Decode Xbox One I2C traffic of SMBUS2/3 busses, to easily see POST codes in your logic analyzer traces.

shell> sigrok-cli -i i2c_trace.sr -P "i2c:sda=SB SDA:scl=SB SCL,max6958,xbox_one_sb_post" -P "i2c:sda=SOC SDA:scl=SOC SCL,xbox_one_soc_post" -A "xbox_one_soc_post,xbox_one_sb_post"
xbox_one_sb_post-1: SP : 0x42
xbox_one_sb_post-1: SP : 0x43
xbox_one_sb_post-1: SP : 0x44
xbox_one_sb_post-1: SP : 0x45
xbox_one_sb_post-1: SP : 0x4b
xbox_one_sb_post-1: SP : 0x4c
xbox_one_sb_post-1: SP : 0x50
xbox_one_sb_post-1: SP : 0x53
xbox_one_sb_post-1: CPU: 0x100
xbox_one_sb_post-1: SP : 0x5c
xbox_one_sb_post-1: CPU: 0x101
xbox_one_sb_post-1: CPU: 0x102
xbox_one_sb_post-1: CPU: 0x103
xbox_one_soc_post-1: CODE=00000042
xbox_one_soc_post-1: CODE=00000042
xbox_one_soc_post-1: CODE=00000043
xbox_one_soc_post-1: CODE=00000044

1. Locate the sigrok decoders directory:

   sigrok-cli --version  # Find libsigrokdecode path
   # Usually: ~/.local/share/libsigrokdecode/decoders/ or /usr/share/libsigrokdecode/decoders/

2. Create decoder directory:

   mkdir -p ~/.local/share/libsigrokdecode/decoders/{max6958,xbox_one_sb_post,xbox_one_soc_post}

3. Copy decoder files:

   cp max6958/* ~/.local/share/libsigrokdecode/decoders/max6958/
   cp xbox_one_sb_post/* ~/.local/share/libsigrokdecode/decoders/xbox_one_sb_post/
   cp xbox_one_soc_post/* ~/.local/share/libsigrokdecode/decoders/xbox_one_soc_post/

4. Verify installation:

   sigrok-cli -L | grep -E 'xbox_one_sb_post|xbox_one_soc_post|max6958'

• Create / load a capture file in PulseView

• Add protocol decoder(s)

• Choose I2C as the base decoder

• Click on the added decoder label

• Assign the correct channels for SCL/SDA, then hit Stack Decoder.

NOTE: You can also name your decoder accordingly.

• Choose the sub-decoder(s)

For Xbox One SMBUS2 (SB), stack:

• MAX6958
• Xbox One SB POST Code

For Xbox One SMBUS3 (SoC), stack:

• Xbox One SoC POST Code

The following pictures show the flow for SMBUS2

• Ensure decoders are python3.4 compliant, sigrok/pulseview windows builds are bundled with that version of python!

The following is targeted at Linux (sigrok decoder directory path & script)

cargo install watchexec
# Re-execute deploy.sh on changes to *.py files
watchexec -f '*.py' ./deploy.sh