u-blox / Mbed OS example-low-power-sleep

Program to demonstrate the use of the LowPowerSleep class on the u-blox C030 platform.

Dependencies:   gnss low-power-sleep

main.cpp@6:356d18b0e389, 2017-07-31 (annotated)

Committer:
rob.meades@u-blox.com
Date:
Mon Jul 31 11:19:44 2017 +0100
Revision:
6:356d18b0e389
Parent:
5:65094452a0c5 
Point mbed-os library at ARMmbed master.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
RobMeades 0:84e316af0e0c 1 /* mbed Microcontroller Library
RobMeades 0:84e316af0e0c 2 * Copyright (c) 2017 u-blox
RobMeades 0:84e316af0e0c 3 *
RobMeades 0:84e316af0e0c 4 * Licensed under the Apache License, Version 2.0 (the "License");
RobMeades 0:84e316af0e0c 5 * you may not use this file except in compliance with the License.
RobMeades 0:84e316af0e0c 6 * You may obtain a copy of the License at
RobMeades 0:84e316af0e0c 7 *
RobMeades 0:84e316af0e0c 8 * http://www.apache.org/licenses/LICENSE-2.0
RobMeades 0:84e316af0e0c 9 *
RobMeades 0:84e316af0e0c 10 * Unless required by applicable law or agreed to in writing, software
RobMeades 0:84e316af0e0c 11 * distributed under the License is distributed on an "AS IS" BASIS,
RobMeades 0:84e316af0e0c 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
RobMeades 0:84e316af0e0c 13 * See the License for the specific language governing permissions and
RobMeades 0:84e316af0e0c 14 * limitations under the License.
RobMeades 0:84e316af0e0c 15 */
RobMeades 0:84e316af0e0c 16
RobMeades 0:84e316af0e0c 17 #include "mbed.h"
RobMeades 0:84e316af0e0c 18 #include "low_power.h"
RobMeades 0:84e316af0e0c 19 #include "gnss.h"
RobMeades 0:84e316af0e0c 20
RobMeades 0:84e316af0e0c 21 #define GNSS_WAIT_TIME_SECONDS 120
RobMeades 0:84e316af0e0c 22 #define STOP_TIME_SECONDS 5
RobMeades 0:84e316af0e0c 23 #define STANDBY_TIME_SECONDS 5
rob.meades@u-blox.com 1:633244b5186b 24 #define CHECK_TALKER(s) ((buffer[3] == s[0]) && (buffer[4] == s[1]) && (buffer[5] == s[2]))
RobMeades 0:84e316af0e0c 25 #define BACKUP_SRAM_STRING "Back from Standby mode!"
RobMeades 0:84e316af0e0c 26
RobMeades 0:84e316af0e0c 27 // Put the time at the start of back-up SRAM
RobMeades 0:84e316af0e0c 28 BACKUP_SRAM
RobMeades 0:84e316af0e0c 29 static time_t timeNow;
RobMeades 0:84e316af0e0c 30
RobMeades 0:84e316af0e0c 31 // The rest of backup SRAM
RobMeades 0:84e316af0e0c 32 BACKUP_SRAM
RobMeades 0:84e316af0e0c 33 static char backupSram[BACKUP_SRAM_SIZE - sizeof (timeNow)];
RobMeades 0:84e316af0e0c 34
RobMeades 0:84e316af0e0c 35 // LEDs
RobMeades 0:84e316af0e0c 36 DigitalOut ledRed(LED1, 1);
RobMeades 0:84e316af0e0c 37 DigitalOut ledGreen(LED2, 1);
RobMeades 0:84e316af0e0c 38 DigitalOut ledBlue(LED3, 1);
RobMeades 0:84e316af0e0c 39
RobMeades 0:84e316af0e0c 40 /* IMPORTANT: this code puts the STM32F4xx chip into its lowest power state.
