Official repo on GitHub:
https://github.com/1a2m3/SPD-Reader-Writer
 
Latest binaries:
https://github.com/1a2m3/SPD-Reader-Writer/releases
 
Latest firmware: (both *.ino and *.h files are required!)
https://github.com/1a2m3/SPD-Reader-Writer/tree/master/firmware
 

Guide:

Part 1 - hardware

 
Wire up your Arduino + DIMM/EEPROM according to the schematic below:
 

Click image to see full version. PDF and Eagle files can be found here
 
The schematic shows modules divided into sections:

• Arduino section shows pins used on Nano V3 model. Use its 3.3V pin as a VCC source. If your Arduino doesn't have a dedicated 3.3V output, use a step-down 3.3V regulator, like LM7833. Pins labeled SA0SW, SA1SW, SA2SW, HVSW, and HVDET can be assigned in "SpdReaderWriterSettings.h" file. 5V pin is required to power a 9V step-up converter (HV_SOURCE). If you are using a battery as a 9V source (HV_SOURCE_ALT), 5V pin on Arduino isn't used.
• HV_CTL and one of 9V sources are needed to enable and detect 9V on SA0 for RSWP related operations. Use either a step-up/boost converter (HV_SOURCE), or a 9V battery (HV_SOURCE_ALT), not both!
• SA1_CTL is used to switch pin SA1 on EEPROM between VCC and ground. This is needed because RSWP-supported EEPROMs used on DDR3 and DDR2 require different SA1 configurations to enable or disable RSWP.
• SA0_CTL_OPT and SA2_CTL_OPT work in the same manner as SA1_CTL, allowing switching SA0 and SA2 between VCC and ground, however no official specifications currently require SA0 and SA2 to be configured in specific ways, therfore these modules are optional.

 
Refer to your Arduino model pinout, on my Nano model SDA and SCL are A4 and A5, respectively: https://www.arduino.cc/en/reference/wire

 
Parts list:

• Arduino: Nano V3 or any model with I2C / TWI interface.
  
• OK1: PC817 or any optocoupler with a maximum collector to emitter voltage above 10V and a diode current below 40mA and forward voltage below 5V.
• OK2-OK4: Same as OK1, or any model with a maximum collector to emitter voltage above 3.3V. Diode requirements match OK1 specs.
  
• R1, R4, R5, R6: Current limiting resistors for optocoupler diodes, values between 390Ω and 560Ω work fine.
  
• R2, R3: Voltage divider for HV detection (HVDET) on SA0. If you are using a 5V Arduino, both can be 10KΩ. If you are using a 3.3V Arduino, R3 has to be 5.6KΩ.
• C1: 6.3V, 560uF
• D1: Any diode with a forward voltage drop of between 0.2V and 0.4V and reverse breakdown voltage of above 6V.

 
EEPROM pins to DIMM pins guide:
 
DDR4:    SA0=139,   SA1=140,   SA2=238,   GND=2*,   SDA=285,   SCL=141,  VDDSPD=284
DDR3:    SA0=117,   SA1=237,   SA2=119,   GND=2*,   SDA=238,   SCL=118,  VDDSPD=236
DDR2:    SA0=239,   SA1=240,   SA2=101,   GND=4*,   SDA=119,   SCL=120,  VDDSPD=238
DDR:      SA0=181,   SA1=182,   SA2=183,   GND=3*,   SDA=91,     SCL=92,    VDDSPD=184
SDRAM: SA0=165,   SA1=166,   SA2=167,   GND=1*,   SDA=82,     SCL=83,    VDDSPD=168
 
* There are multiple GND pins on DIMMs, the table shows just one of them for each RAM type.
 
DDR4 DIMM pins locations:
 

(photo borrowed from wikipedia)
 
Obviously don't solder wires directly to DIMM contacts or motherboard solder points, get a spare slot from components resellers, like Digikey, or get a DDR4 DIMM adapter, like the one pictured below. Those are cheap, and have pins labeled for easy identification.
 

 
 

Part 2 - Firmware and basic tests

Upload firmware to your Arduino once everything is assembled. Both files are required. Make sure the values in SpdReaderWriterSettings.h match the pins names you used if your pins differ from the ones in the guide.
 
After uploading, open Serial Monitor (press Ctrl+Shift+M in Arduino IDE), change Baud Rate to 115200, enter 

t

into the text field and press "send" or enter key. If everything works, you'll receive an "!" in response. Enter

v

to get firmware version number.
 
 

Part 3 - Windows GUI application

 
Latest GUI application can always be found here:
 
https://github.com/1a2m3/.D-Reader-Writer/releases
 
The application requires .NET framework 4.5 or later to be installed. Supported OSs are Windows Vista SP2 and up. The application is compiled for x86 architecture, so both 32 bit and 64 bit OSs are supported. (Windows XP and older OSs aren't supported).
 
