Diff: main.cpp

Revision:

0:84e316af0e0c

Child:

1:633244b5186b

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Tue Jun 06 08:34:35 2017 +0000
@@ -0,0 +1,158 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2017 u-blox
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "mbed.h"
+#include "low_power.h"
+#include "gnss.h"
+
+#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 BACKUP_SRAM_STRING "Back from Standby mode!"
+
+// Put the time at the start of back-up SRAM
+BACKUP_SRAM
+static time_t timeNow;
+
+// The rest of backup SRAM
+BACKUP_SRAM
+static char backupSram[BACKUP_SRAM_SIZE - sizeof (timeNow)];
+
+// LEDs
+DigitalOut ledRed(LED1, 1);
+DigitalOut ledGreen(LED2, 1);
+DigitalOut ledBlue(LED3, 1);
+
+/* IMPORTANT: this code puts the STM32F4xx chip into its lowest power state.
+ * The ability to do this is affected by the state of the debug chip on the C030
+ * board. To be sure that this code executes correctly, you MUST completely
+ * power off the board after downloading code, and power it back on again.
+ */
+
+/* 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.
+ */
+
+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();
+
+    // 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");
+    }
+
+    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;
+
+                        // 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);
+            timeNow = time(NULL);
+            lowPower.enterStop(STOP_TIME_SECONDS * 1000);
+            printf ("  Awake from Stop mode after %d second(s).\n",
+                    (int) (time(NULL) - timeNow));
+        }
+    }
+
+    ledGreen = 1;
+    ledRed = 1;
+    ledBlue = 1;
+    if (!gotTime) {
+        ledRed = 0;
+    }
+    
+    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);
+
+    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