diff --git a/arch/arm/src/a1x/a1x_lowputc.c b/arch/arm/src/a1x/a1x_lowputc.c
index 1c10464ba5..37bd3bea50 100644
--- a/arch/arm/src/a1x/a1x_lowputc.c
+++ b/arch/arm/src/a1x/a1x_lowputc.c
@@ -150,10 +150,13 @@
 #define CONSOLE_FCR_VALUE (UART_FCR_RT_HALF | UART_FCR_XFIFOR |\
                            UART_FCR_RFIFOR | UART_FCR_FIFOE)
 
-/* SCLK is the UART input clock */
+/* SCLK is the UART input clock.
+ *
+ * Through experimentation, it has been found that the serial clock is
+ * OSC24M
+ */
 
-#define A1X_SCLK 0
-#warning What is the correct value of SCLK
+#define A1X_SCLK 24000000
 
 /* The output baud rate is equal to the serial clock (SCLK) frequency divided
  * by sixteen times the value of the baud rate divisor, as follows:
diff --git a/arch/arm/src/a1x/a1x_serial.c b/arch/arm/src/a1x/a1x_serial.c
index e23a39e6c9..924534082b 100644
--- a/arch/arm/src/a1x/a1x_serial.c
+++ b/arch/arm/src/a1x/a1x_serial.c
@@ -77,10 +77,13 @@
 
 #if defined(USE_SERIALDRIVER) && defined(HAVE_UART_DEVICE)
 
-/* SCLK is the UART input clock */
+/* SCLK is the UART input clock.
+ *
+ * Through experimentation, it has been found that the serial clock is
+ * OSC24M
+ */
 
-#define A1X_SCLK 0
-#warning What is the correct value of SCLK
+#define A1X_SCLK 24000000
 
 /****************************************************************************
  * Private Types