topic Should SD1_CD_B be pulled low for Wi-Fi over SDIO (i.mx6ULL)? in i.MX Processors

Should SD1_CD_B be pulled low for Wi-Fi over SDIO (i.mx6ULL)?

abin444 — Wed, 06 Sep 2017 06:45:17 GMT

Hi,
We have a WiFi module always connected to i.MX6ULL processor over SDIO interface (4bit mode). My doubt is regarding SD1_CD_B pin. Is it necessary to have a pull down on this pin for SDIO to function? ( thought I could save a pin). In some designs (like Atmel) I could see DATA_3 pulled up for some purpose (DATA 3 also functions as card detect in that case).

i.MX6ULL says DATA_3 functions as a card detect in 1 bit mode.
Kindly clear clear the air.
Must I pull down SD1_CD_B or give pull ups on the data lines for a WiFi module to work over SDIO?

Will the SDIO interface work by tweaking software if SD1_CD_B is not used?

Thanks

Re: Should SD1_CD_B be pulled low for Wi-Fi over SDIO (i.mx6ULL)?

igorpadykov — Wed, 06 Sep 2017 07:13:00 GMT

Hi Abin

this is optional and depends on dts settings for usage usdhc

controller internal card detection, for available options please refer to

sect.32.3.3 Devicetree Binding attached Linux Manual.

Best regards
igor
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Re: Should SD1_CD_B be pulled low for Wi-Fi over SDIO (i.mx6ULL)?

abin444 — Mon, 11 Sep 2017 12:23:45 GMT

Thank you! That solves it :smileyhappy: