topic i.MX6SDL GPIO unexpected behavior. in i.MX Processors

i.MX6SDL GPIO unexpected behavior.

satoshishimoda — Fri, 13 Feb 2015 00:57:45 GMT

Hi community,

Our partner met a problem when I use a GPIO function of i.MX6.

Value of GPIO_DRI was cleared when I switched GPIO_GDIR.

Initialization flow was the following procedure.

① set value of GPIO_DR

② set value of GPIO_GDIR

But I set a port to 1 (high) and set GPIO_GDIR to 1 (output) of after that, then GPIO_DR value switched to 0 and it output low (our partner want to high signal).

As long as I read datasheet, I think that the above behavior doesn't occur.

Do you know the reason why the above behavior occurs?

Also, if I set value of GPIO_GDIR before I set value of GPIO_DR(29.4.2.2 GPIO Write Mode in i.MX 6Solo/6DualLite Applications Processor Reference Manual Rev.1, 04/2013), I think that a pulse exists for a moment.

In this case, Do you know how to prevent the pulse?

Best Regards,

Satoshi Shimoda

Re: i.MX6SDL GPIO unexpected behavior.

Yuri — Mon, 20 Apr 2015 08:10:51 GMT

Please try to enable GPIO module clocks before GPIO initialization.

//=============================================================================
// Enable all clocks (they are disabled by ROM code)
//=============================================================================

setmem /32 0x020c4068 = 0xffffffff

setmem /32 0x020c406c = 0xffffffff

setmem /32 0x020c4070 = 0xffffffff

setmem /32 0x020c4074 = 0xffffffff

setmem /32 0x020c4078 = 0xffffffff

setmem /32 0x020c407c = 0xffffffff

setmem /32 0x020c4080 = 0xffffffff

setmem /32 0x020c4084 = 0xffffffff

Have a great day,
Yuri

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Re: i.MX6SDL GPIO unexpected behavior.

satoshishimoda — Wed, 10 Jun 2015 05:04:27 GMT

Hi Yuri,

> setmem /32 0x020c4084 = 0xffffffff

There is no register on 0x020c4084.

Was this typo? Should we set 0xffffffff to 0x020c4088 (CCM_CMEOR register) instead of 0x020c4084?

Best Regards,

Satoshi Shimoda

Re: i.MX6SDL GPIO unexpected behavior.

Yuri — Thu, 11 Jun 2015 08:37:10 GMT

Yes, "setmem /32 0x020c4084 = 0xffffffff" should be removed.

Regards,

Yuri.