From 80f869ce8ad1492c2c4bfa08c48d5b50dca70b24 Mon Sep 17 00:00:00 2001
From: "Austin St. Aubin" <AustinSaintAubin@gmail.com>
Date: Sun, 29 Apr 2012 20:46:21 -0500
Subject: [PATCH] Added Standby and Wakeup fuctions for powering down and
 powering back up the GPS

---
 Adafruit_GPS.cpp | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/Adafruit_GPS.cpp b/Adafruit_GPS.cpp
index c0b45ab..8e5e7ed 100644
--- a/Adafruit_GPS.cpp
+++ b/Adafruit_GPS.cpp
@@ -24,6 +24,7 @@ volatile uint8_t lineidx=0;
 volatile char *currentline;
 volatile char *lastline;
 volatile boolean recvdflag;
+volatile boolean inStandbyMode;
 
 
 boolean Adafruit_GPS::parse(char *nmea) {
@@ -344,3 +345,27 @@ boolean Adafruit_GPS::LOCUS_ReadStatus(void) {
 
   return true;
 }
+
+// Standby Mode Switches
+boolean Adafruit_GPS::standby(void) {
+  if (inStandbyMode) {
+    return false;  // Returns false if already in standby mode, so that you do not wake it up by sending commands to GPS
+  }
+  else {
+    inStandbyMode = true;
+    sendCommand(PMTK_STANDBY);
+    //return waitForSentence(PMTK_STANDBY_SUCCESS);  // don't seem to be fast enough to catch the message, or something else just is not working
+    return true;
+  }
+}
+
+boolean Adafruit_GPS::wakeup(void) {
+  if (inStandbyMode) {
+   inStandbyMode = false;
+    sendCommand("");  // send byte to wake it up
+    return waitForSentence(PMTK_AWAKE);
+  }
+  else {
+      return false;  // Returns false if not in standby mode, nothing to wakeup
+  }
+}
\ No newline at end of file