display improvements

zephcore/CMakeLists.txt

@@ -698,6 +698,7 @@ endif()
 if(CONFIG_ZEPHCORE_UI_DESIGN_BUTTON)
   target_sources(app PRIVATE
     helpers/ui-button/ui_task.c
+    helpers/ui-button/time_sync.c
   )
   target_include_directories(app PRIVATE
     ${CMAKE_CURRENT_SOURCE_DIR}/helpers/ui-button

zephcore/Kconfig

@@ -620,6 +620,18 @@ config ZEPHCORE_UI_DISPLAY_AUTO_OFF_MS
 	  Time in milliseconds before the display turns off
 	  after the last user interaction. Set to 0 to disable.
 
+config ZEPHCORE_UI_TIME_SOURCE_FRESH_HOURS
+	int "Clock source tag freshness window (hours)"
+	default 12
+	help
+	  The top-bar clock shows a one-character source tag: G (GPS),
+	  A (app), N (network/SNTP). If the most recent sync from one of
+	  those sources is older than this many hours, the tag falls back
+	  to L (local) — the RTC is free-running on its own oscillator.
+	  Set to 0 to keep the last external source tag indefinitely
+	  (no freshness expiry). Drift on a 50 ppm crystal is ~4 s/day,
+	  so this is a trust/freshness signal, not an accuracy limit.
+
 config ZEPHCORE_AUTO_SHUTDOWN_MILLIVOLTS
 	int "Low-battery auto-shutdown threshold (mV, 0 = disabled)"
 	default 3300 if SOC_SERIES_NRF52

zephcore/helpers/CommonCLI.cpp

@@ -5,6 +5,7 @@
 
 #include "CommonCLI.h"
 #include "battery_curve.h"
+#include <helpers/time_sync.h>
 #include <helpers/TxtDataHelpers.h>
 #include <helpers/AdvertDataHelpers.h>
 #include <adapters/board/ZephyrBoard.h>
@@ -331,6 +332,7 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, const char* command, ch
         uint32_t curr = getRTCClock()->getCurrentTime();
         if (sender_timestamp > curr) {
             getRTCClock()->setCurrentTime(sender_timestamp + 1);
+            time_sync_report(TIME_SYNC_CLI);
             uint32_t now = getRTCClock()->getCurrentTime();
             time_t t = (time_t)now;
             struct tm *tm = gmtime(&t);
@@ -350,6 +352,7 @@ void CommonCLI::handleCommand(uint32_t sender_timestamp, const char* command, ch
         uint32_t curr = getRTCClock()->getCurrentTime();
         if (secs > curr) {
             getRTCClock()->setCurrentTime(secs);
+            time_sync_report(TIME_SYNC_CLI);
             time_t t = (time_t)secs;
             struct tm *tm = gmtime(&t);
             snprintf(reply, CLI_REPLY_SIZE, "OK - clock set: %02d:%02d - %d/%d/%d UTC",

zephcore/helpers/time_sync.h

@@ -19,10 +19,14 @@ enum time_sync_source {
 	TIME_SYNC_CLI,
 };
 
-#if IS_ENABLED(CONFIG_ZEPHCORE_UI_DESIGN_JOYSTICK)
+#if IS_ENABLED(CONFIG_ZEPHCORE_UI_DESIGN_JOYSTICK) || \
+    IS_ENABLED(CONFIG_ZEPHCORE_UI_DESIGN_BUTTON)
 
 void time_sync_report(enum time_sync_source src);
-const char *time_sync_display_label(void);
+
+/* Current effective time source (prefers live GPS sync). TIME_SYNC_NONE
+ * if the RTC has never been set. */
+enum time_sync_source time_sync_get_source(void);
 
 #else
 
@@ -31,7 +35,16 @@ static inline void time_sync_report(enum time_sync_source src)
 	ARG_UNUSED(src);
 }
 
-#endif /* CONFIG_ZEPHCORE_UI_DESIGN_JOYSTICK */
+static inline enum time_sync_source time_sync_get_source(void)
+{
+	return TIME_SYNC_NONE;
+}
+
+#endif /* CONFIG_ZEPHCORE_UI_DESIGN_JOYSTICK || _BUTTON */
+
+#if IS_ENABLED(CONFIG_ZEPHCORE_UI_DESIGN_JOYSTICK)
+const char *time_sync_display_label(void);
+#endif
 
