1 files changed, 9 insertions, 1 deletions
diff --git a/include/arch/stm32l4xxx/peripherals/spi.h b/include/arch/stm32l4xxx/peripherals/spi.h
index e5b44fe..478664e 100644
--- a/include/arch/stm32l4xxx/peripherals/spi.h
+++ b/include/arch/stm32l4xxx/peripherals/spi.h
@@ -92,7 +92,15 @@ typedef __IO struct {
   /* spi data register. Really only the least-significant 16 bits are used.
    * reading from this register reads from the Rx FIFO while writing to it
    * writes to the Tx FIFO. */
-  __IO uint32_t d_r;
+  union {
+    /* The lower 8 its of the spi data register. */
+    __IO uint8_t dl_r;
+
+    /* The data register. */
+    __IO uint16_t d_r;
+  };
+
+  __IO uint16_t unused;
 
   /* spi CRC polynomial register. */
   uint32_t crcp_r;