AM335x -- GPMC I/O Subset -- WPn & DIR

Rob Rodrigues

Mastermind 19780 points

Hi Team,

I have an application where I want to select signals gpmc_wpn and gpmc_dir at the same time. The pin-mux tool reports an I/O Set Violation because these two signals are superset of the defined subsets.

Is there a reason why WPn and DIR sets are mutually exclusive? Would the I/O set have to be changed during code execution to facilitate unlocking memory - writing to memory - locking memory type transactions?

Regards,

over 10 years ago

0 Biser Gatchev-XID over 10 years ago

TI__Guru**** 393215 points

Hi Rob,

Could you post the .dat file?

0 Rob Rodrigues over 10 years ago in reply to Biser Gatchev-XID

TI__Mastermind 19780 points

I have posted the .dat

All domains are 3.3V and package is ZCZ

4606.PinMuxDesignState_AM335x-Rev2.x-gpmc-io-set-violation.dat

0 Biser Gatchev-XID over 10 years ago in reply to Rob Rodrigues

TI__Guru**** 393215 points

Hi Rob,

It seems that your observation is correct. Can you tell me what is connected to the GPMC bus and why do you need the DIR signal?

0 Rob Rodrigues over 10 years ago in reply to Biser Gatchev-XID

TI__Mastermind 19780 points

Hey Biser,

The application is outside of the use case of the GPMC. It had to do with using synchronous memory with the AM335x. I know the GPMC doesn't support it, but I was just curious if there was a specific reason these two signals are exclusive in the I/O subsets.

Regards,

0 Biser Gatchev-XID over 10 years ago in reply to Rob Rodrigues

TI__Guru**** 393215 points

I can't see any reason, except that this combination was not timing closed. The pinmux tool wiki has some comments:

http://processors.wiki.ti.com/index.php/Pin_Mux_Utility_for_ARM_MPU_Processors#IO_Sets_Functionality_.28AM335x_device_only.29

http://processors.wiki.ti.com/index.php/Pin_Mux_Utility_for_ARM_MPU_Processors#IO_Set_Violation_Status

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AM335x -- GPMC I/O Subset -- WPn & DIR