SLAU847F October 2022 – March 2026 MSPM0L1105 , MSPM0L1106 , MSPM0L1116 , MSPM0L1117 , MSPM0L1227 , MSPM0L1227-Q1 , MSPM0L1228 , MSPM0L1228-Q1 , MSPM0L1303 , MSPM0L1304 , MSPM0L1304-Q1 , MSPM0L1305 , MSPM0L1305-Q1 , MSPM0L1306 , MSPM0L1306-Q1 , MSPM0L1343 , MSPM0L1344 , MSPM0L1345 , MSPM0L1346 , MSPM0L2116 , MSPM0L2117 , MSPM0L2227 , MSPM0L2227-Q1 , MSPM0L2228 , MSPM0L2228-Q1
Both UNICOMM modules are configured for I2C communication in the IPMODE register. Controller-Target pairings are supported.
Both UNICOMM modules belong to the same SPG instance. Check the Unicomm Block Diagram to see which SPG instance the UNICOMM instance belongs to.
To create an I2C pair within an SPG:
Select the UNICOMM to be used as the first I2C (controller) in the loopback and find the local index number of the UNICOMM instance in the SPG.
Select the UNICOMM to be used as the second I2C (target) in the loopback and find the local index number of the UNICOMM instance in the SPG.
Write the first UNICOMM index to PAIR0.CTL
Write the second UNICOMM index to PAIR0.TARGET
Enable the loopback by writing a '1' to PAIR0.EN
The I2C pairing feature establishes a controller-target relationship between two UNICOMM modules while maintaining connection to external pins.
When an I2C pair is enabled:
- The SDA/SCL signals from the UNICOMM module specified in PAIR.TARGET are actively propagated to the device pins
- The SDA/SCL signals from the UNICOMM module specified in PAIR.CTL are automatically driven to their IDLE states by the module's internal logic
This configuration allows the TARGET module to control the physical I2C bus while preventing bus contention. Although the PAIR.CTL module's pins are driven to IDLE states internally, these physical pins can still be reassigned through the device's pin multiplexing (pinmux) configuration to serve alternative functions in other peripheral modules if needed.