sensor,
>>> > because I receive the EINVAL value on error parameter.
>>>
>>> Ok.  I2C devices can have 7-bit addresses, but the I2C controller
>>> transmits a full 8-bit byte including an address at the beginning of an
>>> I2C transaction.  The format on the wire is:
>>>
>>> 76543210
>>> AAAAAAAW
>>>
>>> That is, the bits of the address is transmitted first, and the last bit
>>> sets the mode of operation (read/write).  What I meant by 'real address'
>>> in the commit message was the content of bits 1 to 7 in the example.
>>> But the addresses in the TinyOS header file were multiplied by 2 so
>>> that the software just had to set bit 0 and then transmit it to the
>>> i2c controller.
>>>
>>> The current TinyOS implementation, however, shifts the address in
>>> the header file and then sets bit0.  So there is no need to store the
>>> shifted address.
>>>
>>> Bottom line:  Try dividing the address that is currently used by 2 and
>>> see if it works.  If not, you'll have to dig through the datasheet to
>>> find the right address of the device.
>>>
>>>
>>> > I would be glad to commit the patch to the TinyOS tree but I don't know
>>> how
>>> > to do it.
>>>
>>> This was addressed to TinyOS developers on the mailing list that has
>>> commit access.
>>>
>>>
>>> bye
>>>
>>
>>
>
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