diff --git a/boards/arm/stm32/hymini-stm32v/src/stm32_r61505u.c b/boards/arm/stm32/hymini-stm32v/src/stm32_r61505u.c
index e9d1972f1e..22510fcceb 100644
--- a/boards/arm/stm32/hymini-stm32v/src/stm32_r61505u.c
+++ b/boards/arm/stm32/hymini-stm32v/src/stm32_r61505u.c
@@ -809,7 +809,7 @@ static void lcd_backlight(void)
 
   /* Select the output polarity level == HIGH */
 
-  ccer &= !ATIM_CCER_CC2P;
+  ccer &= ~ATIM_CCER_CC2P;
 
   /* Enable channel 2 */
 
diff --git a/boards/arm/stm32/hymini-stm32v/src/stm32_ssd1289.c b/boards/arm/stm32/hymini-stm32v/src/stm32_ssd1289.c
index 788a81c3b8..ba82a96f4e 100644
--- a/boards/arm/stm32/hymini-stm32v/src/stm32_ssd1289.c
+++ b/boards/arm/stm32/hymini-stm32v/src/stm32_ssd1289.c
@@ -307,7 +307,7 @@ static void init_lcd_backlight(void)
 
   /* Select the output polarity level == HIGH */
 
-  ccer &= !ATIM_CCER_CC2P;
+  ccer &= ~ATIM_CCER_CC2P;
 
   /* Enable channel 2 */
 
diff --git a/boards/arm/stm32/viewtool-stm32f107/src/stm32_ssd1289.c b/boards/arm/stm32/viewtool-stm32f107/src/stm32_ssd1289.c
index 88be606edc..0e9d3cddb6 100644
--- a/boards/arm/stm32/viewtool-stm32f107/src/stm32_ssd1289.c
+++ b/boards/arm/stm32/viewtool-stm32f107/src/stm32_ssd1289.c
@@ -375,7 +375,7 @@ static void init_lcd_backlight(void)
 
   /* Select the output polarity level == HIGH */
 
-  ccer &= !ATIM_CCER_CC2P;
+  ccer &= ~ATIM_CCER_CC2P;
 
   /* Enable channel 2 */