Diff: main.cpp

Revision:

1:633244b5186b

Parent:

0:84e316af0e0c

Child:

5:65094452a0c5

diff -r 84e316af0e0c -r 633244b5186b main.cpp
--- a/main.cpp	Tue Jun 06 08:34:35 2017 +0000
+++ b/main.cpp	Tue Jun 06 22:28:33 2017 +0100
@@ -21,7 +21,7 @@
 #define GNSS_WAIT_TIME_SECONDS 120
 #define STOP_TIME_SECONDS 5
 #define STANDBY_TIME_SECONDS 5
-#define _CHECK_TALKER(s) ((buffer[3] == s[0]) && (buffer[4] == s[1]) && (buffer[5] == s[2]))
+#define CHECK_TALKER(s) ((buffer[3] == s[0]) && (buffer[4] == s[1]) && (buffer[5] == s[2]))
 #define BACKUP_SRAM_STRING "Back from Standby mode!"
 
 // Put the time at the start of back-up SRAM
@@ -45,114 +45,119 @@
 
 /* This example program for the u-blox C030 board demonstrates the use of
  * the low power driver.  It waits for GPS to obtain the time, entering Stop
- * mode while waiting for GPS results and, once the time has been obtained,
- * it enters Standby mode for some time, putting stored information (the time
- * and a string) into backup SRAM where they will be kept until the end of
- * Standby mode.  Progress may be monitored with a serial terminal
- * running at 9600 baud. The LED on the C030 board will turn green when this
- * program is operating correctly, flash blue when GNSS time is received,
- * and turn red if GNSS time was not received or there is a failure.
+ * mode while waiting for the GPS to return results and, once the time has
+ * been obtained, it enters Standby mode, putting some stored information
+ * into backup SRAM where it will be kept until the end of Standby mode.
+ * Progress may be monitored with a serial terminal running at 9600 baud.
+ * The LED on the C030 board will turn green when this program is operating
+ * correctly, flash white when GNSS time is received, and turn red if GNSS
+ * time was not received or there is a failure.
  */
 
+// Get the time from GNSS
+static bool gnssGetTime(GnssSerial *gnss)
+{
+    char buffer[256];
+    bool gotTime = false;
+    int gnssReturnCode;
+    int32_t length;
+    
+    while ((gnssReturnCode = gnss->getMessage(buffer, sizeof(buffer))) > 0) {
+        length = LENGTH(gnssReturnCode);
+
+        if ((PROTOCOL(gnssReturnCode) == GnssParser::NMEA) && (length > 6)) {
+            // Talker is $GA=Galileo $GB=Beidou $GL=Glonass $GN=Combined $GP=GNSS
+            if ((buffer[0] == '$') || buffer[1] == 'G') {
+                if (CHECK_TALKER("GGA") || CHECK_TALKER("GNS")) {
+                    const char *timeString = NULL;
+                    // Retrieve the time
+                    timeString = gnss->findNmeaItemPos(1, buffer, buffer + length);
+                    if (timeString != NULL) {
+                        gotTime = true;
+                        printf("\nGNSS: time is %.6s (UTC).\n", timeString);
+                        ledBlue = 0;
+                        ledGreen = 0;
+                        ledRed = 0;
+                        wait_ms(1000);        
+                    }
+                }
+            }
+        }
+    }
+    
+    return gotTime;
+}
+
+// Main
 int main()
 {
     GnssSerial gnss;
     LowPower lowPower;
-    time_t timeNow;
-    int gnssReturnCode;
-    char buffer[256];
     bool gotTime = false;
 
     // First exit Debug mode on the chip, otherwise it will not be
     // able to enter Standby mode
     lowPower.exitDebugMode();
 
+    ledGreen = 0;
+    ledRed = 1;
+    ledBlue = 1;
+        
     // Initialise GNSS
-    gnss.init();
-
-    if (time(NULL) != 0) {
-        // If the RTC is running, we must have been awake previously
-        printf ("Awake from Standby mode after %d second(s).\n", 
-                (int) (time(NULL) - timeNow));
-        printf ("Backup RAM contains \"%.*s\".\n", sizeof(BACKUP_SRAM_STRING),
-                 backupSram);
-        ledGreen = 0;
-        ledRed = 1;
-        ledBlue = 1;
-        
-    } else {
-        printf("\n\nStarting up from a cold start.\n");
-        printf("IMPORTANT: this code puts the STM32F4xx chip into its lowest power state.\n");
-        printf("The ability to do this is affected by the state of the debug chip on the C030\n");
-        printf("board. To be sure that this code executes correctly, you must completely power\n");
-        printf("off the board after downloading code, and power it back on again.\n\n");
-    }
+    if (gnss.init()) {
+        if (time(NULL) != 0) {
+            // If the RTC is running, we must have been awake previously
+            printf ("Awake from Standby mode after %d second(s).\n", 
+                    (int) (time(NULL) - timeNow));
+            printf ("Backup RAM contains \"%.*s\".\n\n", sizeof(BACKUP_SRAM_STRING),
+                     backupSram);
+        } else {
+            printf("\n\nStarting up from a cold start.\n");
+            printf("IMPORTANT: this code puts the STM32F4xx chip into its lowest power state.\n");
+            printf("The ability to do this is affected by the state of the debug chip on the C030\n");
+            printf("board. To be sure that this code executes correctly, you must completely power\n");
+            printf("off the board after downloading code, and power it back on again.\n\n");
+        }
 
