M34E04B Datasheet, PDF (20/35 Pages) STMicroelectronics – 4-Kbit Serial Presence Detect EEPROM compatible

Use within a DDR4 DRAM module
5
Use within a DDR4 DRAM module
M34E04B
5.1
5.1.1
In the application, the M34E04B is soldered directly in the printed circuit module. The three
slave address inputs (SA2, SA1, SA0) must be connected to V_SS or V_CC directly (that is
without using a serial resistor) through the DRAM module connector (see Table 3 and
Figure 3). The pull-up resistor on SDA is connected on the SMBus of the motherboard (as
shown in Figure 9).
DIMM position
0
1
2
3
4
5
6
7
Table 3. DRAM DIMM connections
SA2
SA1
V_SS
V_SS
V_SS
V_SS
V_CC
V_CC
V_CC
V_CC
V_SS
V_SS
V_CC
V_CC
V_SS
V_SS
V_CC
V_CC
SA0
V_SS
V_CC
V_SS
V_CC
V_SS
V_CC
V_SS
V_CC
Programming the M34E04B
The situations in which the M34E04B is programmed can be considered under two
headings:
• when the DDR4 DRAM is isolated (not inserted on the PCB motherboard)
• when the DDR4 DRAM is inserted on the PCB motherboard
Isolated DRAM module
With a specific programming equipment, it is possible to define the M34E04B content, using
Byte and Page write instructions, and the write-protection SWP(n) and CWP instructions. To
issue the SWP(n) and CWP instructions, the signal applied on SA0 must be driven to V_HV
during the whole instruction.
5.1.2
DRAM module inserted in the application motherboard
Table 4 and Table 5 show how the Ack bits can be used to identify the write-protection
status.
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