Once your device is assembled and tested, start the program. By default it scans for connected device on startup and detected devices will show up in the "Device" button submenu:
 

 
Click on the device identified by its serial port name and EEPROM address detected on its I2C bus to start working with it.
 
 

Part 4 - Windows Console application

 
The program can read and write bytes, and enable or disable write protection. The operation depends on its command line arguments. The supported arguments are:
 

1. /help

2. /find

3. /scan <PORT>

4. /read <PORT> <ADDRESS#> <filepath> /silent

5. /write <PORT> <ADDRESS#> <FILEPATH> /silent

6. /writeforce <PORT> <ADDRESS#> <FILEPATH> /silent

7. /enablewriteprotection <PORT>

8. /enablewriteprotection <PORT> <block#>

9. /disablewriteprotection <PORT>

10. /enablepermanentwriteprotection <PORT> <ADDRESS#>

 
The parameters in CAPS are mandatory. Parameter <filepath> is optional when 

/read

switch is used, output will be printed to console only.
 
You'll need to know two parameters to work your DIMM - port name and EEPROM address. To find out what port your device is using, run this command:
 

SpdReaderWriter.exe /find

 
If everything works, you'll get a port name your device is connected to:
 

 
Found Device on Serial Port: COM3

 
In my case it is COM3. If the program can't find any devices, make sure the sketch is properly uploaded to your Arduino and no other application is using your Arduino's serial port - that includes Arduino IDE Serial Monitor. Close it, if you have it open.
 
With a DDR4 DIMM present you'll want to scan your device for EEPROM addresses on I2C bus. With SA0-SA2 connected to ground, the address will be 80, however, it is still recommended to run this test to ensure the EEPROM is detected:
 

SpdReaderWriter.exe /scan COM3

 
In most cases, if everything is fine, you'll see a device at address 80 detected:
 

 
Found EEPROM at address: 80

 
When I used DDR4 slots cut out of an old motherboard with both DIMMs populated, both were detected at addresses 80 and 82, even though I soldered wires to one slot only:
 

 
 
 
Found EEPROM at address: 80
Found EEPROM at address: 82

 
To read SPD from your DIMM, run:
 

SpdReaderWriter.exe /read COM3 80

 
This will output SPD contents in HEX on screen. Plain and simple.
 

Reading EEPROM at address 80

000: 23 10 0C 02 84 19 00 08 00 00 00 03 01 03 00 00
010: 00 00 08 0C F4 1B 00 00 6C 6C 6C 11 00 74 20 08
020: 00 05 70 03 00 A8 1E 2B 2B 00 00 00 00 00 00 00
--edited on purpose--
1D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
1E0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
1F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Read 512 bytes from EEPROM at address 80 on port COM3 in 1547 ms

 
To save SPD to file, add a file path at the end. File path can be absolute or relative. If file path has spaces in it, enclose it in "double quotes":
 

SpdReaderWriter.exe /read COM3 80 C:\temp\spdoutput.bin

SpdReaderWriter.exe /read COM3 80 "C:\temp\my ddr4 spd file.bin"

 

Reading EEPROM at address 80 to C:\temp\my ddr4 spd file.bin

000: 23 10 0C 02 84 19 00 08 00 00 00 03 01 03 00 00
--edited on purpose--
1F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Read 512 bytes from EEPROM at address 80 on port COM3 in 1562 ms to file "C:\temp\my ddr4 spd file.bin"

 
Edit your SPD in a HEX editor or any specialized program, like Thaiphoon Burner. 
 
To write your new SPD to DIMM, run:
 

SpdReaderWriter.exe /write COM3 80 C:\temp\newspd.bin

 
EEPROMs have limited number of write cycles, sometimes between 10,000 and 1,000,000. By default, the program writes bytes only if they differ from existing values. By doing that, it first reads a byte and if it matches the input value, the write operation is skipped. Byte is written only it it needs to. If you want to force writes, regardless of existing SPD data, use 

/writeforce

switch instead of

/write

. It will take a bit longer (5-10 s.) because of required delays after each write.
 

