topic USB OTG Functionality in i.MX Processors

USB OTG Functionality

sumit8915 — Mon, 20 Jul 2015 12:51:23 GMT

Hi All,

We are using a custom designed board having a standard USB host port (USB_H1) and USB OTG port terminated on a micro USB connector.

We are facing an issue in implementing the OTG Host mode when we are connecting the small micro usb cable convertor(USB micro-B to USB TYPE-A female connector). Even VBUS 5V also doesn't not comes up.

To verify the functionality of the USB_OTG_ID pin we have probed the pin and got fair results:

>> While connecting the small micro usb cable converter (USB micro-B to USB TYPE-A female connector) : USB_OTG_ID Pin -> 0

>> Normally during the Device mode functionality : USB_OTG_ID Pin -> 1 ( 3.23V as we have PU with 100K)

In SW side, We are doing following in DTS:

&usbotg {

vbus-supply = <&reg_usb_otg_vbus>;

pinctrl-names = "default";

pinctrl-0 = <&pinctrl_usbotg_1>;

disable-over-current;

dr_mode = "otg";

status = "okay";

};

[6:14:28 PM] Alok Pawar: reg_usb_otg_vbus: usb_otg_vbus {

compatible = "regulator-fixed";

regulator-name = "usb_otg_vbus";

regulator-min-microvolt = <5000000>;

regulator-max-microvolt = <5000000>;

gpio = <&gpio4 15 0>;

enable-active-high;

};

[6:14:48 PM] Alok Pawar: usbotg {

pinctrl_usbotg_1: usbotggrp-1 {

fsl,pins = <

MX6QDL_PAD_GPIO_1__USB_OTG_ID 0x17059

MX6QDL_PAD_KEY_COL4__USB_OTG_OC 0x1b0b0

MX6QDL_PAD_KEY_ROW4__GPIO4_IO15 0x0b0b0

};

Device Mode Functionality is working fine. But Host mode is not Working with this .

Thanks

Sumit

Re: USB OTG Functionality

igorpadykov — Tue, 21 Jul 2015 01:48:32 GMT

Hi Sumit

one needs to check why "VBUS 5V also doesn't not comes up",

please check how VBUS is produced on i.MX6_SABRE_SDP_DESIGNFILES

VBUS should be generated internally on board and provided on usb connector and

processor USB_OTG_VBUS.

Also one can test usb host mode with SDK test usb0_host_test.c

i.MX 6Series Platform SDK : Bare-metal SDK

Best regards

igor

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Re: USB OTG Functionality

sumit8915 — Tue, 21 Jul 2015 07:21:32 GMT

Hi Igor,

We have verified how VBUS is produced on i.MX6_SABRE_SDP_DESIGNFILES.

We are also generating the same way using a Current limit switch. Here is our design :

NOTE: Here USB_OTG_PWR is connected to the Micro USB connector and USB_OTG_VBUS is connected to the OTG VBUS Pin.

to verify the HW we are making USB_OTG_EN pin as 0(GPIO) and USB_OTG_PWR comes up as 5V.

But as per the OTG functionality USB_OTG_PWR should also comes up when we connect the small micro usb cable converter (USB micro-B (with ID pin GND) to USB TYPE-A female connector) so that we can connect a Peripheral device on the Type A connector of this cable.

Please let us know if we are missing anything to clarify.

Thanks

Sumit