TLV Writer Documentation
Table of Contents
where to get
Overview
This script writes TLV (Type-Length-Value) structured data into an I2C EEPROM. It supports a variety of system-specific keys that define metadata for the device.
The script:
Builds TLV-formatted payloads.
Writes the data into an EEPROM via I2C.
Supports custom-defined keys.
Calculates and appends a CRC checksum to ensure data integrity.
Dependencies
To ensure all required dependencies are installed, run:
sudo apt update
sudo apt install python3 python3-smbusthis will:
Install Python 3 if it is not already installed.
Install smbus for I2C communication.
Usage
python3 TLV_write.py <i2c_bus> <eeprom_address> [--yes] [-b] <key> <value> <key> <value> ...Arguments
Argument | Description |
|---|---|
i2c_bus | The I2C bus number. |
eeprom_address | The EEPROM address (hex or decimal). |
--yes | Automatically confirms the operation (skips user confirmation). |
-b | Writes the TLV data to a binary file ( |
<key> <value> | One or more key-value pairs to write to EEPROM. |
Example Usage
For example if we want the following data to appear in DMI:
Handle 0xXXXX, DMI type 1, XX bytes
System Information
Manufacturer: XXXXX
Product Name: MySystem
Version: 1.0
Serial Number: XXXXXX
UUID: XXXXXX-XXXXX-XXXXX-XXXXX-XXXXX
Wake-up Type: XXXXXXXXXXXX
SKU Number: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
Family: XXXXXXXXXXXXXXXXXXXXXXXWe want to run the following command (Note that bus 3 address 0X50 is used in this example):
python3 TLVwriter.py 3 0x50 TLV_CODE_SYS_NAME "MySystem" TLV_CODE_SYS_VERSION "1.0"eeprom example for this :
python3 TLVwriter.py 3 0x50 TLV_CODE_SYS_NAME "EmbeddedDevice" \
TLV_CODE_SYS_SKU "ED-2024" \
TLV_CODE_SYS_SERIAL_NUMBER "SN123456789" \
TLV_CODE_SYS_VERSION "01.02" \
TLV_CODE_FAMILY "Industrial" \
TLV_CODE_MANUF_NAME "Solid-Run" \
TLV_CODE_MANUF_DATE "2024-03-11" \
TLV_CODE_PLATFORM_NAME "Bedrock-IPC"00: 54 6c 76 49 6e 66 6f 00 01 65 00 30 0e 45 6d 62 TlvInfo.?e.0?Emb
10: 65 64 64 65 64 44 65 76 69 63 65 31 07 45 44 2d eddedDevice1?ED-
20: 32 30 32 34 32 0b 53 4e 31 32 33 34 35 36 37 38 20242?SN12345678
30: 39 33 05 30 31 2E 30 32 20 0a 49 6e 64 75 73 74 93?01.02 ?Indust
40: 72 69 61 6c 25 09 73 6f 6c 69 64 2d 72 75 6e 23 rial%.solid-run#
50: 0a 32 30 32 34 2d 30 33 2d 31 31 24 0b 42 65 64 .2024-03-11$.Bed
60: 72 6f 63 6b 2d 49 50 43 fe 04 6e 7e c0 fd 00 00 rock-IPC??n~??
70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
80: ……
header
version
Total Payload Length (little endian)
Type
Length
Value
crc checksum TLV
Finding the I2C Bus Number
To determine the correct I2C bus number, run the following command:
sudo i2cdetect -y 1If no EEPROM device is found, repeat the command with different bus numbers (e.g., 3, 4, 5 etc.) until you detect an address 0x50 or 0x56. Once found, use the corresponding bus number in the script.
Example:
sudo i2cdetect -y 3If the output shows:
0 1 2 3 4 5 6 7 8 9 A B C D E F
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: 50 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --Then bus 3 and address 0x50 should be used in the script.
SolidRun Ltd.