diff --git a/ch32v003/gcc.mk b/ch32v003/gcc.mk
index 713da29..a13e1d2 100644
--- a/ch32v003/gcc.mk
+++ b/ch32v003/gcc.mk
@@ -7,11 +7,11 @@ SIZE = $(PREFIX)size
 DUMP = $(PREFIX)objdump
 COPY = $(PREFIX)objcopy
 OBJS  += startup.o system.o
-CFLAGS+= -Os -flto
+CFLAGS+= -Os
 CCPU   = -march=rv32ec -mabi=ilp32e
 MCPU   = $(CCPU)
 CFLAGS+= $(MCPU)
 LFLAGS+= -Wl,--Map=$(@:%.elf=%.map),--gc-sections
 #LFLAGS+= -Wl,--print-sysroot -- chyba ld ?
-LFLAGS+= -flto -O3 $(MCPU) -nostartfiles -nostdlib
+LFLAGS+= -O3 $(MCPU) -nostartfiles -nostdlib
 LDLIBS+= -lgcc -L./$(TARGET) -T generated_ch32v003.ld
diff --git a/midi/main.cpp b/midi/main.cpp
index 0f68daf..062738d 100644
--- a/midi/main.cpp
+++ b/midi/main.cpp
@@ -7,10 +7,15 @@ static PcmDma     pcm;
 int main (void) {
   pcm.attach (player);
   for (;;) {
+    player.pass();
     /* BUG:
      * Do smyčky nejde přidat jakýkoli další kód.
      * Proč, neumím vysvětlit, ale lze to izolovat.
      * Je zajímavé, že ADC postavené podobně to nedělá.
+     * 
+     * FIX: 1. Vynechat LTO optimalizaci. Optimalizuje asi moc, ale zase tak moc neušetří.
+     *      2. Činnost nechat v metodě pass() hlavní třídy.
+     * Zřejmě je tam nějaký problém s voláním konstruktorů.
      * */
   }
   return 0;
diff --git a/midi/mid/demo10.mid b/midi/mid/demo10.mid
new file mode 100644
index 0000000..d7cb2e2
Binary files /dev/null and b/midi/mid/demo10.mid differ
diff --git a/midi/mid/joy.mid b/midi/mid/joy.mid
deleted file mode 100644
index 10d72aa..0000000
Binary files a/midi/mid/joy.mid and /dev/null differ
diff --git a/midi/midiplayer.cpp b/midi/midiplayer.cpp
index 497cfa6..6773fcc 100644
--- a/midi/midiplayer.cpp
+++ b/midi/midiplayer.cpp
@@ -48,12 +48,18 @@ static unsigned pwm_sd (const int input) {
 
 /******************************************************************/
 /// Konstruktor
-MidiPlayer::MidiPlayer() noexcept : OneWay()  {
+MidiPlayer::MidiPlayer() noexcept : OneWay(), led (LED_CFG), passcnt (0u) {
   index = 0;
   pause = 0;
   melody  = scores[index++];
   running = true;
 }
+void MidiPlayer::pass() {
+  const bool b = passcnt & 0x10000;
+  led << b;
+  passcnt += 1u;
+}
+
 unsigned MidiPlayer::Send (uint16_t * const ptr, const unsigned len) {
 //if (!but.get()) running = true;  // případně spouštět tlačítkem, není implementováno
   
@@ -69,11 +75,12 @@ unsigned MidiPlayer::Send (uint16_t * const ptr, const unsigned len) {
   return len;
 }
 void MidiPlayer::stop (void) {
-//running = false;                // cyklicky, furt
+//running = false;                // na konci každé melodie stop
   melody = scores[index++];
   if (!melody) {
-    index  = 0;
-    melody = scores[index++];
+    index   = 0;
+    melody  = scores[index++];
+    running = false; // test bez tlačítka
   }
 }
 void MidiPlayer::ToneChange (void) {
diff --git a/midi/midiplayer.h b/midi/midiplayer.h
index 60a1efc..7774756 100644
--- a/midi/midiplayer.h
+++ b/midi/midiplayer.h
@@ -10,8 +10,8 @@ class MidiPlayer : public OneWay {
     /// Konstruktor
     explicit MidiPlayer () noexcept;
     unsigned Send (uint16_t * const ptr, const unsigned len) override;
-    //bool send (uint16_t * ptr, const int len) override;
-    void stop   ();
+    void     stop ();
+    void     pass ();
   protected:
   // Chráněné metody
     /// Obsluha tónu
@@ -19,7 +19,8 @@ class MidiPlayer : public OneWay {
     /// Obsluha vzorku
     short nextSample (void);
   private:
-    //GpioClass             but;
+    GpioClass             led;
+    unsigned              passcnt;
     volatile bool         running;
     unsigned char const * melody;
     unsigned              index;
diff --git a/midi/pwmconfig.h b/midi/pwmconfig.h
index 2ef2bb7..0fac579 100644
--- a/midi/pwmconfig.h
+++ b/midi/pwmconfig.h
@@ -4,4 +4,12 @@
 static constexpr unsigned HALF_LEN = 0x80u;
 static constexpr unsigned MAXPWM   = 2000u;
 
+#ifdef __riscv
+#define LED_CFG GPIOD,4
+#elif __arm__
+#define LED_CFG GpioPortA,0
+#else
+#error "bad target"
+#endif
+
 #endif // CONFIG_H