diff --git a/main.c b/main.c
index 2d36126..a6e6eca 100644
--- a/main.c
+++ b/main.c
@@ -336,6 +336,16 @@ we will only be able to provide 1 extension block since we can only respond to o
 		SCL_SNK_PU_PORT->ODR.reg |= SCL_SNK_PU_PIN; // pull up SCL line
 		SCL_SNK_PU_PORT->CR1.reg |= SCL_SNK_PU_PIN; // switch pin to push pull
 		SCL_SNK_PU_PORT->DDR.reg |= SCL_SNK_PU_PIN; // switch pin to output
+		if (0 == (SDA_SNK_PORT->IDR.reg & SDA_SNK_PIN)) { // SDA line is stuck
+			puts ("bus clear ");
+			// perform bus clear
+			for (uint8_t i = 0; i < 9; i++) {
+				SCL_SNK_PORT->ODR.reg &= ~SCL_SNK_PIN;
+				wait_10us(1);
+				SCL_SNK_PORT->ODR.reg |= SCL_SNK_PIN;
+				wait_10us(1);
+			}
+		}
 		uint8_t i2c_rc = 1; // if the complete read succeeded
 		if (!softi2c_master_setup(400)) { // start the I²C master to talk to sink
 			i2c_rc = 2;