updated comments

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1220 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 9 insertions, 1 deletions

diff --git a/nuttx/drivers/serialirq.c b/nuttx/drivers/serialirq.c
index ba859c2ef..f7503e4cc 100644
--- a/nuttx/drivers/serialirq.c
+++ b/nuttx/drivers/serialirq.c
@@ -84,13 +84,21 @@ void uart_xmitchars(FAR uart_dev_t *dev)
 
   while (dev->xmit.head != dev->xmit.tail && uart_txready(dev))
     {
+      /* Send the next byte */
+
       uart_send(dev, dev->xmit.buffer[dev->xmit.tail]);
 
+      /* Increment the tail index */
+
       if (++(dev->xmit.tail) >= dev->xmit.size)
         {
           dev->xmit.tail = 0;
         }
 
+      /* A byte was removed from the buffer.  Inform any waiters
+       * there there is space available.
+       */
+
       if (dev->xmitwaiting)
         {
           dev->xmitwaiting = FALSE;
@@ -139,7 +147,7 @@ void uart_recvchars(FAR uart_dev_t *dev)
 
       dev->recv.buffer[dev->recv.head] = uart_receive(dev, &status);
 
-      /* Increment the index */
+      /* Increment the head index */
 
       dev->recv.head = nexthead;
       if (++nexthead >= dev->recv.size)