 #ifdef __cplusplus
 }

zephcore/helpers/ui-button/time_sync.c

@@ -0,0 +1,42 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * Button UI: track which source last set the RTC, for the top-bar clock tag.
+ *
+ * The tag reflects *freshness*: an external sync (GPS / app / network) is
+ * shown only while it is recent (CONFIG_ZEPHCORE_UI_TIME_SOURCE_FRESH_HOURS).
+ * Once it ages out — or after a reboot, before any sync — the source reads as
+ * local (the RTC is free-running on its own oscillator).
+ */
+
+#include <time_sync.h>
+#include <zephyr/kernel.h>
+
+static enum time_sync_source s_last = TIME_SYNC_NONE;
+static int64_t s_last_uptime;   /* k_uptime_get() at the last report */
+
+void time_sync_report(enum time_sync_source src)
+{
+	s_last = src;
+	s_last_uptime = k_uptime_get();
+}
+
+enum time_sync_source time_sync_get_source(void)
+{
+	/* Local/manual (CLI) and "never synced" are both just local time. */
+	if (s_last == TIME_SYNC_NONE || s_last == TIME_SYNC_CLI) {
+		return TIME_SYNC_CLI;
+	}
+
+#if CONFIG_ZEPHCORE_UI_TIME_SOURCE_FRESH_HOURS > 0
+	int64_t age_ms = k_uptime_get() - s_last_uptime;
+	int64_t window_ms =
+		(int64_t)CONFIG_ZEPHCORE_UI_TIME_SOURCE_FRESH_HOURS * 3600 * 1000;
+
+	if (age_ms > window_ms) {
+		/* External sync has gone stale — fall back to local. */
+		return TIME_SYNC_CLI;
+	}
+#endif
+
+	return s_last;   /* GPS / APP / WIFI, still fresh */
+}

zephcore/helpers/ui-button/ui_pages.c

@@ -18,6 +18,7 @@
 #include "ui_task.h"
 #include "display.h"
 
+#include <time_sync.h>
 #include <ZephyrSensorManager.h>
 
 #include <zephyr/kernel.h>
@@ -123,49 +124,72 @@ static uint8_t calc_battery_pct(uint16_t mv)
 
 /* ========== Helper: Top Bar (Node Name + Battery) ========== */
 
+/* One-char tag for where the displayed clock was last freshly synced from
+ * (see time_sync_get_source() for the freshness window). Always returns a
+ * letter — falls back to 'L' (local) when no recent external sync. */
+static char time_source_tag(enum time_sync_source src)
+{
+	switch (src) {
+	case TIME_SYNC_GPS:  return 'G';  /* GPS fix */
+	case TIME_SYNC_APP:  return 'A';  /* phone/companion app */
+	case TIME_SYNC_WIFI: return 'N';  /* network (SNTP) */
+	default:             return 'L';  /* local: manual/CLI or stale/none */
+	}
+}
+
 static void render_top_bar(void)
 {
-	/* Node name on the left */
-	if (state.node_name[0]) {
-		/* Truncate to fit left side (leave room for battery) */
-		char name[16];
+	/* Right side: "HH:MM<S> XX%" — clock (with 1-char source tag) then
+	 * battery, right-aligned.  Built first so the node name can be clipped
+	 * to the space that remains on the left, preventing overlap. */
+	char right[16] = "";
+	int pos = 0;
 
-		strncpy(name, state.node_name, sizeof(name) - 1);
-		name[sizeof(name) - 1] = '\0';
-		mc_display_text(0, TOP_BAR_Y, name, false);
+	/* 24h clock from RTC epoch (only if time has been synced).
+	 * Before sync, getCurrentTime() returns bare uptime (~seconds),
+	 * so check for a sane epoch (after Jan 1 2025 = 1735689600). */
+	if (state.rtc_epoch > 1735689600) {
+		uint32_t day_sec = state.rtc_epoch % 86400;
+		uint8_t hh = day_sec / 3600;
+		uint8_t mm = (day_sec % 3600) / 60;
+
+		/* Source tag: G=GPS, A=app, N=network, L=local (always set). */
+		char src = time_source_tag(time_sync_get_source());
+
+		pos = snprintf(right, sizeof(right), "%02u:%02u%c ", hh, mm, src);
 	}
 