RobMeades 0:84e316af0e0c 41 * The ability to do this is affected by the state of the debug chip on the C030
RobMeades 0:84e316af0e0c 42 * board. To be sure that this code executes correctly, you MUST completely
RobMeades 0:84e316af0e0c 43 * power off the board after downloading code, and power it back on again.
RobMeades 0:84e316af0e0c 44 */
RobMeades 0:84e316af0e0c 45
RobMeades 0:84e316af0e0c 46 /* This example program for the u-blox C030 board demonstrates the use of
rob.meades@u-blox.com 5:65094452a0c5 47 * the low power driver. It waits for GNSS to obtain the time, entering Stop
rob.meades@u-blox.com 5:65094452a0c5 48 * mode while waiting for the GNSS to return results and, once the time has
rob.meades@u-blox.com 1:633244b5186b 49 * been obtained, it enters Standby mode, putting some stored information
rob.meades@u-blox.com 5:65094452a0c5 50 * into backup SRAM where it will remain safe during Standby mode.
rob.meades@u-blox.com 5:65094452a0c5 51 * Note: the use of GNSS is in no way related to the LowPowerSleep class,
rob.meades@u-blox.com 5:65094452a0c5 52 * it's simply something to do in this demonstration.
rob.meades@u-blox.com 1:633244b5186b 53 * Progress may be monitored with a serial terminal running at 9600 baud.
rob.meades@u-blox.com 1:633244b5186b 54 * The LED on the C030 board will turn green when this program is operating
rob.meades@u-blox.com 1:633244b5186b 55 * correctly, flash white when GNSS time is received, and turn red if GNSS
rob.meades@u-blox.com 1:633244b5186b 56 * time was not received or there is a failure.
RobMeades 0:84e316af0e0c 57 */
RobMeades 0:84e316af0e0c 58
rob.meades@u-blox.com 1:633244b5186b 59 // Get the time from GNSS
rob.meades@u-blox.com 1:633244b5186b 60 static bool gnssGetTime(GnssSerial *gnss)
rob.meades@u-blox.com 1:633244b5186b 61 {
rob.meades@u-blox.com 1:633244b5186b 62 char buffer[256];
rob.meades@u-blox.com 1:633244b5186b 63 bool gotTime = false;
rob.meades@u-blox.com 1:633244b5186b 64 int gnssReturnCode;
rob.meades@u-blox.com 1:633244b5186b 65 int32_t length;
rob.meades@u-blox.com 1:633244b5186b 66
rob.meades@u-blox.com 1:633244b5186b 67 while ((gnssReturnCode = gnss->getMessage(buffer, sizeof(buffer))) > 0) {
rob.meades@u-blox.com 1:633244b5186b 68 length = LENGTH(gnssReturnCode);
rob.meades@u-blox.com 1:633244b5186b 69
rob.meades@u-blox.com 1:633244b5186b 70 if ((PROTOCOL(gnssReturnCode) == GnssParser::NMEA) && (length > 6)) {
rob.meades@u-blox.com 1:633244b5186b 71 // Talker is $GA=Galileo $GB=Beidou $GL=Glonass $GN=Combined $GP=GNSS
rob.meades@u-blox.com 1:633244b5186b 72 if ((buffer[0] == '$') || buffer[1] == 'G') {
rob.meades@u-blox.com 1:633244b5186b 73 if (CHECK_TALKER("GGA") || CHECK_TALKER("GNS")) {
rob.meades@u-blox.com 1:633244b5186b 74 const char *timeString = NULL;
rob.meades@u-blox.com 1:633244b5186b 75 // Retrieve the time
