From e41bbeeaa6562ed12559ade5bc415e146e594954 Mon Sep 17 00:00:00 2001
From: garbhitsh <garbhitsharmaemail@gmail.com>
Date: Mon, 10 Aug 2026 18:34:41 +0530
Subject: [PATCH] Fix hw---gdk simulator crash: add readP0Adc simulator
 fallback

The Game Designer's Kit battery monitor (batteryled.ts) calls the native
gdk.readP0Adc() SAADC shim on a background loop. That shim has no
simulator implementation, so running any project with hw---gdk selected
throws 'Cannot read properties of undefined (reading readP0Adc)' in the
simulator a couple of seconds after start.

Provide a TypeScript fallback body for the shim (as libs/storage does for
storage::init): on micro:bit V2 the C++ SAADC read in analog.cpp is still
used; in the simulator the fallback returns a full-battery reading (1023)
so the battery monitor and games run without error. Replace the
declaration-only shims.d.ts with analog.ts and update pxt.json.

No device behavior change.
---
 libs/hw---gdk/analog.ts  | 15 +++++++++++++++
 libs/hw---gdk/pxt.json   |  2 +-
 libs/hw---gdk/shims.d.ts | 22 ----------------------
 3 files changed, 16 insertions(+), 23 deletions(-)
 create mode 100644 libs/hw---gdk/analog.ts
 delete mode 100644 libs/hw---gdk/shims.d.ts

diff --git a/libs/hw---gdk/analog.ts b/libs/hw---gdk/analog.ts
new file mode 100644
index 0000000000..9a5ea0408e
--- /dev/null
+++ b/libs/hw---gdk/analog.ts
@@ -0,0 +1,15 @@
+namespace gdk {
+    /**
+     * Blocking single-shot ADC read of P0 (P0.02 / AIN0). Returns 0..1023 (same
+     * scale as pins.analogReadPin), or -1 on hardware timeout.
+     *
+     * On micro:bit V2 the native SAADC implementation in analog.cpp is used.
+     * The body below is the simulator fallback: there is no SAADC in the
+     * simulator, so it reports a full battery (1023) to keep the battery
+     * monitor and any game running without a runtime error.
+     */
+    //% shim=gdk::readP0Adc
+    export function readP0Adc(): number {
+        return 1023;
+    }
+}
diff --git a/libs/hw---gdk/pxt.json b/libs/hw---gdk/pxt.json
index 4e69a8afbd..d49b48e17c 100644
--- a/libs/hw---gdk/pxt.json
+++ b/libs/hw---gdk/pxt.json
@@ -4,9 +4,9 @@
     "files": [
         "config.ts",
         "init.ts",
+        "analog.ts",
         "batteryled.ts",
         "device.d.ts",
-        "shims.d.ts",
         "analog.cpp"
     ],
     "card": {
diff --git a/libs/hw---gdk/shims.d.ts b/libs/hw---gdk/shims.d.ts
deleted file mode 100644
index 99c7b5341c..0000000000
--- a/libs/hw---gdk/shims.d.ts
+++ /dev/null
@@ -1,22 +0,0 @@
-// Auto-generated. Do not edit.
-declare namespace gdk {
-
-    /**
-     * Blocking single-shot ADC read of P0 (P0.02 / AIN0). Returns 0..1023 (same
-     * scale as pins.analogReadPin), or -1 on hardware timeout.
-     *
-     * Absolute internal 0.6V reference + gain 1/6 => full scale 3.6V (VDD-independent,
-     * so the reading stays correct as the battery/VDD drains). 40us acquisition suits
-     * the on-board ~82k divider.
-     *
-     * Owns the SAADC exclusively for the ~50us the conversion takes, then fully
-     * disables it. It does NOT touch PPI/timers/IRQs, so it cannot disturb the
-     * display or audio. The complete manual sequence is:
-     *   ENABLE -> START -> (STARTED) -> SAMPLE -> (END) -> STOP -> (STOPPED) -> DISABLE
-     * The SAMPLE task is the critical step the previous version was missing.
-     */
-    //% shim=gdk::readP0Adc
-    function readP0Adc(): int32;
-}
-
-// Auto-generated. Do not edit. Really.