512MB, 1GB, 2GB, 4GB (x64, DR) 240-Pin DDR2 UDIMM
Pin Descriptions
Table 8: Pin Descriptions (Continued)
Symbol
SDA
RDQSx,
RDQS#x
Type
I/O
Output
Description
Serial data:
Used to transfer addresses and data into and out of the SPD EEPROM on
the I
2
C bus.
Redundant data strobe (x8 devices only):
RDQS is enabled/disabled via the LOAD
MODE command to the extended mode register (EMR). When RDQS is enabled, RDQS
is output with read data only and is ignored during write data. When RDQS is disa-
bled, RDQS becomes data mask (see DMx). RDQS# is only used when RDQS is enabled
and differential data strobe mode is enabled.
Err_Out#
V
DD
/V
DDQ
V
DDSPD
V
REF
V
SS
NC
NF
NU
RFU
Output
Parity error output:
Parity error found on the command and address bus.
(open drain)
Supply
Supply
Supply
Supply
–
–
–
–
Power supply:
1.8V ±0.1V. The component V
DD
and V
DDQ
are connected to the mod-
ule V
DD
.
SPD EEPROM power supply:
1.7–3.6V.
Reference voltage:
V
DD
/2.
Ground.
No connect:
These pins are not connected on the module.
No function:
These pins are connected within the module, but provide no functionality.
Not used:
These pins are not used in specific module configurations/operations.
Reserved for future use.
PDF: 09005aef80f09084
htf16c64_128_256x64ay.pdf - Rev. G 3/10 EN
6
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2003 Micron Technology, Inc. All rights reserved.
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