diff --git a/app/uart.c b/app/uart.c
index c80456f..f39671b 100644
--- a/app/uart.c
+++ b/app/uart.c
@@ -429,8 +429,8 @@ bool UART_IsCommandAvailable(void)
     uint16_t CRC;
     uint16_t CommandLength;
     uint16_t DmaLength = DMA_CH0->ST & 0xFFFU;
-    char a[2]="OK";
-    UART_Send((uint8_t *)&a,2);
+    char d[2]="OK";
+    UART_Send((uint8_t *)&d,2);
 
     while (1)
     {
@@ -443,8 +443,8 @@ bool UART_IsCommandAvailable(void)
 
         if (gUART_WriteIndex == DmaLength)
             return false;
-        char a[2]="2K";
-        UART_Send((uint8_t *)&a,2);
+        char c[2]="2K";
+        UART_Send((uint8_t *)&c,2);
         if (gUART_WriteIndex < DmaLength)
             CommandLength = DmaLength - gUART_WriteIndex;
         else
@@ -514,8 +514,8 @@ bool UART_IsCommandAvailable(void)
     }
 
     CRC = UART_Command.Buffer[Size] | (UART_Command.Buffer[Size + 1] << 8);
-    char a[2]="3K";
-    UART_Send((uint8_t *)&a,2);
+    char b[2]="3K";
+    UART_Send((uint8_t *)&b,2);
     return (CRC_Calculate(UART_Command.Buffer, Size) != CRC) ? false : true;
 }