Detecting Dedicated Charger or Charging Downstream Port via DM_STATE register on RT1064

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Detecting Dedicated Charger or Charging Downstream Port via DM_STATE register on RT1064

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gabrielharrison
Contributor III

Hi,

We are implementing charger detection on an RT1064 using the details in "42.3.7 Charger detection" of the reference manual.

The final stage of the detection required DP to be pulled high and DM_STATE monitored.

I have had a look a the I.MX6 example on Linux and it looks like it may be doing it externally. See https://community.nxp.com/t5/i-MX-Processors/i-MX6-USB-host-detection/m-p/875191

Is there a register to pull DP high?

Thanks,

Gabriel

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gabrielharrison
Contributor III

Has anyone got a solution to this?

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Alexis_A
NXP TechSupport
NXP TechSupport

Hello @gabrielharrison,

You can control the pull-up using the following register:

USB_nUSBCMD[RS].

Best Regards,

Alexis Andalon

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Alexis_A
NXP TechSupport
NXP TechSupport

Hello @gabrielharrison,

The charger detector is compliant with the Battery Charging Specification (rev 1.2). According to this specification, I think the pull-up logic is on the side of the charger and the difference between DP/DM state will let the detector known which kind of charger is detected.

Let me know if this helps you.

Best Regards,

Alexis Andalon

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gabrielharrison
Contributor III

Hi Alexis,

Thank you for your reply. Unfortunately is hasn't answered the question. A pull-up needs to be applied to test if the DP and DM lines are connected in the charger.

What I'm trying to establish is if the 1064 module has a mechanism to apply the pull-up to do the test.

Does anyone know this?

Gabriel

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