AnsweredAssumed Answered

Use GPIO1_IO4 for Wifi moulde PIN (WL_REG_ON)

Question asked by Jim Huang on Jul 20, 2018
Latest reply on Jul 22, 2018 by igorpadykov

Hi NXP experts,


Currently, I have found an issue about using MX6UL_PAD_GPIO1_IO04_GPIO1_IO04 as WL_REG_ON for wifi module.
I have configured this PINs as GPIO in my DTS, but after checking with SCOPE, I saw two kinds different behavior when DC ON Boot done. If this signal is generated by iMX6UL, how could I disable it?

One is as below. After Wifi init done successfully. I would see much noise in this boot result.
I don't know the noise come from, but I think it comes from iMX6UL.  
Does GPIO1_IO04 has the default behavior in BSP FW which doesn't mention in IMX6UL_14x14_evk.dts?


The other case is GPIO1_IO4 would be set as 2.8V after Wifi init done and the level would keep 2.8V.
At this moment, I bring up the wifi interface, it would be pulled up to 3.3V and has a chance to up successfully.
However, if I disable this interface once, it would be brought up anymore.
For the Wifi module, it might make sense due the WL_REG_ON is not at reset Level (0).
But, I also don't know why GPIO1_IO4 would keep 2.8V as the low-level stage.



Another found is the wave-form of Wifi driver init, the red is not Wifi driver make it.