rob.meades@u-blox.com 1:633244b5186b 76 timeString = gnss->findNmeaItemPos(1, buffer, buffer + length);
rob.meades@u-blox.com 1:633244b5186b 77 if (timeString != NULL) {
rob.meades@u-blox.com 1:633244b5186b 78 gotTime = true;
rob.meades@u-blox.com 1:633244b5186b 79 printf("\nGNSS: time is %.6s (UTC).\n", timeString);
rob.meades@u-blox.com 1:633244b5186b 80 ledBlue = 0;
rob.meades@u-blox.com 1:633244b5186b 81 ledGreen = 0;
rob.meades@u-blox.com 1:633244b5186b 82 ledRed = 0;
rob.meades@u-blox.com 1:633244b5186b 83 wait_ms(1000);
rob.meades@u-blox.com 1:633244b5186b 84 }
rob.meades@u-blox.com 1:633244b5186b 85 }
rob.meades@u-blox.com 1:633244b5186b 86 }
rob.meades@u-blox.com 1:633244b5186b 87 }
rob.meades@u-blox.com 1:633244b5186b 88 }
rob.meades@u-blox.com 1:633244b5186b 89
rob.meades@u-blox.com 1:633244b5186b 90 return gotTime;
rob.meades@u-blox.com 1:633244b5186b 91 }
rob.meades@u-blox.com 1:633244b5186b 92
rob.meades@u-blox.com 1:633244b5186b 93 // Main
RobMeades 0:84e316af0e0c 94 int main()
RobMeades 0:84e316af0e0c 95 {
RobMeades 0:84e316af0e0c 96 GnssSerial gnss;
RobMeades 0:84e316af0e0c 97 LowPower lowPower;
RobMeades 0:84e316af0e0c 98 bool gotTime = false;
RobMeades 0:84e316af0e0c 99
RobMeades 0:84e316af0e0c 100 // First exit Debug mode on the chip, otherwise it will not be
RobMeades 0:84e316af0e0c 101 // able to enter Standby mode
RobMeades 0:84e316af0e0c 102 lowPower.exitDebugMode();
RobMeades 0:84e316af0e0c 103
rob.meades@u-blox.com 1:633244b5186b 104 ledGreen = 0;
rob.meades@u-blox.com 1:633244b5186b 105 ledRed = 1;
rob.meades@u-blox.com 1:633244b5186b 106 ledBlue = 1;
rob.meades@u-blox.com 1:633244b5186b 107
RobMeades 0:84e316af0e0c 108 // Initialise GNSS
rob.meades@u-blox.com 1:633244b5186b 109 if (gnss.init()) {
rob.meades@u-blox.com 1:633244b5186b 110 if (time(NULL) != 0) {
rob.meades@u-blox.com 1:633244b5186b 111 // If the RTC is running, we must have been awake previously
rob.meades@u-blox.com 1:633244b5186b 112 printf ("Awake from Standby mode after %d second(s).\n",
rob.meades@u-blox.com 1:633244b5186b 113 (int) (time(NULL) - timeNow));
rob.meades@u-blox.com 1:633244b5186b 114 printf ("Backup RAM contains \"%.*s\".\n\n", sizeof(BACKUP_SRAM_STRING),
rob.meades@u-blox.com 1:633244b5186b 115 backupSram);
rob.meades@u-blox.com 1:633244b5186b 116 } else {
rob.meades@u-blox.com 1:633244b5186b 117 printf("\n\nStarting up from a cold start.\n");
rob.meades@u-blox.com 1:633244b5186b 118 printf("IMPORTANT: this code puts the STM32F4xx chip into its lowest power state.\n");
rob.meades@u-blox.com 1:633244b5186b 119 printf("The ability to do this is affected by the state of the debug chip on the C030\n");
rob.meades@u-blox.com 1:633244b5186b 120 printf("board. To be sure that this code executes correctly, you must completely power\n");
rob.meades@u-blox.com 1:633244b5186b 121 printf("off the board after downloading code, and power it back on again.\n\n");
