3
33
► CAS Latency
The number of memory clocks it takes a DRAM to return data after the read CAS_L is asserted
depends on the memory clock frequency. The value that BIOS programs into the memory
controller is a function of the target clock frequency. The target clock frequency is determined
from the supported CAS latencies at given clock frequencies of each DIMM.
► tRCD (RAS-to-CAS Delay)
This item allows you to select a delay time (in clock cycles) between the CAS# and RAS#
strobe signals.
► tRP (Precharge Command Period)
This item allows you to select the row precharge time (in clock cycles).
► tRTP (Internal Read to Precharge Command Delay)
Internal READ Command to PRECHARGE Command delay.
► tRAS (Active-to-Precharge Delay)
This item allows you to set the minimum RAS# active time (in clock cycles).
► tRC (Active-to-Active/Auto-Refresh Command Period)
This item allows you to set the row cycle time (in clock cycles). tRC = tRAS + tRP.
► tWR (Write Recovery)
This item allows you to select the write recovery time (in clock cycles).
► tRRD (Active-to-Active of a Different Bank)
This item allows you to select a delay time (in clock cycles) between the RAS# and RAS#
strobe signals.
► TrwtTO (Read-to-Write Turnaround for Data. Optional only if CPU supports)
This timing parameter ensures read-to-write data-bus turnaround.
► Twrrd (Write to Read DIMM Termination Turn-around. Optional only if CPU supports)
This timing parameter accounts for termination timing when a write is followed by a read to a
different DIMM.
► tWTR (Internal Write to Read Command Delay)
This item allows you to select a delay time (in clock cycles) between sending the last data from
a write operation to the memory and issuing a read command.
► Twrwr (Write to Write Timing. Optional only if CPU supports)
This timing parameter accounts for turn-around timing when a write is followed by a write to a
different DIMM.
► Trdrd (Read to Read Timing. Optional only if CPU supports)
This timing parameter accounts for turn-around and termination timing when a read is followed
by a read to a different chip select.
► tRFC0, 1 (Auto-Refresh-to-Active/Auto-Refresh Command Period)
Refresh to Refresh or Refresh to Active command interval.
Trfc1: auto-refresh row cycle time for logical DIMM 1
Trfc0: auto-refresh row cycle time for logical DIMM 0
