diff --git a/arch/arm/src/lpc17xx/lpc17_lowputc.c b/arch/arm/src/lpc17xx/lpc17_lowputc.c
index 1ea68287bc5..ba90c1ff6a6 100644
--- a/arch/arm/src/lpc17xx/lpc17_lowputc.c
+++ b/arch/arm/src/lpc17xx/lpc17_lowputc.c
@@ -141,9 +141,11 @@
  *
  *   PCLK = CCLK / divisor
  *
- * Ignoring the fractional divider for now.
+ * Ignoring the fractional divider for now. (If you want to extend this driver
+ * to support the fractional divider, see lpc43xx_uart.c.  The LPC43xx uses
+ * the same peripheral and that logic could easily leveraged here).
  *
- * Check divisor == 1.  This works if the upper limit is met	
+ * Check divisor == 1.  This works if the upper limit is met:
  *
  *   DL < 0xffff, or
  *   PCLK / BAUD / 16 < 0xffff, or
diff --git a/arch/arm/src/lpc17xx/lpc17_serial.c b/arch/arm/src/lpc17xx/lpc17_serial.c
index ced1c5d665a..5ea6348e086 100644
--- a/arch/arm/src/lpc17xx/lpc17_serial.c
+++ b/arch/arm/src/lpc17xx/lpc17_serial.c
@@ -791,7 +791,9 @@ static inline void lpc17_uart3config(uint32_t clkdiv)
  *     BAUD = PCLK / (16 * DL), or
  *     DL   = PCLK / BAUD / 16
  *
- *   Ignoring the fractional divider for now.
+ *   Ignoring the fractional divider for now. (If you want to extend this driver
+ *   to support the fractional divider, see lpc43xx_uart.c.  The LPC43xx uses
+ *   the same peripheral and that logic could easily leveraged here).
  *
  ************************************************************************************/