[lm-sensors] TI TMP421 chip address

Andre Prendel andre.prendel at gmx.de
Wed May 27 13:44:36 CEST 2009


On Wed, May 27, 2009 at 01:08:19PM +0200, Hans de Goede wrote:
>
>
> On 05/27/2009 11:15 AM, Andre Prendel wrote:
>> Hi Hans,
>>
>> looking in the datasheet of the TMP421 sensor chip
>>
>> http://focus.ti.com/docs/prod/folders/print/tmp421.html,
>>
>> I saw the following addresses.
>>
>> TMP421  100 11xx
>> TMP422  100 11xx
>> TMP423A 100 1100
>> TMP423B 100 1101
>>
>> But the preliminary driver of your students uses 0x2a.
>>
>>   /* Addresses to scan */
>>   static unsigned short normal_i2c[] = { 0x2a, I2C_CLIENT_END };
>>
>> 0x2a == 010 1010b, right?
>>
>
> Right.
>
>> Do I misunderstand something?
>
> No, what my students did in there was wrong, they only put the
> address in there to which the sample I gave them is wired
>
> The addresses to scan should be:
> static unsigned short normal_i2c[] = { 0x1c, 0x1d, 0x1e, 0x1f,
>   0x2a, 0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
>
> But we better run those past Jean, to see if any of
> those are dangerous to scan by default, Jean ?
>
>> And what means the xx in the address of TMP421/422?
>
> This means that the address is configurable by hooking up
> the IC in different ways, see table 9 and 10 at page 17 of
> the data sheet.

Thanks, I didn't see this so far. Now I understand :)

>
> Regards,
>
> Hans

Andre




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