diff --git a/README.org b/README.org
index d07f96d566636670b2298b968fbc21153537225d..a678f37005958a456b9dadc46ccba6ba874f1dbc 100644
--- a/README.org
+++ b/README.org
@@ -21,6 +21,10 @@
 | Timers (general purpose)  | 3     |
 | Timers (advanced control) | 1     |
 | CPU frequency             | 72MHz |
+| I2C                       | 2     |
+
+The =I2C2= is used (=PB10=/=SCL=, =PB11=/=SDA=) to communicate with
+the TB6612FNG motor driver.
 
 *** Flash-memory organization