GPMC with OSD335x C-SIP

[PD]

Is it possible to use GPMC with the C-SIP? I know the lower byte pins (AD0-AD7) are unavailable because it’s shared with the eMMC, but I can’t find anything explicitly documenting whether I could (for example) leave AD0-AD7 for eMMC and pinmux AD8-AD15 as GPMC and simply use the upper byte (even if reading the lower byte returns garbage that I mask in software).

Does having the eMMC pinmuxed on AD0-AD7 conflict with pinmuxing AD8-AD15 to GPMC? I’m looking to connect a FIFO-like expansion, so I’d just need several data bits, the GPMC clock, and maybe a couple control signals. Thanks.

[Neeraj Dantu]

PD,

The best way to utilize the GPMC interface would be to use the OSD335x-SM, which does not include the eMMC and therefore can provide access to all the pins of the GPMC interface. 

Using the C-SiP for this purpose would be unnecessary, as your use case disregards the eMMC completely.

Best,

Neeraj

[PD]

Thanks for the reply. To clarify my question, I’m wondering if I can retain eMMC functionality and still use a portion of the GPMC. If I leave eMMC as-is, and can pinmux only the circled pins (and maybe some control signals) in the attached image as GPMC pins, then I could still have an 8-bit wide high speed interface to an external device, even if I have to shift/mask my reads/writes, for example: byte_rx=(gpmc_in&0xFF00)>>8; or: gpmc_out=(byte_tx<<8); .

It’s not clear to me whether pinmuxing only a portion of the GPMC is a valid configuration, without conflicting with eMMC (other peripherals seem to allow it though). Thanks.

Attachments:

1. 

   gpmc.png
   

[Author]

Posts