HYB18T512160AC-37 INFINEON [Infineon Technologies AG], HYB18T512160AC-37 Datasheet - Page 29

• Manufacturer Part Number: HYB18T512160AC-37
• Description: 512-Mbit Double-Data-Rate-Two SDRAM
• Manufacturer: INFINEON [Infineon Technologies AG]

Extended Mode Register Set for OCD impedance adjustment
OCD impedance adjustment can be done using the
following EMRS(1) mode. In drive mode all outputs are
driven out by DDR2 SDRAM and drive of RDQS is
dependent on EMRS(1) bit enabling RDQS operation.
In Drive(1) mode, all DQ, DQS (and RDQS) signals are
driven high and all DQS (and RDQS) signals are driven
low. In Drive(0) mode, all DQ, DQS (and RDQS) signals
are driven low and all DQS (and RDQS) signals are
driven high. In adjust mode, BL = 4 of operation code
data must be used. In case of OCD calibration default,
output driver characteristics have a nominal impedance
value of 18 Ohms during nominal temperature and
Table 9
A9
0
0
0
1
1
OCD impedance adjust
To adjust output driver impedance, controllers must
issue the ADJUST EMRS(1) command along with a 4
bit burst code to DDR2 SDRAM as in
operation, Burst Length has to be set to BL = 4 via MRS
command before activating OCD and controllers must
drive the burst code to all DQs at the same time. DT0 in
Table 10
1, and so forth. The driver output impedance is
adjusted for all DDR2 SDRAM DQs simultaneously and
Table 10
4 bit burst code inputs to all DQs
D
0
0
0
0
1
0
0
1
1
Other Combinations
Data Sheet
T0
means all DQ bits at bit time 0, DT1 at bit time
D
0
0
0
1
0
1
1
0
0
A8
0
0
1
0
1
T1
Output driver characteristics for OCD calibration
Off- Chip-Driver Adjust Program
D
0
0
1
0
0
0
1
0
1
A7
0
1
0
0
1
T2
D
0
1
0
0
0
1
0
1
0
T3
Operation
OCD calibration mode exit
Drive(1) DQ, DQS, (RDQS) high and DQS (RDQS) low
Drive(0) DQ, DQS, (RDQS) low and DQS (RDQS) high
Adjust mode
OCD calibration default
Table
Operation
Pull-up driver strength
NOP (no operation)
Increase by 1 step
Decrease by 1 step
NOP
NOP
Increase by 1 step
Decrease by 1 step
Increase by 1 step
Decrease by 1 step
10. For this
29
voltage conditions. Output driver characteristics for
OCD calibration default are specified in
applies only to normal full strength output drive setting
defined by EMRS(1) and if half strength is set, OCD
default output driver characteristics are not applicable.
When OCD calibration adjust mode is used, OCD
default output driver characteristics are not applicable.
After OCD calibration is completed or driver strength is
set to default, subsequent EMRS(1) commands not
intended to adjust OCD characteristics must specify
A[9:7] as ’000’ in order to maintain the default or
calibrated value.
after OCD calibration, all DQs of a given DDR2 SDRAM
will be adjusted to the same driver strength setting. The
maximum step count for adjustment is 16 and when the
limit is reached, further increment or decrement code
has no effect. The default setting may be any step
within the maximum step count range. When Adjust
mode command is issued, AL from previously set value
must be applied.
512-Mbit Double-Data-Rate-Two SDRAM
HYB18T512[400/800/160]A[C/F]–[3.7/5]
Reserved
Pull-down driver strength
NOP (no operation)
NOP
NOP
Increase by 1 step
Decrease by 1 step
Increase by 1 step
Increase by 1 step
Decrease by 1 step
Decrease by 1 step
Functional Description
09112003-SDM9-IQ3P
Rev. 1.13, 2004-05
Table
10. OCD