Added an option for the SPI transmit pattern.

git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@14963 27425a3e-05d8-49a3-a47f-9c15f0e5edd8

os/hal/ports/STM32/LLD/SPIv2/hal_spi_v2_lld.c

@@ -433,7 +433,7 @@ msg_t spi_lld_start(SPIDriver *spip) {
   msg_t msg;
 
   /* Resetting TX pattern source.*/
-  spip->txsource = 0xFFFFFFFFU;
+  spip->txsource = (uint32_t)STM32_SPI_FILLER_PATTERN;
 
   /* If in stopped state then enables the SPI and DMA clocks.*/
   if (spip->state == SPI_STOP) {

os/hal/ports/STM32/LLD/SPIv2/hal_spi_v2_lld.h

@@ -103,6 +103,13 @@
 #define STM32_SPI_USE_SPI6                  FALSE
 #endif
 
+/**
+ * @brief   Filler pattern used when there is nothing to transmit.
+ */
+#if !defined(STM32_SPI_FILLER_PATTERN) || defined(__DOXYGEN__)
+#define STM32_SPI_FILLER_PATTERN            0xFFFFFFFFU
+#endif
+
 /**
  * @brief   SPI1 interrupt priority level setting.
  */