Writing "C:\temp\my ddr4 spd file.bin" (512 bytes) to EEPROM at address 80

000: 23 10 0C 02 84 19 00 08 00 00 00 03 01 03 00 00
010: 00 00 08 0C F4 1B 00 00 6C 6C 6C 11 00 74 20 08
020: 00 05 70 03 00 A8 1E 2B 2B 00 00 00 00 00 00 00
--edited on purpose--
1D0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
1E0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
1F0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Written 512 bytes to EEPROM at address 80 on port COM3 in 7093 ms

 
Optionally, to hide progress you may add 

/silent

switch at the end after a file path is specified when using

/read

,

/write

, or

/writeforce

switches:
 

SpdReaderWriter.exe /read COM3 80 C:\temp\spdoutput.bin /silent

SpdReaderWriter.exe /write COM3 80 C:\temp\newspd.bin /silent

 
You may protect the entire EEPROM from writing with this command:
 

SpdReaderWriter.exe /enablewriteprotection COM3

 
If the blocks weren't write-protected previously, you'll receive a response like this:
 

 
Block 0 is now read-only
Block 1 is now read-only
Block 2 is now read-only
Block 3 is now read-only

 
Or enable write protection on each individual block by specifying block number (0-3):
 

SpdReaderWriter.exe /enablewriteprotection COM3 0

SpdReaderWriter.exe /enablewriteprotection COM3 2

 
Each block specifies a section of 128 bytes. Block 0 is bytes at offset 0-127, block 1 is bytes 128-255, and so on.
 
Please note the address isn't used, only port number. That's because RSWP commands don't use addresses, all devices on the I2C bus will act simultaneously.
 
To clear write protection, run the following command:
 

SpdReaderWriter.exe /disablewriteprotection COM3

 
Again, the device address isn't used.
 
Once write-protection is cleared, you'll see this response:
 

Write protection successfully disabled.

 
To enable permanent write protection, run this command:

SpdReaderWriter.exe /enablepermanentwriteprotection COM3 80

 
Please note permanent protection can be enabled on most DDR3 and some DDR2 modules. DDR4 does not support permanent software write protection.
 
That's all for now.
 
I'm always open to suggestions and comments. Feel free to report any bugs or ask to add any feature you'd like to see in the project, whether it's related to hardware, firmware, or applications.

Almost there, everything is working properly now.
 

 



 

Look what came in the mail today after weeks months of waiting. Now I no longer have to use slots I cut out of a dead motherboard.
 

 

Cool GTX
sounds interesting
 
can damaged/ corrupted SPD code be overwritten -- Recovered ? 

Cause you know someone will OC it too far

 
Yes, provided you have a backup of correct SPD data, or a working DIMM.
 
I'll aslo implement a CRC checker into the Windows app. In won't be accessible via command line switches initially, but rather by calling a function directly.

Edit: Arduino sketch is posted, link is in the first post.

Thanks. So far I haven't encountered any write protected EEPROMs, in fact the DIMMs I used in my tests use EEPROMs which lack permanent write protection capabilities.
 
I'll start working on software write protection enabling/disabling capabilities soon. It will require a couple more components added to the circuit and an additional 9V source.
 
The project is complete. Windows binary and sources + updated Arduino sketch are up.
 
Links are in the first post.

Update: 22.05.2020 - now with write protection reversing and enabling options 
 
Updated schematics, description, firmware, binary, and sources are in the first post.

Nice work.
I'd suggest upload your project to github or smth, so others can contribute too :)

looks like you have made some good progress on your project

The GUI version is being finalized, and it works fine, but looks horrible.
 
But I'm a programmer, not a UI designer, so there's my excuse for bad interface.

 
Reader:

 
Writer:

 
Write protection:

 
Debug:




 
 
 

New experimental feature - Thaiphoon Burner dump import.
 

 
I just realized the free version of Thaiphoon Burner doesn't allow SPDs to be saved in binary format, so I implemented an SPD importer in my program which will allow loaded SPDs to be read from Thaiphoon Burner.
 
I'm still testing it, once I'm sure it is bug-free, I'll post updated sources and binaries.
 
 

We only allow posts in the English language so your posts will be deleted. 

Contact EVENT_N is used only by the thermal sensor and is not used when reading and writing the SPD chip:

Hi!
Unfortunately, I can not respond to 5 forum posts personally.
While working with the SpdReaderWriterGUI.exe program, I had 2 comments.
1. The program starts for a very long time from 10 to 40 seconds on my computer:

2. 2.After starting, the program sometimes freezes with an error message:

 

a213m
I don't know where you got that information from, but connecting SA1 to VDD would only change device address, which is relevant for read and write operations. Device addresses are ignored when issuing RSWP commands. Just because bit 2 of CWP command is set to 1, doesn't mean SA1 has to be physically wired to VDDSPD. None of EEPROMS I've encountered with require SA1 or SA2 to be configured in specific way for write protection operations. Only SA0 has to be connected to high voltage source.

Perhaps I do not understand the document correctly.
_ttp://www.softnology.biz/tips_pswprotection.html
Here is the document I referenced earlier: _ttp://propretor.narod.ru/Arduino/4_01_04R21.pdf