From 681ade41fa9b06b55cfb6c2d3b9a63168bc18491 Mon Sep 17 00:00:00 2001
From: liquidraver <504870+liquidraver@users.noreply.github.com>
Date: Thu, 21 May 2026 22:00:27 +0200
Subject: [PATCH] =?UTF-8?q?=20GPS=20UI=20screen=20changes=20=20-open=20the?=
 =?UTF-8?q?=20screen=20with=20no=20fix=20=E2=86=92=20"Lat=20|=20Lon"=20pla?=
 =?UTF-8?q?ceholder;=20=20=20first=20fix=20arrives=20=E2=86=92=20lat/lon?=
 =?UTF-8?q?=20for=204=20s=20=E2=86=92=20altitude=20for=204=20s=20=E2=86=92?=
 =?UTF-8?q?=20repeat;=20=20=20lose=20fix=20=E2=86=92=20state=20resets,=20n?=
 =?UTF-8?q?ext=20fix=20starts=20fresh=20on=20lat/lon.?=
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Content-Transfer-Encoding: 8bit

---
 .../helpers/ui-joystick/screens/system.cpp    | 23 +++++++++++--------
 1 file changed, 14 insertions(+), 9 deletions(-)

diff --git a/zephcore/helpers/ui-joystick/screens/system.cpp b/zephcore/helpers/ui-joystick/screens/system.cpp
index 8a8ea3e..e0d53eb 100644
--- a/zephcore/helpers/ui-joystick/screens/system.cpp
+++ b/zephcore/helpers/ui-joystick/screens/system.cpp
@@ -616,6 +616,7 @@ bool AdvertScreen::handleInput(char key)
 #define GPS_HEADING_MIN_M  5.0f   /* min move to update heading (m) */
 #define GPS_MAX_SPEED_KMH  300.0f
 #define GPS_HEADING_HOLD_MS  4000
+#define ALT_CYCLE_MS         4000  /* lat/lon ↔ altitude flip period while a fix is held */
 
 GPSSettingsScreen::GPSSettingsScreen(JoystickUITask *task, mesh::RTCClock *rtc)
 	: _task(task), _rtc(rtc), _selected(0),
@@ -661,20 +662,12 @@ void GPSSettingsScreen::onDisplayOn()
 
 void GPSSettingsScreen::sampleGPS()
 {
-	/* Cycle between position and altitude view every 4 seconds */
-	uint32_t now = k_uptime_get_32();
-	if (_alt_cycle_ms == 0) {
-		_alt_cycle_ms = now + GPS_HEADING_HOLD_MS;
-	} else if (now >= _alt_cycle_ms) {
-		_show_alt = !_show_alt;
-		_alt_cycle_ms = now + GPS_HEADING_HOLD_MS;
-	}
-
 	if (!_task->isGPSAvailable() || !_task->getGPSState()) return;
 	struct gps_position pos;
 	gps_get_position(&pos);
 	if (!pos.valid) return;
 
+	uint32_t now = k_uptime_get_32();
 	if (now - _last_sample_ms < 1000) return;
 
 	int32_t lat = (int32_t)(pos.latitude_ndeg  / 1000LL);
@@ -746,6 +739,15 @@ int GPSSettingsScreen::render(JoystickDisplay &display)
 		snprintf(satellites_line, sizeof(satellites_line), "Sat: %d (%s)", sat, fix_str);
 
 		if (has_fix) {
+			/* Each fresh fix starts on lat/lon, flips every ALT_CYCLE_MS. */
+			uint32_t now = k_uptime_get_32();
+			if (_alt_cycle_ms == 0) {
+				_alt_cycle_ms = now + ALT_CYCLE_MS;
+			} else if (now >= _alt_cycle_ms) {
+				_show_alt = !_show_alt;
+				_alt_cycle_ms = now + ALT_CYCLE_MS;
+			}
+
 			if (_show_alt) {
 				float alt_m = (float)pos.altitude_mm / 1000.0f;
 				snprintf(lat_lon_line, sizeof(lat_lon_line), "Alt: %.1f m", (double)alt_m);
@@ -764,6 +766,9 @@ int GPSSettingsScreen::render(JoystickDisplay &display)
 				snprintf(speed_line, sizeof(speed_line), "%.1f km/h", (double)_speed_kmh);
 			}
 		} else {
+			/* No fix — reset cycle so the next fix starts on lat/lon. */
+			_alt_cycle_ms = 0;
+			_show_alt = false;
 			snprintf(lat_lon_line, sizeof(lat_lon_line), "Lat | Lon");
 			snprintf(speed_line, sizeof(speed_line), "Speed | Compass");
 		}