diff --git a/arch/arm/src/stm32l4/stm32l4_adc.c b/arch/arm/src/stm32l4/stm32l4_adc.c
index 16cd42fb07..a4796ce09a 100644
--- a/arch/arm/src/stm32l4/stm32l4_adc.c
+++ b/arch/arm/src/stm32l4/stm32l4_adc.c
@@ -1640,7 +1640,7 @@ static int adc_extsel_set(FAR struct stm32_dev_s *priv, uint32_t extcfg)
       setbits = (extsel | exten);
       clrbits = (ADC_CFGR_EXTEN_MASK | ADC_CFGR_EXTSEL_MASK);
 
-      ainfo("Initializing extsel = 0x%08x\n", extsel);
+      ainfo("Initializing extsel = 0x%08" PRIx32 "\n", extsel);
 
       /* Write register */