Fix workaround logic

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@1124 42af7a65-404d-4744-a932-0658087f49c3

1 files changed, 12 insertions, 6 deletions

diff --git a/nuttx/configs/mcu123-lpc214x/src/up_spi.c b/nuttx/configs/mcu123-lpc214x/src/up_spi.c
index 9e201a5a0..0997aa01b 100644
--- a/nuttx/configs/mcu123-lpc214x/src/up_spi.c
+++ b/nuttx/configs/mcu123-lpc214x/src/up_spi.c
@@ -154,11 +154,16 @@ static void spi_select(FAR struct spi_dev_s *dev, boolean selected)
       while (!(getreg8(LPC214X_SPI1_SR) & LPC214X_SPI1SR_TNF));
       putreg16(0xff, LPC214X_SPI1_DR);
 
-      /* Then wait until TX FIFO and TX shift buffer are empty */
+      /* Wait until TX FIFO and TX shift buffer are empty */
 
       while (getreg8(LPC214X_SPI1_SR) & LPC214X_SPI1SR_BSY);
+
+      /* Wait until RX FIFO is not empty */
+
       while (!(getreg8(LPC214X_SPI1_SR) & LPC214X_SPI1SR_RNE));
 
+      /* Then read and discard bytes until the RX FIFO is empty */
+
       do
         {
           (void)getreg16(LPC214X_SPI1_DR);
@@ -290,7 +295,7 @@ static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const ubyte *buffer, siz
         }
     }
 
-  /* Then discard all card responses until the TX FIFO is emptied. */
+  /* Then discard all card responses until the RX & TX FIFOs are emptied. */
 
   do
     {
@@ -304,12 +309,13 @@ static void spi_sndblock(FAR struct spi_dev_s *dev, FAR const ubyte *buffer, siz
           (void)getreg16(LPC214X_SPI1_DR);
         }
 
-      /* There is a race condition where TFE may go FALSE just before
-       * RNE goes true.  The nasty little delay in the following solves
-       * that (it could probably be tuned to improve performance).
+      /* There is a race condition where TFE may go TRUE just before
+       * RNE goes true and this loop terminates prematurely.  The nasty little
+       * delay in the following solves that (it could probably be tuned
+       * to improve performance).
        */
 
-      else if ((sr & LPC214X_SPI1SR_TFE) == 0)
+      else if ((sr & LPC214X_SPI1SR_TFE) != 0)
         {
           up_udelay(100);
           sr = getreg8(LPC214X_SPI1_SR);