K60 USB FS/LS OTG Controller: Few questions

[kaitav]

Hi everyone,

I am trying to implement USB OTG interface using Kinetis K60 microcontroller and have a few questions after doing some study. I am using the USB interface which has on-chip transceiver for OTG (chapter 48 in User Manual) and following questions are related to the same:

Q1. Is it must to use external IC (MAX3353E) for implementing OTG?

If so, what makes it necessary to have? I mean the microcontroller has configurable pull-ups and pull-downs, I can detect ID pin by connecting it to a GPIO and I can use external charge pump IC to support more devices on my TPL than what I can using MAX3353E. I was thinking that since OTG controller is built in with transceiver, I won't be required to interface such external IC and increase my burden by having to add even additional software in the form of I2C interface.

Q2. What are the values of internal pull ups and pull downs used in USB OTG interface? I am unable to find them in technical datasheet and user manual.

Edit: Ok, pull downs are 15Kohm - mentioned in user manual.

Q3. Does this OTG module support ADP protocol, VBUS discharging, data line pulsing, etc. required by the OTG standard? I can see that MAX3353E supports this but I can also see that the same is supported b the HS OTG controller in K60 (chapter 51 in user manual) but no such information is present in chapter 48.

I would really appreciate your answers.

Thank you,

Kaitav

Message was edited by: Kaitav Sapre: Edited Q2.

[garrettloverde]

Let's rephrase this question one more time.

How does the processor determine

     "when a change in VBUS is detected on an A device"

In order to set the AVBUSCHG flag in the USBx_OTGISTAT register

The description for this register says that it "Records changes of the ID sense and VBUS signals"

How are these signals monitored by the processor?

[egoodii]

It doesn't, there is no such monitoring by the processor.  The Kinetis instantiation of the USB peripheral block does NOT 'directly' support OTG.

[kaitav]

HI Hui,

Could you please give some advice on above queries?

Thanks,

Kaitav

[Hui_Ma]

Hi Kaitav,

Sorry for the so later reply.

I am checking with Kinetis product team about this thread, I will be back when I could get any updated info.

Thank you for the patience.

B.R.

Ma Hui

[kaitav]

Hi Hui,

No problems, I understand. Thank you for the reply. I will wait for your response.

Thanks,

Kaitav