TMS320F28069: USB D+/D- pull-down register for host

Kzk

Hello,

Please tell me about USB D+/D- pull-down register. I can't see TRM(SPRUH18F) description of pull-down register as host even though I can see pull-up register as device. Since it complies with the USB specification, I think F28069 USB has built-in pull-down register for host on D+/D-. However, I can't see the low level on D+/D- when USB device is not conneted on our target board. Could you give me some advice?

Regards,
Kazu

over 9 years ago

0 Gautam Iyer over 9 years ago

Guru 192875 points

Hi,

Do check this post: e2e.ti.com/.../1019135

Regards,
Gautam

0 Kzk over 9 years ago in reply to Gautam Iyer

Genius 5785 points

Hello Gautam,

Thank you for your reply. But the post looks like a description about USB Device. According to USB specification, Host needs to pull down D+/D- by 15 kΩ register. Generally I think it achieves by internal pull-down register in USB Host. Does F28069 USB D+/D- have built-in pull-down resistor?

Regards,
Kazu

0 Kzk over 9 years ago in reply to Kzk

Genius 5785 points

Hello,

Could you send me a reply? Please help me.

Regards,
Kazu

0 Adam Haun over 9 years ago in reply to Kzk

TI__Expert 8950 points

Kazu,

The USB module has its own pull-ups and pull-downs in the built-in PHY. You don't need to use the chip-level GPIO pull-ups for USB.

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TMS320F28069: USB D+/D- pull-down register for host