-	/* Right side: "HH:MM XX%" — clock then battery, right-aligned */
-	{
-		char right[16] = "";
-		int pos = 0;
+	/* Battery percentage */
+	if (state.battery_mv > 0) {
+		uint8_t pct = state.battery_pct;
 
-		/* 24h clock from RTC epoch (only if time has been synced).
-		 * Before sync, getCurrentTime() returns bare uptime (~seconds),
-		 * so check for a sane epoch (after Jan 1 2025 = 1735689600). */
-		if (state.rtc_epoch > 1735689600) {
-			uint32_t day_sec = state.rtc_epoch % 86400;
-			uint8_t hh = day_sec / 3600;
-			uint8_t mm = (day_sec % 3600) / 60;
-
-			pos = snprintf(right, sizeof(right), "%02u:%02u ", hh, mm);
+		if (pct == 0) {
+			pct = calc_battery_pct(state.battery_mv);
 		}
+		snprintf(right + pos, sizeof(right) - pos, "%u%%", pct);
+	}
 
-		/* Battery percentage */
-		if (state.battery_mv > 0) {
-			uint8_t pct = state.battery_pct;
+	int right_x = DISP_W;
+	if (right[0]) {
+		right_x = DISP_W - ((int)strlen(right) * FONT_W);
+		mc_display_text(right_x, TOP_BAR_Y, right, false);
+	}
 
-			if (pct == 0) {
-				pct = calc_battery_pct(state.battery_mv);
-			}
-			snprintf(right + pos, sizeof(right) - pos, "%u%%", pct);
+	/* Node name on the left, clipped to the gap before the right block
+	 * (one char-width of padding so it never touches the clock). */
+	if (state.node_name[0]) {
+		char name[16];
+		int max_chars = (right_x - FONT_W) / FONT_W;
+
+		if (max_chars > (int)sizeof(name) - 1) {
+			max_chars = sizeof(name) - 1;
 		}
-
-		if (right[0]) {
-			int x = DISP_W - ((int)strlen(right) * FONT_W);
-
-			mc_display_text(x, TOP_BAR_Y, right, false);
+		if (max_chars < 0) {
+			max_chars = 0;
 		}
+		strncpy(name, state.node_name, max_chars);
+		name[max_chars] = '\0';
+		mc_display_text(0, TOP_BAR_Y, name, false);
 	}
 }
 

zephcore/helpers/ui-joystick/time_sync.c

@@ -4,9 +4,11 @@
 
 #include <time_sync.h>
 #include <adapters/gps/ZephyrGPSManager.h>
+#include <zephyr/kernel.h>
 #include <stdio.h>
 
 static enum time_sync_source s_last = TIME_SYNC_NONE;
+static int64_t s_last_uptime;   /* k_uptime_get() at the last report */
 
 static const char *source_short_name(enum time_sync_source src)
 {
@@ -22,6 +24,30 @@ static const char *source_short_name(enum time_sync_source src)
 void time_sync_report(enum time_sync_source src)
 {
 	s_last = src;
+	s_last_uptime = k_uptime_get();
+}
+
+/* Freshness-windowed source for the top-bar clock tag. Local/manual (CLI)
+ * and "never synced" both read as local; an external sync ages out after
+ * CONFIG_ZEPHCORE_UI_TIME_SOURCE_FRESH_HOURS. (Distinct from the System >
+ * Info > Time label below, which is not time-windowed.) */
+enum time_sync_source time_sync_get_source(void)
+{
+	if (s_last == TIME_SYNC_NONE || s_last == TIME_SYNC_CLI) {
+		return TIME_SYNC_CLI;
+	}
+
+#if CONFIG_ZEPHCORE_UI_TIME_SOURCE_FRESH_HOURS > 0
+	int64_t age_ms = k_uptime_get() - s_last_uptime;
+	int64_t window_ms =
+		(int64_t)CONFIG_ZEPHCORE_UI_TIME_SOURCE_FRESH_HOURS * 3600 * 1000;
+
+	if (age_ms > window_ms) {
+		return TIME_SYNC_CLI;
+	}
+#endif
+
+	return s_last;
 }
 
 const char *time_sync_display_label(void)