GPMC and MMC1

Andreas Schlueter

Prodigy 90 points

Hi,

in TRM (26.1.7.5.2) :

* If MMC1 is used the GPMC interface is not usable, due to pin muxing options.

Could someone clarify, what "not usable" means ?

Pin Mux Utility (02_04_01_00) don't shows any conflict or violation

in our design (MMC1: IO Set Match, GPMC: IO Set Subset).

Andreas

over 13 years ago

0 BrandonAzbell over 13 years ago

TI__Guru 64770 points

This is because the AM335x ROM code only uses MMC1 on a particular set of pins when booting from that interface. This set of pins happens to also have the GPMC signals. This is described in Table 26-27 in Section 26.1.7.5.8 of the Technical Reference Manual.

0 Andreas Schlueter over 13 years ago in reply to BrandonAzbell

Prodigy 90 points

Hello Brandon,

thank you for advice.

If i understand you right, MMC1 and GPMC can be used simultaneously on runtime.

I.e. under Linux, is that correct ?

Andreas

0 BrandonAzbell over 13 years ago in reply to Andreas Schlueter

TI__Guru 64770 points

Andreas Schlueter said:

If i understand you right, MMC1 and GPMC can be used simultaneously on runtime.

Correct, provided you use the alternate pin muxing option for MMC1 that does not conflict with another function you need.

Andreas Schlueter said:

I.e. under Linux, is that correct ?

I realize there is a connection between the board support package within the Linux kernel and this functionality, so I don't want to dismiss this. However, at the moment, the task is to identify the hardware capabilities and then understand the software implication.

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GPMC and MMC1