-    printf ("Waiting up to %d second(s) for GNSS to receive the time...\n",
-            GNSS_WAIT_TIME_SECONDS);
-    for (uint32_t x = 0; (x < GNSS_WAIT_TIME_SECONDS) && !gotTime;
-          x+= STOP_TIME_SECONDS) {
-        while ((gnssReturnCode = gnss.getMessage(buffer, sizeof(buffer))) > 0) {
-            int32_t length = LENGTH(gnssReturnCode);
-
-            if ((PROTOCOL(gnssReturnCode) == GnssParser::NMEA) && (length > 6)) {
-                // talker is $GA=Galileo $GB=Beidou $GL=Glonass $GN=Combined $GP=GNSS
-                if ((buffer[0] == '$') || buffer[1] == 'G') {
-                    if (_CHECK_TALKER("GGA") || _CHECK_TALKER("GNS")) {
-                        const char *timeString = NULL;
+        printf ("Waiting up to %d second(s) for GNSS to receive the time...\n", GNSS_WAIT_TIME_SECONDS);
+        for (uint32_t x = 0; (x < GNSS_WAIT_TIME_SECONDS) && !gotTime; x+= STOP_TIME_SECONDS) {
+            gotTime = gnssGetTime(&gnss);
 
-                        // Retrieve the time
-                        timeString = gnss.findNmeaItemPos(1, buffer,
-                                                          buffer + length);
-                        if (timeString != NULL) {
-                            gotTime = true;
-                            printf("GNSS: time is %.6s.\n",timeString);
-                            ledGreen = 1;
-                            ledRed = 1;
-                            ledBlue = 0;
-                            wait_ms(1000);        
-                        }
-                    }
-                }
+            if (!gotTime) {
+                printf ("  Entering Stop mode for %d second(s) while waiting...\n", STOP_TIME_SECONDS);
+                // Let the printf leave the building
+                wait_ms(100);
+                time_t y = time(NULL);
+                lowPower.enterStop(STOP_TIME_SECONDS * 1000);
+                printf ("  Awake from Stop mode after %d second(s).\n", (int) (time(NULL) - y));
             }
         }
 
+        ledGreen = 1;
+        ledRed = 1;
+        ledBlue = 1;
         if (!gotTime) {
-            printf ("  Entering Stop mode for %d second(s) while waiting...\n",
-                    STOP_TIME_SECONDS);
-            // Let the printf leave the building
-            wait_ms(100);
-            timeNow = time(NULL);
-            lowPower.enterStop(STOP_TIME_SECONDS * 1000);
-            printf ("  Awake from Stop mode after %d second(s).\n",
-                    (int) (time(NULL) - timeNow));
+            ledRed = 0;
         }
-    }
+        
+        printf ("\nPutting \"%s\" into BKPSRAM...\n", BACKUP_SRAM_STRING);
+        memcpy (backupSram, BACKUP_SRAM_STRING, sizeof(BACKUP_SRAM_STRING));
 
-    ledGreen = 1;
-    ledRed = 1;
-    ledBlue = 1;
-    if (!gotTime) {
-        ledRed = 0;
+        printf ("Entering Standby mode, losing all RAM contents, for %d second(s)...\n\n", STANDBY_TIME_SECONDS);
+        // Let the printf leave the building
+        wait_ms(100);
+        // We will return at the start of main() when the Standby time expires
+        timeNow = time(NULL);
+        lowPower.enterStandby(STANDBY_TIME_SECONDS * 1000);
+    } else {
+        printf("Unable to initialise GNSS.\n");
     }
     
-    printf ("\nPutting \"%s\" into BKPSRAM...\n", BACKUP_SRAM_STRING);
-    memcpy (backupSram, BACKUP_SRAM_STRING, sizeof(BACKUP_SRAM_STRING));
-
-    printf ("Entering Standby mode for %d second(s)...\n", STANDBY_TIME_SECONDS);
-    // Let the printf leave the building
-    wait_ms(100);
-    // We will return at the start of main() when the Standby time expires
-    lowPower.enterStandby(STANDBY_TIME_SECONDS * 1000);
-
+    ledRed = 0;
     ledGreen = 1;
-    ledRed = 0;
     ledBlue = 1;
-
     printf("Should never get here.\n");
     MBED_ASSERT(false);
-
-    return 0;
 }
 
 // End Of File
\ No newline at end of file