diff --git a/cpu.cpp b/cpu.cpp
index 9f56170..3dfd105 100644
--- a/cpu.cpp
+++ b/cpu.cpp
@@ -48,11 +48,6 @@ void cpu::reset()
 	runMode = false;
 }
 
-void cpu::setDisassemble(const bool state)
-{
-	disas = state;
-}
-
 uint16_t cpu::getRegister(const int nr, const bool prev_mode) const
 {
 	if (nr < 6)
@@ -1494,8 +1489,8 @@ cpu::operand_parameters cpu::addressing_to_string(const uint8_t mode_register, c
 
 std::map<std::string, std::vector<std::string> > cpu::disassemble(const uint16_t addr) const
 {
-	bool old_debug_output     = debug_output;
-	debug_output = false;
+	bool old_trace_output     = trace_output;
+	trace_output = false;
 
 	uint16_t    pc            = getPC();
 	uint16_t    instruction   = b->peekWord(pc);
@@ -1907,7 +1902,7 @@ std::map<std::string, std::vector<std::string> > cpu::disassemble(const uint16_t
 		work_values_str.push_back(format("%06o", v));
 	out.insert({ "work-values", work_values_str });
 
-	debug_output = old_debug_output;
+	trace_output = old_trace_output;
 
 	return out;
 }
@@ -1959,9 +1954,6 @@ void cpu::step()
 		busError();
 
 	try {
-		if (disas)
-			disassemble();
-
 		uint16_t instr = b->readWord(temp_pc);
 
 		addRegister(7, false, 2);
diff --git a/cpu.h b/cpu.h
index e309ecc..d98cfe0 100644
--- a/cpu.h
+++ b/cpu.h
@@ -13,7 +13,6 @@
 class cpu
 {
 private:
-	bool     disas { false };
 	uint16_t regs0_5[2][6]; // R0...5, selected by bit 11 in PSW, 
 	uint16_t sp[3 + 1]; // stackpointers, MF../MT.. select via 12/13 from PSW, others via 14/15
 	uint16_t pc    { 0 };
@@ -63,7 +62,6 @@ public:
 	explicit cpu(bus *const b, uint32_t *const event);
 	~cpu();
 
-	void setDisassemble(const bool state);
 	void disassemble(void) const;
 	std::map<std::string, std::vector<std::string> > disassemble(const uint16_t addr) const;
 
diff --git a/gen.h b/gen.h
index e633e04..a5b3e2e 100644
--- a/gen.h
+++ b/gen.h
@@ -2,13 +2,13 @@
 // Released under Apache License v2.0
 #pragma once
 
-extern bool debug_output;
+extern bool trace_output;
 
 #if defined(ESP32)
 #define D(...) do { } while(0);
 #else
 #ifndef NDEBUG
-#define D(x) do { if (debug_output) { x } } while(0);
+#define D(x) do { if (trace_output) { x } } while(0);
 #else
 #define D(...) do { } while(0);
 #endif
diff --git a/main.cpp b/main.cpp
index 5527da1..cf5944d 100644
--- a/main.cpp
+++ b/main.cpp
@@ -22,7 +22,7 @@ bool              withUI       { false };
 uint32_t          event        { 0 };
 std::atomic_bool  terminate    { false };
 std::atomic_bool *running      { nullptr };
-bool              debug_output { false };
+bool              trace_output { false };
 
 void loadbin(bus *const b, uint16_t base, const char *const file)
 {
@@ -148,7 +148,8 @@ void help()
 	printf("-p 123   set CPU start pointer to decimal(!) value\n");
 	printf("-L f.bin load file into memory at address given by -p (and run it)\n");
 	printf("-n       ncurses UI\n");
-	printf("-d       enable disassemble\n");
+	printf("-d       enable debugger\n");
+	printf("-t       enable tracing (disassemble to stderr, requires -d as well)\n");
 }
 
 int main(int argc, char *argv[])
@@ -163,7 +164,9 @@ int main(int argc, char *argv[])
 
 	std::vector<std::string> rk05_files;
 	bool testCases = false;
-	int opt = -1;
+	bool debugger  = false;
+	bool tracing   = false;
+	int  opt       = -1;
 	while((opt = getopt(argc, argv, "hm:T:R:p:ndL:")) != -1)
 	{
 		switch(opt) {
@@ -172,8 +175,12 @@ int main(int argc, char *argv[])
 				return 1;
 
 			case 'd':
-				c->setDisassemble(true);
-				debug_output = true;
+				debugger = true;
+				break;
+
+			case 't':
+				tracing      = true;
+				trace_output = true;
 				break;
 
 			case 'n':
@@ -261,8 +268,18 @@ int main(int argc, char *argv[])
 
 	c->emulation_start();  // for statistics
 
-	while(!event && !terminate)
-		c->step();
+	if (debugger) {
+		while(!event && !terminate) {
+			if (tracing)
+				c->disassemble();
+
+			c->step();
+		}
+	}
+	else {
+		while(!event && !terminate)
+			c->step();
+	}
 
 	*running = false;