rob.meades@u-blox.com 1:633244b5186b 122 }
RobMeades 0:84e316af0e0c 123
rob.meades@u-blox.com 1:633244b5186b 124 printf ("Waiting up to %d second(s) for GNSS to receive the time...\n", GNSS_WAIT_TIME_SECONDS);
rob.meades@u-blox.com 1:633244b5186b 125 for (uint32_t x = 0; (x < GNSS_WAIT_TIME_SECONDS) && !gotTime; x+= STOP_TIME_SECONDS) {
rob.meades@u-blox.com 1:633244b5186b 126 gotTime = gnssGetTime(&gnss);
RobMeades 0:84e316af0e0c 127
rob.meades@u-blox.com 1:633244b5186b 128 if (!gotTime) {
rob.meades@u-blox.com 1:633244b5186b 129 printf (" Entering Stop mode for %d second(s) while waiting...\n", STOP_TIME_SECONDS);
rob.meades@u-blox.com 1:633244b5186b 130 // Let the printf leave the building
rob.meades@u-blox.com 1:633244b5186b 131 wait_ms(100);
rob.meades@u-blox.com 1:633244b5186b 132 time_t y = time(NULL);
rob.meades@u-blox.com 1:633244b5186b 133 lowPower.enterStop(STOP_TIME_SECONDS * 1000);
rob.meades@u-blox.com 1:633244b5186b 134 printf (" Awake from Stop mode after %d second(s).\n", (int) (time(NULL) - y));
RobMeades 0:84e316af0e0c 135 }
RobMeades 0:84e316af0e0c 136 }
RobMeades 0:84e316af0e0c 137
rob.meades@u-blox.com 1:633244b5186b 138 ledGreen = 1;
rob.meades@u-blox.com 1:633244b5186b 139 ledRed = 1;
rob.meades@u-blox.com 1:633244b5186b 140 ledBlue = 1;
RobMeades 0:84e316af0e0c 141 if (!gotTime) {
rob.meades@u-blox.com 1:633244b5186b 142 ledRed = 0;
RobMeades 0:84e316af0e0c 143 }
rob.meades@u-blox.com 1:633244b5186b 144
rob.meades@u-blox.com 1:633244b5186b 145 printf ("\nPutting \"%s\" into BKPSRAM...\n", BACKUP_SRAM_STRING);
rob.meades@u-blox.com 1:633244b5186b 146 memcpy (backupSram, BACKUP_SRAM_STRING, sizeof(BACKUP_SRAM_STRING));
RobMeades 0:84e316af0e0c 147
rob.meades@u-blox.com 1:633244b5186b 148 printf ("Entering Standby mode, losing all RAM contents, for %d second(s)...\n\n", STANDBY_TIME_SECONDS);
rob.meades@u-blox.com 1:633244b5186b 149 // Let the printf leave the building
rob.meades@u-blox.com 1:633244b5186b 150 wait_ms(100);
rob.meades@u-blox.com 1:633244b5186b 151 // We will return at the start of main() when the Standby time expires
rob.meades@u-blox.com 1:633244b5186b 152 timeNow = time(NULL);
rob.meades@u-blox.com 1:633244b5186b 153 lowPower.enterStandby(STANDBY_TIME_SECONDS * 1000);
rob.meades@u-blox.com 1:633244b5186b 154 } else {
rob.meades@u-blox.com 1:633244b5186b 155 printf("Unable to initialise GNSS.\n");
RobMeades 0:84e316af0e0c 156 }
RobMeades 0:84e316af0e0c 157
rob.meades@u-blox.com 1:633244b5186b 158 ledRed = 0;
RobMeades 0:84e316af0e0c 159 ledGreen = 1;
RobMeades 0:84e316af0e0c 160 ledBlue = 1;
RobMeades 0:84e316af0e0c 161 printf("Should never get here.\n");
RobMeades 0:84e316af0e0c 162 MBED_ASSERT(false);
RobMeades 0:84e316af0e0c 163 }
RobMeades 0:84e316af0e0c 164
RobMeades 0:84e316af0e0c 165 // End Of File