Wat DDR2 frequencies r supported for CCB_CLK=400MHz

[ChandruK]

Hello,

Im using MPC8548E processor with SYSCLK as 100MHz, CCB CLKYSCLK = 4:1 and CORE:CCB CLK = 3:1. so the CCB_CLK will be 400 MHz.I have planned to use DDR2 memory, what DDR2 frequency will the system support? Will it be 400MHz/2 = 200MHz?

OR

Referring to the section 6.2.2 DDR SDRAM Output AC Timing Specifications of MPC8548E PowerQUICC™ III Integrated Processor Hardware Specifications the tMCK is 3.75ns does this mean that the processor will support a DDR2 with frequency 1/3.75ns = 266MHz??

Kindly help in this regard,

Thankingyou

Regards
Chandru

[IMX31]

Dear All, We are using MPC8548E (Rev 2.1) with on-board ddr2 of 512Mbytes. The DDR initialization hangs when the u-boot comes up. We see MSRCID [2] an input pin toggling. The u-boot version is 2010.03 and DDR hangs by showing *** failed *** *********************************************************************************************************************** U-Boot 2010.03 (Jun 22 2010 - 19:51:12) CPU: 8548E, Version: 2.1, (0x80390021) Core: E500, Version: 2.2, (0x80210022) Clock Configuration: CPU0:1000 MHz, CCB:400 MHz, DDR:200 MHz (400 MT/s data rate), LBC:25 MHz L1: D-cache 32 kB enabled I-cache 32 kB enabled Board: 8548 I2C: ready DRAM: DDR:cs0_bnds = 0x0000001f DDR:cs1_bnds = 0x00000000 DDR:cs2_bnds = 0x00000000 DDR:cs3_bnds = 0x00000000 DDR: cs0_cfg = 0x80044102 DDR: timing_cfg_0 = 0x00110105 DDR: timing_cfg_1 = 0x4c47a432 DDR: timing_cfg_2 = 0x331848ce DDR: timing_cfg_3 = 0x00010000 DDR: sdram_cfg = 0x83000008 DDR: sdram_cfg_2 = 0x04401000 DDR: sdram_mode = 0x439e0642 DDR: sdram_mode_2 = 0x8000c000 DDR: ssdram_md_cntl = 0x00000000 DDR: ssdram_interval = 0x04100100 DDR: ssdram_data_init = 0x00000000 DDR: ssdram_clk_cntl = 0x02800000 *** failed *** The exact size is not printed by the u-boot. What could be the problem? We went through the Register Configuration and also compared with register values of working board. Both match. Regards Raghu