CPLD interface for NAND to generate RD_B and CS_B in LS1046RDB schematic

[Nareshvarikuntla]

Dear NXP,

In LS1046A reference board, It is observed that NAND flash CS_B and RB_B are given from CPLD instead of directly giving from LS1046A.

So kindly let me know the reason.

Can I directly connect CS_B and RB_B signals of NAND flash from IFC nand interface. Does it have any limitations? Please let us know.

Will it impact QSPI interface?

[ufedor]

The LS1046ARDB CPLD implements direct connection of the signals:

//NAND Flash CS and RB assignment
assign nand_cs_b = ifc_cs0;
assign ifc_rb[1:0] = {1'b1, nand_rb_b};

This seems to be a leftover from the LS1043ARDB where NOR and NAND Flash devices are present and can be "swapped" to boot either from NOR or from NAND.

> Can I directly connect CS_B and RB_B signals of NAND flash from IFC nand interface.

Yes.