AM1705 with USB OTG

David Brooks1

Other Parts Discussed in Thread: AM1707, AM1705

The Technical Reference Manual states that AM1705 supports USB OTG. However the DRVVBUS pin has been deleted (it was on the AM1707), obviously due to less pins on the AM1705 package.

So my question is: is USB OTG still possible on AM1705, & if so, are any specific pins recommended to use to sense & control VBUS (presumably with some external circuitry to handle the 5V level)? Do the standard software packages make any assumptions about this?

over 11 years ago

0 Biser Gatchev-XID over 11 years ago

TI__Guru**** 393215 points

Moving this to the AM1X forum.

0 Titusrathinaraj Stalin over 11 years ago

TI__Guru** 116100 points

Hi,

Yes, It does support USB OTG though DRVVBUS pin is not available, You have to drive/control VBUS pin through GPIO to enable USB host support.

0 Senthilkumar Srinivasan over 11 years ago

TI__Mastermind 43660 points

Hello David Brooks,

Yes, AM1705 supports OTG. You can implement this feature by using external USB power switch and controlling this switch through GPIO.

Please note, AM1705 device does not have VBUS pin also.

Regards,

Senthil

0 David Brooks1 over 11 years ago in reply to Senthilkumar Srinivasan

Prodigy 80 points

Many thanks. That's clear now :-)

0 Shankari G over 11 years ago

TI__Mastermind 43955 points

Hi David,

David Brooks said:
Do the standard software packages make any assumptions about this?

Yes, this should have been taken care in software, DaVinci-PSP-SDK-03.22.00.06. Find info at DaVinci-PSP-SDK-03.22.00.06/src/kernel/linux-davinci/drivers/usb/otg/gpio_vbus.c

Regards,

Shankari

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0 Senthilkumar Srinivasan over 11 years ago in reply to David Brooks1

TI__Mastermind 43660 points

Hello David Brooks,

The intention of posting this sample block diagram is to understand how to control the VBUS switch using GPIO when DRVVBUS pin is not available. Please not to take this as a reference design for your requirement.

And also this block diagram is not a TI recommended one.

Importantly, please ignore this posted sample schematics as it is not designed for AM1705.

Regards,

Senthil

0 Shankari G over 11 years ago in reply to Shankari G

TI__Mastermind 43955 points

Hi David,

With DaVinci-PSP-SDK-03.22.00.06, the OTG is ofcourse supported on both AM17xx and AM18xx.

We have verified this availability of OTG support on OMAPL137 SDI EVM ( ARM core same as AM17xx) and OMAPL38 SDI EVM (ARM core same as AM18xx).

Provided that the user has to enable the USB device driver (OTG ) support for both host controller and peripheral support while configuring the kernel)

Regards,

Shankari

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0 Senthilkumar Srinivasan over 11 years ago in reply to David Brooks1

TI__Mastermind 43660 points

The sample block diagram in above post is removed and edited.

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AM1705 with USB OTG