
440GX – Power PC 440GX Embedded Processor
80
AMCC
Revision 1.15 – August 30, 2007
Data Sheet
DDR SDRAM Write Operation
The following diagram illustrates the relationship among the signals involved with a DDR write operation.
DDR SDRAM Write Cycle Timing
DQS
MemData
PLB Clk
MemClkOut0
MemClkOut0(90)
Addr/Cmd
TSK
TSA
THA
TDS
TSD
THD
TSD
THD
TSA = Setup time for address and command signals to MemClkOut0(90)
TSK = Delay from rising edge of MemClkOut0(0) to rising/falling edge of signal (skew)
THA = Hold time for address and command signals from MemClkOut0(90)
TDS = Delay from rising/falling edge of clock to the rising/falling edge of DQS
TSD = Setup time for data signals (minimum time data is valid before rising/falling edge of DSQ)
THD = Hold time for data signals (minimum time data is valid after rising/falling edge of DSQ)