HYB18H256321BF Datasheet, PDF (16/41 Pages) Qimonda AG – 256-Mbit GDDR3 Graphics RAM GDDR3 Graphics RAM

Internet Data Sheet
HYB18H256321BF
256-Mbit GDDR3
3.2
Extended Mode Register Set Command (EMRS1)
FIGURE 6
Extended Mode Register Set Command
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The Extended Mode Register is used to set the output driver
impedance value, the termination impedance value, the Write
Recovery time value for Write with Autoprecharge. It is used
as well to enable/disable the DLL, to issue the Vendor ID and
to enable/disable the Low Power mode. There is no default
value for the Extended Mode Register. Therefore it must be
written after power up to operate the GDDR3 Graphics RAM.
The Extended Mode Register can be programmed by
performing a normal Mode Register Set operation and setting
the BA0 bit to HIGH and BA1 bits to LOW. All other bits of the
EMR register are reserved and should be set to LOW.
The Extended Mode Register must be loaded when all banks
are idle and no burst are in progress. The controller must wait
the specified time t_MRD before initiating any subsequent
operation (Figure 9).
The timing of the EMRS command operation is equivalent to
the timing of the MRS command operation.
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Rev. 0.80, 2007-09
16
09132007-07EM-7OYI