AM335x temperature data from ADC

Alfred Yang

Dear sir,

I found a Temperature data from ADC (dtemp) in bandgap_ctrl Register (offset = 448h) in TRM, but cannot find any description about this filed.

Can this temperature data be used? And how to use it?

Thank you.

Regards,

Alfred Yang

over 12 years ago

0 Biser Gatchev-XID over 12 years ago

TI__Guru**** 393215 points

Hi Alfred,

This feature isn't supported at this time.

0 Alfred Yang over 12 years ago in reply to Biser Gatchev-XID

Prodigy 60 points

Dear Biser,

Thanks for your reply, will this function be implemented in the future?

By the way, I found similar register in AM37x TRM (section 13.4.6.2 Temperature Sensor), may I also know if the function in AM37x is usable?

Thank you.

Regards,

Alfred Yang

0 Biser Gatchev-XID over 12 years ago in reply to Alfred Yang

TI__Guru**** 393215 points

Hi Alfred,

I don't have information about future implementation. I think that this sensor is used by the AVS (Smart Reflex) firmware. About the AM37X, there is a separate forum (http://e2e.ti.com/support/dsp/sitara_arm174_microprocessors/f/416.aspx), but I think it's pretty much the same case.

0 Alfred Yang over 12 years ago in reply to Biser Gatchev-XID

Prodigy 60 points

Dear Biser,

I got it, thanks for your help!

Regards,

Alfred Yang

0 John Blair1 over 12 years ago in reply to Biser Gatchev-XID

Prodigy 30 points

Its 6 months later and I wanted to revive this question about the ADC temperature described as part of the bandgap_ctrl register on the AM335x.

When you write the feature "isn't supported" do you mean this feature not supported in the silicon or not supported in the linux BSP?

0 peaves over 12 years ago in reply to John Blair1

TI__Guru 62825 points

This is not supported because TI has no plans to provide a description for the use of this register since the operation of this register and the data it provides has not be characterized.

Regards,
Paul

0 Wim De Witte over 12 years ago in reply to peaves

Intellectual 300 points

Strange, because there's already an implementation:

https://github.com/beagleboard/kernel/commit/a14755efc9772405d4cd2cca78f607e6a85ffbaa

Thus this TI statement mean that the bandgap is not available in all silicon revisions?

I did not yet verify this driver.

Best Regards,

Wim

0 peaves over 12 years ago in reply to Wim De Witte

TI__Guru 62825 points

Several AM335x customers have wanted to monitor the junction temperature by reading a register.

I have discussed this topic with the product engineering team that characterized AM335x and was told the junction temperature was not characterized to any register value. Therefore, AM335x does not support any way to monitor the junction temperature by reading a register.

Regards,
Paul

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AM335x temperature data from ADC