Shabbir,
I am currently looking into this and will get back to you shortly.
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Hi,
In our customize design with AM3352, we have interfaced tmp102 temperature sensor on i2c bus 2 for measuring ambient temperature. We have set upper (Thigh) and lower (Tlow) threshold value. In interrupt mode, If ambient exceeds upper threshold (Thigh) value then it suppose to trigger the ALERT pin and It is working as expected. Now I want to clear this interrupt. I couldn't able to find any way to clear this interrupt. How do I clear this interrupt ?
Reset of tmp102 also works for me. But I couldn't even find the way to reset the device. Can anyone tell me how do I reset tmp102 ?
Thanks and Regards,
Shabbir Limdiwala
Moving this to the temperature sensors forum.
Shabbir,
I am currently looking into this and will get back to you shortly.
Best Regards,
Mayrim Verdejo
Applications Engineer
MHRS Sensing Products
Hello Shabbir,
Thanks for explaining the issue you are seeing in detail. When you use the ALERT in Interrupt mode all you will see is a pulse (low active pulse-default mode)when you go over the Thigh or under the Tlow. It looks like Figure 8 in Page 10 of the TMP102 datasheet. As far as clearing goes in Interrupt mode, there is no need to clear ALERT since its actually a pulse and it goes back to its default state immediately.
In case if your ALERT (configured to interrupt mode) is not returning back to its default state as shown in figure 10 please check to make sure you have the the pull-up resistor connection to V+.
Also, regarding the Software reset- its same as a General call reset explained in page 11 of data sheet. Please keep in mind that you will need to re-program the device configuration since it goes back to the default settings after the reset operation.
Best Regards,
Abhi
Hi Abhi,
Thanks for the reply. I have little confusion in your explanation. Let me explain you my scenario, I have configured POL=0 in interrupt mode, Whenever ambient temperature exceeds T(high), I don't want to take immediate action, i would rather wait for some time and check whether temperature is still exceeding T(high) then and only then i will take action. So if there is a case where temperature is returning back in between T(low) to T(high), ALERT pin will not trigger if temperature is again exceeding the T(high). Here I am attaching ALERT pin functional diagram
So because of this behavior, i want some way to clear the interrupt.
If there is no way to clear the interrupt and soft reset is resolving the issue then I am okay to re program the device configuration.
Thanks and Regards,
Shabbir Limdiwala
Hello Shabbir,
Thanks again for the detailed explanation of your requirements. I have a suggestion other than your General call/software reset option.
Put the device in Comparator mode (POL=0) then Set the Thigh and Tlow.Once the temperature exceeds Thigh, ALERT will go Low (active). Now using the host controller keep reading temperature from TMP102 to continuously monitor the current temperature. Once you think you are ready to take action, program the Tlow register to a value that is less than the current temperature value. By doing this you will be dynamically programming the Tlow limit on order to reset the ALERT back to default state (high).
I hope this helps.
Best Regards,
Abhi
Hi Abhi,
This seems a good solution. I'll try and let you know if i still face any problem. Thanks abhi
Shabbir Limdiwala
Hi Abhi,
Your last suggestion won't work. As per diagram attached in previous post, Whenever temperature exceeds T(high), ALERT pin becomes active low, It will again become active high whenever any register read operation occurs. So according to your suggestion whenever i set T(low) greater then current temperature value then ALERT pin becomes active low and i will get interrupt which is of no use.
For now as per datasheet of tmp102, it seems only soft reset will clear the interrupt in order to achieve my requirement.
I also want to know the use of general call address used to reset the tmp102.
Thanks and Regards,
Shabbir Limdiwala
Hello Shabbir,
Register read will only affect the ALERT when you configure the device in Interrupt mode but not in Comparator mode.
You missed the first sentence in my response wherein I asked you to use the device in "Comparator mode (POL=0)" - this is graphically explained in 2nd waveform of the figure that's referred earlier in this post. For more information on this please go through "THERMOSTAT MODE (TM)" section in the Page 8 of the data sheet.
If you have further questions on implementation you can email me at abhishekmuppiri@ti.com with your contact information and we can have a quick phone call to resolve your challenges.
Best Regards,
Abhi