EDE5104AGSE, EDE5108AGSE
Off-Chip Driver (OCD) Impedance Adjustment
DDR2 SDRAM supports driver calibration feature and the OCD Flow Chart is an example of sequence. Every
calibration mode command should be followed by “OCD calibration mode exit” before any other command being
issued. MRS should be set before entering OCD impedance adjustment and ODT (On Die Termination) should be
carefully controlled depending on system environment.
MRS should be set before entering OCD impedance adjustment and ODT should
be carefully controlled depending on system environment
Start
EMRS: OCD calibration mode exit
EMRS: Drive(1)
EMRS: Drive(0)
DQ & DQS high ; /DQS low
DQ & DQS low ; /DQS high
ALL OK
ALL OK
Test
Test
Need calibration
Need calibration
EMRS: OCD calibration mode exit
EMRS: OCD calibration mode exit
EMRS :
EMRS :
Enter Adjust Mode
Enter Adjust Mode
BL=4 code input to all DQs
Inc, Dec, or NOP
BL=4 code input to all DQs
Inc, Dec, or NOP
EMRS: OCD calibration mode exit
EMRS: OCD calibration mode exit
EMRS: OCD calibration mode exit
End
OCD Flow Chart
Preliminary Data Sheet E0715E20 (Ver. 2.0)
30
ELPIDA [ ELPIDA MEMORY ]
