Improve sensortag external flash power management:

* Explicitly put in deep sleep on device startup
* Verify that the flash has actually dropped to deep sleep
* Update CLK pin to match the one used on the v1.2 sensortag

Obsoletes and Closes #988

platform/srf06-cc26xx/sensortag/board.c

@@ -142,6 +142,9 @@ board_init()
 
   buzzer_init();
 
+  /* Make sure the external flash is in the lower power mode */
+  ext_flash_init();
+
   lpm_register_module(&sensortag_module);
 
   /* Re-enable interrupt if initially enabled. */

platform/srf06-cc26xx/sensortag/board.h

@@ -156,7 +156,7 @@
  */
 #define BOARD_IOID_FLASH_CS       IOID_14
 #define BOARD_FLASH_CS            (1 << BOARD_IOID_FLASH_CS)
-#define BOARD_SPI_CLK_FLASH       IOID_11
+#define BOARD_IOID_SPI_CLK_FLASH  IOID_17
 /** @} */
 /*---------------------------------------------------------------------------*/
 /**

platform/srf06-cc26xx/sensortag/ext-flash.c

@@ -72,7 +72,7 @@
 /* Part specific constants */
 
 #define BLS_MANUFACTURER_ID       0xEF
-#define BLS_DEVICE_ID             0x11
+#define BLS_DEVICE_ID             0x12
 
 #define BLS_PROGRAM_PAGE_SIZE      256
 #define BLS_ERASE_SECTOR_SIZE     4096
@@ -140,50 +140,8 @@ wait_ready(void)
 }
 /*---------------------------------------------------------------------------*/
 /**
- * \brief Put the device in power save mode. No access to data; only
- *        the status register is accessible.
- * \return True when SPI transactions succeed
- */
-static bool
-power_down(void)
-{
-  uint8_t cmd;
-  bool success;
-
-  cmd = BLS_CODE_DP;
-  select();
-  success = board_spi_write(&cmd, sizeof(cmd));
-  deselect();
-
-  return success;
-}
-/*---------------------------------------------------------------------------*/
-/**
- * \brief    Take device out of power save mode and prepare it for normal operation
- * \return   True if the command was written successfully
- */
-static bool
-power_standby(void)
-{
-  uint8_t cmd;
-  bool success;
-
-  cmd = BLS_CODE_RDP;
-  select();
-  success = board_spi_write(&cmd, sizeof(cmd));
-
-  if(success) {
-    success = wait_ready() == 0;
-  }
-
-  deselect();
-
-  return success;
-}
-/*---------------------------------------------------------------------------*/
-/**
- * Verify the flash part.
- * @return True when successful.
+ * \brief Verify the flash part.
+ * \return True when successful.
  */
 static bool
 verify_part(void)
@@ -210,6 +168,57 @@ verify_part(void)
   return true;
 }
 /*---------------------------------------------------------------------------*/
+/**
+ * \brief Put the device in power save mode. No access to data; only
+ *        the status register is accessible.
+ */
+static void
+power_down(void)
+{
+  uint8_t cmd;
+  uint8_t i;
+
+  cmd = BLS_CODE_DP;
+  select();
+  board_spi_write(&cmd, sizeof(cmd));
+  deselect();
+
+  i = 0;
+  while(i < 10) {
+    if(!verify_part()) {
+      /* Verify Part failed: Device is powered down */
+      return;
+    }
+    i++;
+  }
+
+  /* Should not be required */
+  deselect();
+}
+/*---------------------------------------------------------------------------*/
+/**
+ * \brief    Take device out of power save mode and prepare it for normal operation
+ * \return   True if the command was written successfully
+ */
+static bool
+power_standby(void)
+{
+  uint8_t cmd;
+  bool success;
+
+  cmd = BLS_CODE_RDP;
+  select();
+  success = board_spi_write(&cmd, sizeof(cmd));
+
+  if(success) {
+    success = wait_ready() == 0;
+  }
+
+  deselect();
+
+  return success;
+}
+/*---------------------------------------------------------------------------*/
 /**
  * \brief Enable write.
  * \return Zero when successful.
@@ -232,7 +241,7 @@ write_enable(void)
 bool
 ext_flash_open()
 {
-  board_spi_open(4000000, BOARD_SPI_CLK_FLASH);
+  board_spi_open(4000000, BOARD_IOID_SPI_CLK_FLASH);
 
   /* GPIO pin configuration */
   ti_lib_ioc_pin_type_gpio_output(BOARD_IOID_FLASH_CS);
@@ -406,4 +415,11 @@ ext_flash_test(void)
   return ret;
 }
 /*---------------------------------------------------------------------------*/
+void
+ext_flash_init()
+{
+  ext_flash_open();
+  ext_flash_close();
+}
+/*---------------------------------------------------------------------------*/
 /** @} */

platform/srf06-cc26xx/sensortag/ext-flash.h

@@ -54,6 +54,8 @@ bool ext_flash_open(void);
 
 /**
  * \brief Close the storage driver
+ *
+ * This call will put the device in its lower power mode (power down).
  */
 void ext_flash_close(void);
 
@@ -94,6 +96,17 @@ bool ext_flash_write(size_t offset, size_t length, const uint8_t *buf);
  * \return True when successful.
  */
 bool ext_flash_test(void);
+
+/**
+ * \brief Initialise the external flash
+ *
+ * This function will explicitly put the part in its lowest power mode
+ * (power-down).
+ *
+ * In order to perform any operation, the caller must first wake the device
+ * up by calling ext_flash_open()
+ */
+void ext_flash_init(void);
 /*---------------------------------------------------------------------------*/
 #endif /* EXT_FLASH_H_ */
 /*---------------------------------------------------------------------------*/