AM2432: Is AM2432 NAND Flash NC on PCBA OK?

Jiaying Wu

Part Number: AM2432

Hi,

We have a question related to GPMC module in AM2432 MPU.

Currently our connecting structure is like below. NAND will share 8 databits with BOOTMODE0~7, and they are isolated by a buffer trigged by PORZ_OUT.

Now NAND is not needed in the system, but we cannot ensure if more requirements will be added and if we will need NAND in the future.

Is there any risk if we leave NAND’s pads and related traces on the PCBA but not assemble it?

We have checked AM24 datasheet 6.4 Pin Connectivity Requirements and do not find extra requirements except bootmode. As the output of the buffer is 'Z' when it is not triggered, we are a little worried that if the floating traces would act as antenna during normal operation or EMC test. If we don't initial GPMC module, can we eliminate the potential disturbance from the traces?

5 months ago

0 Anastas Yordanov 5 months ago

TI__Genius 9650 points

Hello Jiaying Wu,

Please look into this FAQ which suggests a buffered solution combined with usage of 0R resistors to allow alternate functions on the BOOTMODE pins (i.e. adding the NAND flash later):

Bootmode with isolation buffers and 0R resistors for alternate functions

Here is another FAQ that give recipes how to mitigate the noise induced by floating traces:AM64x / AM243x Design Recommendations / Custom board hardware design - Data sheet Pin Attributes and Pin connectivity related queries

The below FAQ provides a good explanation why shall be SoC pins to which signal traces are connected terminated with external pull resistors:

design recommendations and commonly observed errors during custom board hardware design soc peripherals and I/Os connection when not used

For more information on the GPMC0_AD0 - GPMC0_AD7 pin connections in case of added traces refer to the Section, General-Purpose Memory Controller (GPMC) / Subsection, Signals Connection of the AM243x Schematic Design Guidelines and Schematic Review Checklist.pdf

Thanks

Kind Regards,

Anastas Yordanov

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AM2432: Is AM2432 NAND Flash NC on PCBA OK?