diff --git a/src/main.rs b/src/main.rs
index f968280..1a9c947 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -37,6 +37,7 @@ async fn main(_spawner: Spawner) {
     let mut i2c_cfg = i2c::Config::default();
     i2c_cfg.sda_pullup = false;
     i2c_cfg.scl_pullup = false;
+    i2c_cfg.frequency = time::Hertz(400_000);
     let mut i2c = i2c::I2c::new(p.I2C2, p.PB13, p.PB14, p.GPDMA1_CH0, p.GPDMA1_CH1, Irqs, i2c_cfg);
 
     let cal = calibration::Calibration::read(&mut i2c).await;