The ODT_WR_CFG parameter of the CSn_CONFIG register indicates that write latency plus additive latency must be at least 3 to use ODT. Our application uses an MPC8610 with 64-bit DDR2 w/ECC running at 200 MHz (DDR400). Nominal CAS Latency is 3 and write latency is 2. ODT is required. Can CAS latency of 3, write latency of 2, and additive latency of 1 be used to meet this requirement and utilize ODT? If so, should the RD_TO_PRE field of the TIMING_CFG_2 register include the additive latency (1 additional clock) or should it just include the t_RTP duration (2 clocks) when additive latency is used?
Yes, CAS latency of 3, write latency of 2, and additive latency of 1 is ok to utilize ODT correctly.
RD_TO_PRE should be equal to tRTP, ADD_LAT should not be added.