diff --git a/boards/arm/stm32/stm32ldiscovery/src/stm32_lcd.c b/boards/arm/stm32/stm32ldiscovery/src/stm32_lcd.c
index 7a0ac5dcafc..7b05554a5ae 100644
--- a/boards/arm/stm32/stm32ldiscovery/src/stm32_lcd.c
+++ b/boards/arm/stm32/stm32ldiscovery/src/stm32_lcd.c
@@ -581,7 +581,7 @@ static int slcd_setcontrast(uint8_t contrast)
     }
 
   regval = getreg32(STM32_LCD_FCR);
-  regval &= !LCD_FCR_CC_MASK;
+  regval &= ~LCD_FCR_CC_MASK;
   regval |= contrast << LCD_FCR_CC_SHIFT;
   putreg32(regval, STM32_LCD_FCR);