Adding comment for future RTOS/multitasking integration

diff --git a/drivers/ssp.c b/drivers/ssp.c
index 190ba1d..cdc1007 100644 (file)
--- a/drivers/ssp.c
+++ b/drivers/ssp.c
@@ -18,13 +18,22 @@
  *
  *************************************************************************** */
 
-
+/*
+ * Note for multitasking and/or real-time OS design :
+ * Four of the functions in this driver may spend some time waiting for external
+ *   events or other tasks.
+ * The concerned functions are spi_get_mutex(), spi_transfer_single_frame(),
+ *   spi_transfer_words() and spi_transfer_bytes().
+ * These functions should call the scheduler at some point to avoid using more
+ * time than required or even hang the system.
+ */
 
 /***************************************************************************** */
 /*                SSP                                                          */
 /***************************************************************************** */
 
-/* SSP/SPI driver for the SSP bus integrated module of the LPC122x.
+/*
+ * SSP/SPI driver for the SSP bus integrated module of the LPC122x.
  * Refer to LPC122x documentation (UM10441.pdf) for more information.
  */
 
@@ -120,8 +129,8 @@ void spi_release_mutex(uint8_t ssp_num)
  *   the device.
  * Note : the SSP device number is not checked, thus a value above the number of SSP
  *   devices present on the micro-controller may break your programm.
- *   Double check the value of the ssp_num parameter. The check is made on the call to
- *   ssp_master_on() or ssp_slave_on().
+ *   Double check the value of the ssp_num parameter. The check is made only once when
+ *   ssp_master_on() or ssp_slave_on() is called.
  * This function does not take care of the SPI chip select.
  */
 uint16_t spi_transfer_single_frame(uint8_t ssp_num, uint16_t data)