i.MX ProcessorsのトピックRe: i.MX6SX GPIO voltage select (USB_H_STROBE)

i.MX6SX GPIO voltage select (USB_H_STROBE)

kubiznak_petr — Mon, 02 May 2016 07:26:31 GMT

Hi all.

Looking in the Reference Manual of the i.MX 6SoloX processor, chapter 35 (IOMUXC), there are some pads which seem to have selectable output voltage. In particular, I'm speeking about the USB_H_STROBE pad. The DSE field of the IOMUXC_SW_PAD_CTL_PAD_USB_H_STROBE register allows to set the output resistor, where each value corresponds to three different resistors, conditioned by some "mode". E.g. the default value 110 corresponds to 43 Ohm @ 3.3V, 25 Ohm@1.8V, 40 Ohm for DDR.

My question is how to switch between the voltage "modes", i.e. how to switch the output voltage between 3.3V and 1.8V.

Re: i.MX6SX GPIO voltage select (USB_H_STROBE)

igorpadykov — Mon, 02 May 2016 12:46:14 GMT

Hi Petr

some iomux pad regsiters have LVE bit - Low Voltage Enable Field,

this pad has not such selection, so it is necessary just to set appropriate

NVCC_USB_H voltage according to Table 11. Operating ranges i.MX6SX Datasheet

http://cache.freescale.com/files/32bit/doc/data_sheet/IMX6SXCEC.pdf

Best regards

igor

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Re: i.MX6SX GPIO voltage select (USB_H_STROBE)

kubiznak_petr — Mon, 02 May 2016 13:51:00 GMT

Hi Igor,

Thanks for your reply. So I suppose the mentioned DSE field description is incorrect in case of the USB_H_xxx pads. But that does not really hurt me now.

Thank you, Petr