31.5.3.4 Power Supplies

The product embeds a dual power supply for the EBI: VDDNF for NAND Flash signals, and VDDIOM for other signals. This makes it possible to use a 1.8V or 3.3V NAND Flash independently of the SDRAM power supply.

The switch NFD0_ON_D16 is used to select the NAND Flash path on D0–D7 or D16–D23 depending on memory power supplies. This switch is located in the SFR_CCFG_EBICSA register (refer to 24 Special Function Registers (SFR)).

The following figure illustrates an example of the NAND Flash and the external RAM (DDR2 or LP-DDR or 16-bit LP-SDR) in the same power supply range (NFD0_ON_D16 = default).

Figure 31-2. NAND Flash and External RAM in Same Power Supply Range (NFD0_ON_D16 = default)

The following figure illustrates an example of the NAND Flash and the external RAM (DDR2 or LP-DDR or 16-bit LP-SDR) NOT in the same power supply range (NFD0_ON_D16 = 1).

This can be used if the SMC connects to the NAND Flash only. Using this function with another device on the SMC will lead to an unpredictable behavior of that device. In that case, the default value must be selected.

Figure 31-3. NAND Flash and External RAM Not in Same Power Supply Range (NFD0_ON_D16 = 1)

At reset NFD0_ON_D16 = 0 and the NAND Flash bus is connected to D[7:0].