MPC8308

[venkateshn]

Hi,

In MPC838 i have following clarifications,

1)  eTSEC IO Supply for RGMII will be 2.5V as per the datasheet but in reference design  LVDD1(NVDDF1) is connected to 2.5V and LVDD2(NVDDC1) is connected to 3.3V but i am thinking LVDD2 also needs to connect 2.5V so kindly clarify this.

2) for MPC8308 it is required to use VTT for DDR? in reference design they have not included this section and i am using only one device with 128MB density having organization 64MX16 so kindly clarify the VTT requirement.

[Bulat]

1) The MPC8308 is able to support RGMII with either 2.5V or 3.3V supply. You are right, normally RGMII works at 2.5V, however the PHY in the ref design requires 3.3V supply on the RGMII interface.  That is why eTSEC1 is powered with 3.3V to be on the same power rail with the PHY.

2) Yes, the ref design does not have VTT termination on the DDR interface. You can use this experience in your design, especially if you have point-to-point connections on the address/command/control signals.

Regards,

Bulat

[venkateshn]

Hi Bulat Karymov,

Thanks for your kind replay,

in MPC8308 i have interfaced 16 bit DDR2 SDRAM (IS46DR16160B from ISSI) to DDR controller and i left remaining 16 bit data bus open will it create any problem and i am attaching the Schematic for your reference kindly go through this and let me know any modfications.

2) for DDR2 SDRAM  is there any particular vendor recommendation from freescale now i am using  DDR2 SDRAM from ISSI having part number 
IS43/46DR16160B kindly check this part number.

3) can u suggest me the right part number for eSD chip or eMMC  with 16GB density which is compatible to MPC8308 .

4) can i connect 333MHZ or higher frequency SDRAM device to MPC8308 because it will support upto 266MHZ only.

Regards,

Venkatesh N