diff --git a/lib/oled_ssd1306.c b/lib/oled_ssd1306.c
index 08368ff..8c9003f 100644
--- a/lib/oled_ssd1306.c
+++ b/lib/oled_ssd1306.c
@@ -29,24 +29,24 @@
 /* own libraries */
 #include "global.h" // global utilities
 #include "oled_ssd1306.h" // OLED definitions
-#include "i2c_master.h" // I2C header and definitions
+#include "i2c_master.h" // I²C header and definitions
 
-/** SSD1306 OLED display I2C slave address */
+/** SSD1306 OLED display I²C slave address */
 static uint8_t oled_ssd1306_slave_addr = 0x3c;
 
-/** @defgroup oled_ssd1306_i2c I2C peripheral to communicate with the SSD1306 OLED
+/** @defgroup oled_ssd1306_i2c I²C peripheral to communicate with the SSD1306 OLED
  *  @{
  */
-#define OLED_SSD1306_I2C I2C1 /**< I2C peripheral */
+#define OLED_SSD1306_I2C I2C1 /**< I²C peripheral */
 /** @} */
 
 bool oled_ssd1306_setup(uint8_t slave_addr)
 {
-	if (!i2c_master_check_signals(OLED_SSD1306_I2C)) { // check if there are pull-ups to operator I2C
+	if (!i2c_master_check_signals(OLED_SSD1306_I2C)) { // check if there are pull-ups to operator I²C
 		return false;
 	}
-	oled_ssd1306_slave_addr = slave_addr; // save I2C slave address of SSD1306
-	i2c_master_setup(OLED_SSD1306_I2C, 400); // setup I2C bus ( SSD1306 supports an I2C cleck up to 400 kHz)
+	oled_ssd1306_slave_addr = slave_addr; // save I²C slave address of SSD1306
+	i2c_master_setup(OLED_SSD1306_I2C, 400); // setup I²C bus (SSD1306 supports an I²C clock up to 400 kHz)
 	const uint8_t oled_init[] = {
 		0x00, // control byte: continuous (multiple byes), command
 		0xae, // Set Display ON/OFF: OFF
@@ -87,7 +87,7 @@ void oled_ssd1306_off(void)
 		0x80, // control byte: no continuation, command
 		0xae, // Set Display ON/OFF: OFF
 	}; // command to switch off display
-	i2c_master_slave_write(OLED_SSD1306_I2C, oled_ssd1306_slave_addr, false, oled_display_off, LENGTH(oled_display_off)); // sent command to switch onff display
+	i2c_master_slave_write(OLED_SSD1306_I2C, oled_ssd1306_slave_addr, false, oled_display_off, LENGTH(oled_display_off)); // sent command to switch font display
 }
 
 void oled_ssd1306_test(void)
diff --git a/lib/oled_ssd1306.h b/lib/oled_ssd1306.h
index e6fe9b9..238c771 100644
--- a/lib/oled_ssd1306.h
+++ b/lib/oled_ssd1306.h
@@ -20,8 +20,9 @@
  */
 
 /** setup OLED display
- *  @param[in] slave_addr I2C slave address of SSD1306 device (least significant 7-bit)
- *  @return if the display setup is successful, else the display is probably not on the I2C bus
+ *  @param[in] slave_addr I²C slave address of SSD1306 device (least significant 7-bit)
+ *  @return if the display setup is successful, else the display is probably not on the I²C bus
+ *  @warning only one display on the I²C bus is currently supported
  */
 bool oled_ssd1306_setup(uint8_t slave_addr);
 /** switch OLED display on */